Morphology of Third Mandibular Molars – An In Vivo Cone Beam Computed Tomography Study in Lower Silesia

Morphology of Third Mandibular Molars – An In Vivo Cone Beam Computed Tomography Study in Lower Silesia | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Morphology of Third Mandibular Molars – An In Vivo Cone Beam Computed Tomography Study in Lower Silesia Anna Olczyk, Barbara Malicka, Paweł Stenzel, Urszula Sękowska, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8282672/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 13 You are reading this latest preprint version Abstract Background Understanding the root and canal morphology of mandibular third molars (MTMs) is crucial for anatomical characterization of human dentition and effective endodontic treatment. This study investigates the number of roots, canal configurations, and the prevalence of C-shaped canals in MTMs using Cone Beam Computed Tomography (CBCT). Objectives To analyse root count, sex-related differences, canal configurations, and the prevalence of C-shaped canals in MTMs. Methods This cross-sectional study analysed CBCT scans of 261 MTMs from patients aged 18 and over according to Vertucci’s classification. Data were collected at the X-Ray Diagnostic Laboratory of (city name anonymized due to double blind policy) Medical University from January to April 2022. Interobserver agreement was excellent (κ = 0.917). Statistical analyses included chi-squared tests with Bonferroni correction (p < 0.05). Effect size was assessed using Cohen’s “w” (0.0172) with test power of 0.64 at an alpha level of 0.05. Results Most MTMs had two roots (79.69%), followed by three roots (11.81%) and a single root (8.43%). Two-rooted teeth were more frequent in males (87.27%) than in females (74.17%, p = 0.027). Type I was the predominant root canal configuration in all categories. C-shaped canals were present in 5.36% of teeth, predominantly in single-rooted teeth (71.43%) and females (92.86%). Conclusions This study highlights variations in anatomical diversity of MTMs, emphasizing clinical importance of CBCT for accurate diagnosis and treatment planning, expanding anatomical knowledge. Findings underscore the prevalence of C-shaped canals and sex-related differences in root structure. Mandibular third molars CBCT root canal morphology C-shaped canals Vertucci classification dental anatomy root canal configuration sex differences Figures Figure 1 Figure 2 Figure 3 1. Introduction Mandibular third molars (MTMs), commonly referred to as wisdom teeth, exhibit significant anatomical variability, posing challenges for dental practitioners in endodontic and surgical procedures. Accurate knowledge of root canal morphology is essential for effective treatment planning and achieving successful clinical outcomes. Although numerous studies have investigated the anatomy of mandibular first (Al-Habib et al. , 2024) and second molars (Yang et al. , 2022), research focusing specifically on mandibular third molars remains limited (Al-Qudah et al. , 2023). Notably, to date, only one study has examined MTMs in the Polish population (Tomaszewska et al. , 2018). Understanding the anatomical complexity of MTMs is critical for successful endodontic treatment. Beyond their functional role, MTMs can also serve important purposes when opposing teeth are absent, such as acting as fixed prosthetic abutments, providing support for partial dentures, or being used for autotransplantation (De Bruyn et al. , 2020). Current research on root canal configurations on MTMs reveals several gaps. Many studies lack population diversity, which limits the generalizability of findings to other groups.(Ahmad et al. , 2016; Somasundaram, 2017; Tomaszewska et al. , 2018; Singh et al. , 2020; Priyank et al. , 2023). Additionally, the absence of standardized terminology and classification systems makes direct comparisons across studies difficult. Inconsistencies in data presentation, limited statistical analyses, small sample sizes, and insufficient stratification further reduce the reliability and applicability of existing findings. In this study, the root canal morphology of the MTM was investigated in a population from Lower Silesia using CBCT imaging. Lower Silesia is designated as the PL5 region under the Nomenclature of Territorial Units for Statistics (NUTS), with its capital in Wrocław (PL514). The research question was what is the most common configuration of the root canal system in the mandibular third molars (MTM). The use of cone-beam computed tomography (CBCT) in this study is well-justified based mainly on its balance of accuracy, accessibility, and clinical applicability. While micro-computed tomography (micro-CT) offers higher resolution, it could not be used in vivo due to high radiation exposure (Ahmed, 2022). In contrast, CBCT provides three-dimensional imaging with sufficient detail for clinical research and is widely available, making it both practical and ethical for human studies (Neelakantan, Subbarao and Subbarao, 2010; Naseri et al. , 2019) Although clearing and staining have historically been considered the gold standard, CBCT has shown comparable accuracy (Drăgan, Fărcăşanu, Câmpian, et al. 2016; Shihab & Mahdee 2021). CBCT also allows for larger sample sizes than staining methods, increasing statistical power and generalizability (Sun et al. , 2016). Despite some resolution limitations, CBCT offers a reliable, non-invasive method for root canal analysis and is currently one of the best options for clinical use. This study investigates the root canal morphology of MTMs in a population from Lower Silesia using CBCT imaging. Specifically, it addresses the following questions: How many roots are most commonly present in mandibular third molars (MTMs)? Are there significant differences in the number of roots in MTMs between males and females? What are the most common root canal configurations in mandibular third molars? What is the prevalence of C-shaped root canals in MTMs? To address these objectives, CBCT scans of MTMs were analysed, classifying root and canal systems based on Vertucci’s system and assessing sex-based variations. Furthermore, this study aims to comprehensively compare its findings to existing literature to contribute to a deeper understanding of MTM morphology. 2. Material and Methods 2.1 Data Collection The study was designed and reported in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines(von Elm et al. , 2008). The CBCT scans were obtained from the Academic Dental Polyclinic of (city name anonymized due to double blind policy) Medical University in Poland, specifically from the X-Ray Diagnostic Laboratory. These scans were conducted for diagnostic or other dental purposes between January and April 2022 using a Rayscan α-Plus 130 (Rayscan 700) CBCT scanner (Ray Europe GmbH, Seoul, South Korea). The scanner's specifications included a field of view ranging from 3x4 cm to 13x10 cm, with settings of 60–90 kV, 4–17 mA, a scan duration of 14 seconds, and voxel sizes of 70 µm, 160 µm, 200 µm, or 280 µm. The slice thickness varied from 0.07 mm to 3 mm. To standardize the study, full-mouth CBCT scans with a voxel size of 160 µm, slice thickness of 0.16 mm, field of view of 13x10 cm, and settings of 90 kV and 4 mA were used. Data were reviewed using Rayscan SMART Dent software (Ray Co., Ltd, Seoul, South Korea) and OnDemand3DApp software (Cyber Med, Seoul, South Korea). Research access to the data was granted on June 7, 2022. Study approval was obtained from the Bioethics Committee of (city name anonymized due to double blind policy) Medical University (approval no. KB 206/2022), in accordance with the Declaration of Helsinki. Informed consent was obtained, and data were anonymized to ensure that participants could not be identified. Following the analysis of 316 CBCT scans from a potential total of 632 teeth, 261 mandibular third molars met the inclusion criteria. The images were evaluated by two endodontists with 5 and 30 years of professional experience, respectively. Disagreements were resolved through consensus. A Beacon Display C25W screen (Shenzhen Beacon Display Technology Co., Ltd.) was used for analysis, featuring a resolution of 1920 x 1080 pixels. Various image adjustments, including zoom, magnification, brightness, and contrast, were applied as needed. Assessments were performed in a dimly lit room, with no more than 15 scans evaluated per session to minimize fatigue. Inclusion criteria were: participants aged 18 or older (continuous variable, with no further categorization); teeth without caries, fillings, prosthetic crowns, or post-core inlays; teeth without previous endodontic treatment; teeth with closed apices, free from resorptions or calcifications; and artifact-free CBCT images. Tooth rotation (mesiolingual or distolingual) did not disqualify the tooth from the study. The number of roots, root canals, and root canal configurations were assessed according to Vertucci's classification (1974) (Vertucci, Seelig and Gillis, 1974), which categorizes root canal morphology into eight distinct types (I-VIII) based on the number and configuration of canals from the pulp chamber to the apex, representing specific patterns of how canals may branch, merge, or remain separate throughout the root. Root and root canal number were treated as categorical variables. It must be noted that some canal anatomy variations are impossible to describe using this method, so some authors proposed the expansion of this classification to include several other canal configurations (Al-Qudah et al. , 2023; Gulabivala and Ng, 2023). Recently new system has been proposed, and it remains to be seen whether it will see wider implementation (Ahmed et al. , 2017). Vertucci's classification delineates root canal configurations as follows: Type I – single canal from the pulp chamber to the apex of the root Type II – two canals exit the pulp chamber and join into one canal to the apex of the root Type III – single canal leaves the pulp to divide into two and then join again and finish at the apex of the root Type IV – two canals leave the pulp chamber and two canals continue to the apex Type V – single canal leaves the pulp chamber and divides into two canals that continue to the apex Type VI – two canals leave the pulp chamber, then merge into one and divide into two again and finish as to canals to the apex Type VII – single canal leaves the pulp chamber, then divides into two, then merges into one to finally divide into two canals and finish as two canals at the apex Type VIII – three canals leave the pulp chamber, and three canals exit to the apex. Before evaluating the CBCT scans, both endodontists underwent training and calibration using sample CBCTs representing the eight types of Vertucci's classification. Cohen's kappa statistic was calculated to evaluate interobserver agreement, yielding a value of 91.7%, indicating excellent agreement ((McHugh, 2012). 2.2 Statistical Analysis Data analysis was conducted by the Statistical Analysis Center of (city name anonymized due to double blind policy) Medical University using Statistica 13 (2017) software (TIBCO Software Inc., USA). The analysis included the number of roots (Table 1 ), the number of roots by sex (Table 2 , Table 3 ), and Vertucci’s classification (Tables 4 and 5 ). Table 2 presents chi-squared and p-values comparing the frequency of each tooth type by sex. The chi-squared test yielded a significance level below 0.05 (Table 2 ). The Bonferroni correction was applied to control for Type I error, adjusting for incidental findings of significant differences. The threshold for statistical significance was set at 0.05. Confidence intervals for the observed rates are provided in Tables 1 and 6. All available scans (n = 316) were analysed, and the power of the analysis for mandibular third molars meeting the inclusion criteria (n = 261) was calculated afterwards using the “power.chisq.test” function from the “DescTools” R package. The chi-squared test on 2x4 tables indicated that a sample size of 261 allows for the detection of Cohen’s effect size “w” of 0.172 with a power of 0.64 and an alpha level of 0.05 (two-tailed test). A power of 0.64 means there is a 64% probability of detecting an effect size of 0.172 if it truly exists. This suggests a reasonable chance of detecting a small to medium effect, though there is still a 36% chance of failing to detect an effect if it is present. According to Cohen’s classification, an effect size of w = 0.172 is considered between “small” (0.1) and “medium” (0.3). Control for confounding was addressed by inclusion criteria, no additional statistical adjustment for confounding was applied. Only artifact-free CBCT images were included; as a result, no missing data were present in the analyses. All available scans meeting the inclusion criteria were analyzed; no complex sampling strategy was applied, and hence no analytical methods to account for sampling design were required. Sensitivity analyses were not applicable in this study. The study adhered to the guidelines outlined in the Anatomical Quality Assurance (AQUA) checklist (Tomaszewski et al. , 2017) attached in supplement 1. 3. Results 3.1 Characteristics of the Study Population Out of an initial set of 632 potential teeth, 316 CBCT scans were analysed. From these, 261 mandibular third molars were selected for evaluation. These teeth came from 151 females (57.9%) and 110 males (42.1%). The absence of the mandibular third molar, the exclusion of the area of examination, and the patient's age were the main reasons for excluding teeth from the study group. Figure 1 shows the inclusion and exclusion criteria for the study. 3.2 Root Count (overall) Out of the 261 teeth scans analysed, two-rooted teeth were the most prevalent, accounting for 79.69% (n = 208). Three-rooted teeth were less common, at 11.81% (n = 31), and single-rooted teeth were the least common, making up 8.43% (n = 22) (see Table 1 , Chart 1 ). Table 1 Distribution (%) of roots in mandibular third molars with 95% confidence intervals (CI) Number of roots Total n % Proportion 95% CI 1 22 8.43 0.08 (0.05; 0.12) 2 208 79.69 0.8 (0.74; 0.84) 3 31 11.88 0.12 (0.08; 0.16) Total number 261 100.00 - - 3.3 Root Count by Sex The frequency of occurrence of various mandibular third molar types, categorized by the number of roots, was also evaluated based on patient sex (Table 2 , Table 3 ). Our research revealed that single-rooted mandibular third molars were more prevalent in females compared to males, with 18 teeth (11.92%) in females versus 4 teeth (3.64%) in males, and it was not statistically significant, p = 0.051. Two-rooted forms of mandibular third molars were significantly more common in females than in males, and it was statistically significant (112 teeth, 74.17% vs 96 teeth, 87.27%, p = 0.027) (Table 2 , Table 3 ). Three-rooted teeth occurred more frequently in females (21 teeth, 13.91%) than in males (10 teeth, 9.09%), but the difference was also statistically insignificant (p = 0.705). Table 2 Distribution (%) of roots in mandibular third molars based on sex Number of roots Female Male Chi-square statistic P-value n % n % 1 18 11.92 4 3.64 7.8 0.02 2 112 74.17 96 87.27 3 21 13.91 10 9.09 Total number 151 100 110 100 Statistical significance threshold set at p < 0.05 Table 3 A post hoc test of the differences in the frequency of roots between the sexes (females vs. males) in maxillary third molars with Bonferroni correction Comparison Chi-square statistic P-value 1-root vs. others 5.96 0.051 2-root vs. others 6.57 0.027 3-root vs. others 1.51 0.705 Statistical significance threshold set at p < 0.05 3.4 Root Canal Configurations by Root Count Figure 2 illustrates the distribution of Vertucci canal configurations across the diverse root morphologies observed in this study. This visualization highlights several key trends. Notably, Type I canal configurations are dominant across all root categories, suggesting a fundamental pattern in root canal anatomy. Overall, the most frequently occurring Vertucci types, in descending order, are: I > IV > V > III > II > VIII. The chart also reveals a higher frequency of two canals (corresponding to Type IV configurations) in the mesial roots compared to distal ones. For a more detailed, quantitative analysis, Table 4 presents the frequency and percentage of each Vertucci configuration within the categorized root morphology groups. Furthermore, Table 5 complements this data by providing 95% confidence intervals for the proportions of each Vertucci type within these root morphologies, offering a measure of statistical precision. 3.4.1 Single-rooted Teeth Single-rooted teeth predominantly exhibited Type I root canals according to Vertucci’s classification, with 9 teeth (40.91%) identified as such. Type IV canals were less common, observed in 7 teeth (31.82%). Types III, VI, and VII were absent from the study group, while Type VIII (3 teeth, 13.64%) was found infrequently. Similarly, Types II (2 teeth, 9.09%) and V (1 tooth, 4.55%) were observed sporadically. 3.4.2 Two-rooted Teeth In two-rooted mandibular third molars, Vertucci’s Type I root canal configuration was the most frequently observed in both mesial (133 teeth, 64.42%) and distal (197 teeth, 94.71%) roots. Type IV was also relatively common in the mesial roots, occurring in 62 teeth (29.81%). Types II (8 teeth, 3.85%), III (2 teeth, 0.96%), and V (3 teeth, 1.44%) were also identified. In distal roots, Types II (4 teeth, 1.92%), IV (5 teeth, 2.40%), VI (1 tooth, 0.48%), and VIII (1 tooth, 0.48%) appeared sporadically. Among all the teeth examined, there were only 2 cases of fused roots, and those were among 2 rooted teeth. Two cases of fused roots were observed in two-rooted mandibular third molars, both in female patients, exhibiting Type I canal configurations in distal roots and Type I or Type V configurations in mesial roots. 3.4.3 Three-rooted Teeth Three-rooted teeth exhibited two root configurations. In the first, roots were mesiobuccal (MB), mesiolingual (ML), and distal (D), while in the second, roots were mesial (M), distobuccal (DB), and distolingual (DL). In both configurations, the most common Vertucci classification type was Type I. Types IV and V were less common, with Type IV found in mesial and distal roots, and Type V found in the distolingual root. No teeth with root fusion were identified among three-rooted. Table 4 Vertucci's canal classification in the studied population Vertucci’s canal types Number of roots Root I II III IV V VI VIII n (%) n (%) n (%) n (%) n (%) n (%) n (%) 1 - 9 (40.91) 2 (9.09) 0 7 (31.82) 1 (4.55) 0 3 (13.64) female/male 6/3 2/0 0/0 6/1 1/0 0 3/0 2 M 133 (64.42) 8 (3.85) 2 (0.96) 62 (29.81) 3 (1.44) 0 0 female/male 80/53 4/4 1/1 25/37 2/1 0/0 0/0 D 197 (94.71) 4 (1.92) 0 5 (2.40) 0 1 (0.48) 1 (0.48) female/male 106/91 3/1 0/0 2/3 0/0 1/0 0/1 3 (MB, ML, D) MB 23 (100) 0 0 0 0 0 0 female/male 14/9 0/0 0/0 0/0 0/0 0/0 0/0 ML 23 (100) 0 0 0 0 0 0 female/male 14/9 0/0 0/0 0/0 0/0 0/0 0/0 D 22 (95.65) 0 0 1 (4.35) 0 0 0 female/male 13/9 0/0 0/0 1/0 0/0 0/0 0/0 3 (M, DB, DL) M 6 (75.00) 0 0 2 (25.00) 0 0 0 female/male 5/1 0/0 0/0 2/0 0/0 0/0 0/0 DB 0 0 0 0 0 female/male 7/1 0/0 0/0 0/0 0/0 0/0 DL 7 (87.5) 0 0 0 1 (12.5) 0 0 female/male 6/1 0/0 0/0 0/0 1/0 0/0 0/0 Table 5 Percentages (in relation to the total number of canal types) along with their 95% confidence intervals (CI) Number of roots Root Total number Vertucci’s canal types Type I Type II Type III Type IV Type V Type VIII Proportion 95% CI Proportion 95% CI Proportion 95% CI Proportion 95% CI Proportion 95% CI Proportion 95% CI 22 0.41 0.207; 0.637 0.09 0.011; 0.292 0.00 - 0.32 0.139; 0.549 0.05 0.001; 0.228 0.14 0.029; 0.349 2 M 208 0.64 0.570; 0.705 0.04 0.017; 0.074 0.01 0.001; 0.034 0.30 0.237; 0.365 0.01 0.001; 0.034 - - D 208 0.95 0.913; 0.978 0.02 0.005; 0.049 - - 0.02 0.005; 0.049 - - - - 3 MB 23 1 - - - - - - - - - - - ML 23 1 - - - - - - - - - - - D 23 0.96 0.781; 0.999 - - - - 0.04 0.001; 0.220 - - - - 3 M 8 0.75 0.349; 0.9681 - - - - 0.25 0.032; 0.651 - - - - DB 8 1 - - - - - - - - - - - DL 8 0.88 0.474; 0.997 - - - - - - 0.13 0.003; 0.527 - - 3.5 C-shaped canals C-shaped canals were observed in 5.36% of cases (14 teeth), predominantly in females (13 teeth, 92.86%) compared to males (1 tooth, 7.14%). These canals were found in both single-rooted (10 teeth, 71.43%) and double-rooted (4 teeth, 28.57%) teeth. The only C-shaped canal identified in a male patient was in a single-rooted tooth. Figure 3 presents a pie chart illustrating the distribution of C-shaped canals by sex, highlighting their higher prevalence in females, while other canal morphologies constitute the remaining portion of the sample. Only unadjusted estimates were presented. No confounder-adjusted analyses were performed beyond restriction by inclusion criteria. Precision of estimates was expressed with 95% confidence intervals. Age was recorded as a continuous variable with an inclusion threshold of 18 years; no further categorization was applied. Relative and absolute risk estimates were not applicable in this morphological study. Subgroup analyses were performed by sex for the number of roots and root canal configurations. Post hoc comparisons with Bonferroni correction were conducted to assess differences between male and female participants. No interaction analyses or sensitivity analyses were performed 4. Discussion Mandibular third molars (MTMs) often present with considerable anatomical variability, making them a frequent source of clinical uncertainty in endodontics. Thorough understanding of their morphology is essential not only for successful treatment, but also for avoiding complications during diagnosis and planning. This section explores the main findings of our study in the context of known anatomical trends, with particular attention to clinically significant patterns and deviations. The results of the study indicate that two-rooted teeth are the most common in mandibular third molars, while single- and three-rooted configurations occur much less frequently. Differences were observed between men and women in the frequency of root configurations; single-rooted teeth were more common in women, whereas two-rooted teeth were more common in men, although not all differences reached statistical significance. Vertucci type I canals were the most common in all root configurations; however, more complex canal types, including C-shaped canals, were also observed, particularly in single-rooted teeth and female patients. This study provides valuable insight into the structural complexity and variability of third molar morphology. Knowledge of root canal and root configurations can be improved through accurate CBCT imaging. In this study, mandibular third molars predominantly exhibited a two-rooted configuration (79.7%), consistent with the findings of many other studies (Sidow et al. , 2000; Gulabivala et al. , 2001, 2002; Sert et al. , 2011; Kuzekanani, Haghani and Nosrati, 2012; Ahmad et al. , 2016; Singh et al. , 2020; Al-Qudah et al. , 2023). Second most common root configuration was three rooted form (11.9%), and the least frequent was single rooted one (8.43%). No four rooted forms were found in our study, although in other studies they have been found (Sidow et al. , 2000; Gulabivala et al. , 2002; Sert et al. , 2011; Kuzekanani, Haghani and Nosrati, 2012; Ahmad et al. , 2016; Singh et al. , 2020; Al-Qudah et al. , 2023). The proportion of single-rooted teeth in the Polish population is lower than that observed in Turkish (24.8%) and Iranian (21%) samples, but significantly higher than in the Burmese population (0%). Comparing the prevalence of three roots in mandibular molars, which was 11.88% in our study, is closer to the 18% found in studies of the Indian population(Singh et al. , 2020) and higher than that reported in most studies (e.g., 5% in Sidow et al.(Sidow, West, Liewehr, et al. 2000)). In relation to sex differences, the occurrence of two rooted teeth was higher in males (87.3%) than in females (74.2%). In contrast to males, who only had 3.6% of one-rooted forms and 9.1% of three-rooted ones, females showed greater variation, with 11.9% of them being single-rooted and 13.9% three-rooted. These findings are in contrast to those of Jing et al. (Jing et al. , 2023), who found that the proportion of three-rooted molars was lower, and the prevalence of single-rooted molars was higher in both sexes. Similarly, significantly reduced percentages of mandibular third molars with single, double, and triple roots were reported by Somasundaram et al. (Somasundaram, 2017). These differences could be attributed to differences in demographic characteristics, imaging methods, or sample sizes. Therefore, it is essential to consider sex differences in future studies on mandibular third molars. A comparison of the prevalence of mandibular third molars with different root numbers from previous studies can be found in Supplement 2, while the sex-based distribution of MTMs in the present and previous studies is provided in Supplement 3. Moving towards root canal morphology, our study used Vertucci classification for recognition of root canal variations which is widely used, and well established among dental professionals(Vertucci, Seelig and Gillis, 1974). Newer classifications, by Weine (Weine et al. , 1969), and Sert and Bayirli (SERT and BAYIRLI, 2004), and Ahmed et al(Ahmed et al. , 2020), have been proposed, but they yet to be widely used. The studies we conducted took into account the division by sex in terms of root canal type. In two-rooted lower mandibular third teeth, Type I was more common in females and Type IV in males for mesial roots; however, these differences were not statistically significant. In both single- and double-rooted teeth, Type I predominated in females and males alike. There is only one study in the literature (Somasundaram, 2017) also distinguishes sex when describing root canals in the mesial roots of two-rooted teeth, where Type II predominates in both sexes; however, these results were also not statistically significant. This underscores the importance of including sex as a variable in future research. Overall, the findings of this study should be interpreted with caution. While the results confirm previously reported patterns of mandibular third molar morphology and provide new data for a Central European population, the limited sample size, single-region recruitment, and absence of sensitivity analyses restrict the generalizability of the conclusions. Taken together with the variability observed in other populations and across different methodologies, our results underscore the need for careful consideration when extrapolating these findings to broader clinical or research contexts. 4.1 Canal configurations To contextualize the findings, we reviewed relevant studies from the last decade. Efforts were made to compile and standardize findings from previous studies to facilitate a meaningful comparison with the results of the present study. The frequency of root canal configurations, the number of roots, population characteristics, and examination methods used in different studies were analysed and are summarized in the supplement 4. (Gulabivala et al. , 2001; Neelakantan, Subbarao and Subbarao, 2010; Drăgan et al. , 2016; Sun et al. , 2016; Somasundaram, 2017; Tomaszewska et al. , 2018; Hafezi, Sakhdari and Moaiyedmohseni, 2019; Naseri et al. , 2019; Shihab and Mahdee, 2021; Ahmed, 2022) 4.1.1 Single-Rooted MTMs In our study, Type I configurations were the most frequent in single-rooted teeth (40.9%), consistent with findings from Somasundaram (33.3%) and Priyank et al. (62.5%)(Somasundaram, 2017; Priyank et al. , 2023). Type IV (31.8%) and Type VIII (13.6%) also appeared with notable frequency, diverging from other reports where these types were relatively rare (Singh et al. , 2020). Configurations such as Types III, VI, VII, and non-classified forms were absent in our dataset. While Type II showed a modest yet consistent presence across studies, the prevalence of Type V varied considerably—from 18.8% in Al-Qudah et al. (2023) to near absence in others—suggesting potential influences from population-specific traits, anatomical variability, or methodological differences (Al-Qudah et al. , 2023). 4.1.2 Two-Rooted MTMs Focusing on two-rooted MTMs in a Polish population, our findings reveal a distinct distribution of canal configurations in mesial roots. Type I (63.9%) and Type IV (29.8%) were overwhelmingly dominant, while Types II, III, and V were rare and all other types absent. This contrasts sharply with Jordanian data: Ahmad et al. (2016) reported a more even distribution—Type I (40.6%), Type IV (28.1%), and a notable Type II presence (18.8%)(Ahmad et al. , 2016). Al-Qudah et al. (2023) found Type IV (44.8%) to be most common, followed by Types I, II, and minor variants (Types VI–VIII), none of which appeared in our sample. Indian studies further illustrate regional variability, with Priyank et al. (2023) reporting a high frequency of Type II (67.0%) and Type III (16.3%), while Somasundaram (2017) found similar trends(Al-Qudah et al. , 2023; Priyank et al. , 2023). These differences underscore the clear predominance of Types I and IV in the Polish sample, contrasting with the more diverse morphological profiles seen in Jordanian and Indian populations. In the distal roots of two-rooted MTMs, differences between populations were less pronounced. Our Polish sample showed a dominant Type I configuration (94.7%), closely aligning with findings from Ahmad et al. (93.8%) and Singh et al. (96.8%)(Ahmad et al. , 2016; Singh et al. , 2020). This consistency supports the notion that a single canal is the typical morphology in this root across populations. Minor variations were observed in secondary configurations: Type IV emerged as the second most common in our study (2.4%), whereas Indian studies noted a higher prevalence of Type II canals (Priyank: 11.0%; Somasundaram: 9.7%)(Somasundaram, 2017; Priyank et al. , 2023). Al-Qudah et al. (2023) also reported a relatively higher Type IV frequency (8.2%). Overall, the low incidence of complex canal systems in the Polish data emphasizes the predominance of simpler morphologies in the distal roots of MTMs(Al-Qudah et al. , 2023). 4.1.2.1 Fusion in Two-Rooted MTMs The present study identified 2 cases of MTMs with two fused roots, constituting 0.8% of all examined MTMs and 1% of two-rooted MTMs specifically. These findings stand in marked contrast to results published by Ahmad et al. and Al-Qudah, who reported substantially higher prevalence rates. According to these researchers, MTMs with fused roots constituted 28.6% and 9.9% of all examined third molars, respectively. Furthermore, when considering only the subset of two-rooted teeth, the prevalence of fusion reported by these authors reached 38.5% and 28.6%, respectively. This significant disparity in fusion prevalence between our study and previous research potentially indicates population-specific anatomical variations or criteria defining root fusion and show the necessity of standardizing nomenclature. 4.1.3 Challenges with Root Nomenclature and Anatomical Classification Previous research on mandibular third molar (MTM) root anatomy (Ahmad et al. , 2016; Somasundaram, 2017; Waheed Sharawy and Mohamed Aly Ahmed, 2017; Singh et al. , 2020; Priyank et al. , 2023) has consistently employed a directional nomenclature system utilizing the terms mesial, distal, and distolingual (M, D, DL) to identify distinct roots. However, this classification system appears problematic when evaluated against our findings. The nomenclature adopted by previous researchers suggests one of two scenarios: either all three-rooted MTMs in their studied populations present with two roots distally, or the majority of three-rooted MTMs in previously studied populations present with two roots distally, with researchers failing to distinguish cases where the third root was positioned lingually in a different location. Contrary to these classifications, our observations indicate that in three-rooted specimens, two roots are positioned in close proximity—either mesially or distally—with the majority exhibiting two roots on the mesial side. The naming convention utilized by Al-Qudah et al. also proves inadequate for describing the morphologies observed in our research. Their classification system identifies either a configuration of (M, D, L)—where "lingual" implies the third root's position can be clearly recognized as lingual, similar to maxillary molars—or configurations with two roots fused mesio-lingually or distally ((M, DL), D), ((D, DL), M), the first of which did not appear in our sample. We propose that this discrepancy stems from population differences. Notably, the present investigation represents the only such study conducted in Central European subjects, whereas previous research has focused on populations from India and Jordan. This anatomical reality challenges existing nomenclature and suggests the need for a revised classification system that accurately reflects the root distribution patterns observed across diverse populations. 4.1.4 Three-Rooted MTMs: Canal Configuration Patterns In the studied population, we identified 31 three-rooted mandibular third molars (MTMs), with 23 specimens presenting two mesial canals. When two mesial canals were present, they invariably exhibited a Type I configuration. In cases with a single mesial root, we documented Type I (75%) and Type IV (25%) canal configurations—findings that closely align with data reported from India (Priyank: Type I = 75%; Singh: Type I = 77.8%). Notably, other researchers have identified a broader spectrum of canal configurations (including Types II, III, and V) in the mesial root (Ahmad et al. , 2016; Somasundaram, 2017; Singh et al. , 2020; Al-Qudah et al. , 2023; Priyank et al. , 2023). Among the 23 cases of three-rooted MTMs with one distal root identified in our study, the Type I configuration predominated, with only a small proportion (4%) displaying Type IV morphology. We also documented 9 cases of MTMs with two distal roots. Regarding the distobuccal (DB) root specifically, there is a consistent prevalence of Type I canals across different studies. Our findings corroborate this pattern, highlighting the relative morphological consistency of the DB root. Although Somasundaram (2017) reported Type IV configuration in all four of their identified cases, such variations remain exceptional, suggesting a generally consistent morphological pattern (Somasundaram, 2017). In the distolingual (DL) root, Type I canals similarly predominate across most reports. While our study recorded one instance of Type V, and Priyank et al. (2023) noted a single occurrence of Type II, these variations remain uncommon (Ahmad et al. , 2016; Somasundaram, 2017; Waheed Sharawy and Mohamed Aly Ahmed, 2017; Singh et al. , 2020; Al-Qudah et al. , 2023; Priyank et al. , 2023) 4.1.4.1 Fusion and Rare Variations in Three-Rooted MTMs In addition to separate roots, three-rooted MTMs may present with fusion. Ahmad et al. (Ahmad et al. , 2016) and Al-Qudah et al. (Al-Qudah et al. , 2023) documented rare instances of three fused roots, which displayed either type VIII or a morphology that was not included in vertucci classification eg. (3 − 1, 3 − 2, 3–4, 2–3, 4 − 1, 4 − 2). Partial fusion, in which two roots are fused and the third remains distinct, also occurs in some populations. The most frequently observed scenario involves fusion of the mesial and disto-lingual roots, with the mesial root typically exhibiting Type IV canals and the distal root retaining a Type I pattern. There have also been two documented cases of fusion of distal and disto-lingual root. Additionally, two cases of fusion between the distal and disto-lingual roots have been documented (Al-Qudah et al. , 2023). In our study we did not encounter fused three rooted MTMs. 4.1.5 Extremely Rare Morphologies: Mandibular third molars (MTMs) with more than three roots are considered rare, and no such cases were found in the present study. A total of six MTMs with four roots were identified in the previous studies included in this comparison, all of which exhibited Type 1 canal systems. Additionally, two teeth with five roots were reported, presenting a variety of canal configurations. Remarkably there are case reports of successful treatment of such multi-rooted teeth (Plotino, 2008; Tomar et al. , 2013; Garg, Mantri and Agrawal, 2014; Sinha and Sinha, 2014; Jacob et al. , 2021). 4.1.6 Need for Standardization in Anatomical Reporting It is worth noting that a few inconsistencies were observed in some previously published datasets, particularly in the stratification of canal types by root position. While such discrepancies do not invalidate general trends, they highlight the need for improved standardization in future anatomical research. 4.2 C-shaped canal This study showed a 5.36% prevalence of C-shaped canals in the mandibular third molars, which when compared with earlier studies is more consistent with more recent studies than with earlier results. C-shaped canal was first observed by Cooke & Cox in 1979(Cooke and Cox, 1979). Study by Tomaszewska et al. (2018) (Tomaszewska et al. , 2018) showed only 0.8% of cases in her study. Newer study by Somasundaram et al. presented a 10.3% prevalence, predominantly in single-rooted MTMs —a pattern that closely matches the present study’s observation that over two-thirds of C-shaped canals occurred in single-rooted teeth. Furthermore, Priyank et al. (Priyank et al. , 2023) reported a slightly higher prevalence of C-shaped canals (7.58%) than in the current study. Present study showed a strong female predominance (92.86%) which has not been underlined in earlier studies, suggesting that future research may benefit from investigating the sex-related factors in C-shaped canal formation. These results suggest that the prevalence in the present study is higher than that reported in older data, but remains within the range of more recent observations, despite the ethnic differences between the Indian population studies conducted by Somasundaram (Somasundaram, 2017) and Priyank (Priyank et al. , 2023) and the Polish population studies in the present study. Taken together, these results reflect the evolving understanding of the prevalence and complexity of C-shaped canal morphology in mandibular third molars and emphasize the importance of both sample characteristics and diagnostic methodologies in estimating the prevalence. It is relevant to mention that the term “C-shaped” was used by the aforementioned authors to describe the shape of the canal, but it can also refer to the shape of the root. For example, Al-Quedah et al. use the term “C-shaped” to define a subtype of single-rooted teeth, distinguishing it from another type they describe as “conical.” In contrast, Ahmad et al. (2016) (Ahmad et al. , 2016) and Park et al. (2013) (Park et al. , 2013) use the term “C-shaped root” to describe teeth regardless of the number of roots. 4.3 Implications The findings of this study have significant clinical and academic implications. In clinical settings, endodontists typically work with limited imaging capabilities—usually restricted to 2D x-rays. While such imaging is of limited utility in detecting fine anatomical details of canal systems due to structural overlap, it generally permits accurate identification of root numbers. In such cases, the results of the present study provide valuable guidance, enabling clinicians to make informed predictions about potential canal configurations based on root number, as illustrated in Fig. 2 . The documented frequency distributions of root morphologies and canal configurations serve as a particularly valuable reference for anticipating the number and location of canal orifices. This knowledge can enhance procedural efficiency and reduce the risk of missed canals. Figure 4 illustrates the frequency of different numbers of canal orifices based on root number and their location. Beyond its direct medical uses, this research helps us better understand MTMs anatomy by adding to our knowledge of how MTM can vary in shape, showing important differences between populations when compared to past studies from other regions and emphasizing the need for thorough training in handling C-shaped canals since they are fairly common (5.36%) in our population. 4.4 Study limitations and future directions Among the limitations of our study, we must state that the sample size was limited, and the study population was chosen exclusively from the Lower Silesia region, which may not be a representative for broader populations. We could not use the small field of view CBCT images (5 × 5 cm) due to the limited number of cases, although they might have provided additional information about root canal anatomy. A small field of view is generally used by endodontists, but in our facility, full CBCT scans—or maxillary or mandibular CBCT scans—remain the most commonly performed. Regional genetic, and environmental factors could influence MTM morphology, hence limiting the generalizability of the findings to other populations. Given the single-region sample and specific demographic characteristics of the study group, the applicability of our results to broader populations or different clinical contexts should therefore be considered with caution. Although this study utilized CBCT for accurate assessment of root and canal morphology, its application in clinical practice is limited. Endodontists often depend on conventional periapical radiographs, which do not provide the same level of detail as CBCT scans. Consequently, translating the detailed anatomical findings from this study to routine endodontic practice may be challenging, as clinicians must infer 3D structures from 2D images. This discrepancy may affect the precision and the result of endodontic. A significant limitation affecting this and other anatomical studies is the absence of a standardization on the terminology and classification of root and canal anatomy. Variations in defining terms such as “separate roots”, "root bifurcation", and “root fusion” can make the direct comparisons between studies difficult. Since the study relied on the availability of CBCT scans, the sample may be biased toward individuals requiring imaging for clinical purposes (e.g., orthodontic treatment or oral surgery, or endodontic treatment). This may accidentally exclude individuals with no clinical need for CBCT imaging, thereby decreasing the representativeness of the sample. AI (artificial intelligence) usage to segment CBCT scans is a promising research direction. Traditional methods are time-consuming, and AI, especially deep learning models, can significantly improve the speed and accuracy of segmentation. This automation will streamline scan processing, enable analysis of larger samples, and improve the repeatability of studies by reducing observer bias. It is necessary to attempt to employ more heterogenous samples from different geographic regions to ensure that the results can be generalized to broader populations. The lack of a unified terminology and classification of root and canal anatomy remains a challenge. Future research should prioritize developing consistent definitions of terms such as “separate roots,” “root bifurcation,” and “root fusion” to facilitate direct comparisons between studies and to promote meta-analysis. We have to underline that CBCT is a practical compromise between resolution and accessibility, further studies could investigate the use of higher resolution imaging technologies such as micro-CT, which cannot be used in vivo, to more accurately visualize and classify complex root canal morphologies. Such imaging may provide a more advanced understanding of root canal systems. Further research is needed to reduce the differences between the details that can be detected in CBCT examinations when compared with standard X-ray images. 5. Conclusions This CBCT-based study provides new insight into the complex root and canal morphology of mandibular third molars (MTMs) in a Central European population. Two-rooted configurations were most common, regardless of sex, with clear differences in root morphology observed between sexes. Vertucci’s Type I canal system predominated across all root types, while C-shaped canals—though relatively uncommon—were significantly more frequent in female subjects and single-rooted MTMs. These findings have important clinical implications. They can assist endodontists in anticipating root canal anatomy based on root number and patient demographics, especially when CBCT is unavailable and clinicians must rely on 2D radiographs. The study also highlights the anatomical variability among populations and the need for tailored diagnostic approaches. Future research should aim to improve population diversity in anatomical studies, adopt consistent terminology, and explore the integration of AI-assisted CBCT analysis to enhance accuracy, efficiency, and reproducibility in root canal morphology assessment. Declarations Conflict of interest The authors declare no conflicts of interest related to this study. Funding This study was funded by Wrocław Medical University as part of the co-financing provided under the subsidy for maintaining and developing research potential in 2022 (SUBZ.B010.22.040). The funding source had no involvement in the study's design, data collection or analysis, decision to publish, or manuscript preparation. No additional external funding was received for this research. Ethics approval statement and document We hereby confirm that our work fully complies with the ethical requirements and policies specified by the journal. All research has been conducted in accordance with recognized ethical standards, and no part of the study violates the principles of integrity, transparency, or responsible authorship. All authors have contributed to the work, approved the final version of the manuscript, and agree with its submission. Declaration of generative AI and AI-assisted technologies in the writing process. During the preparation of this work the author(s) used OpenAi chatGPT in order to improve the readability and language of the manuscript and as an assisting tool during extraction and parsing of tabular data from other sources. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the published article. Data Availability Statement The data that support the findings of this study are available in Supplementary files under Supplement 5. Credit authorship contribution statement Anna Olczyk: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing – original draft, Validation, Writing -review & editing, Project administration Barbara Malicka: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing – original draft, Validation, Writing -review & editing, Project administration Paweł Stenzel: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing – original draft, Validation, Writing -review & editing, Project administration Urszula Sękowska: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing – original draft, Validation, Writing -review & editing, Project administration Katarzyna Skośkiewicz - Malinowska: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing – original draft, Validation, Writing -review & editing, Project administration, Funding acquisition. 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Clinical Anatomy. https://doi.org/10.1002/ca.22800 Vertucci, F., Seelig, A., Gillis, R., 1974. Root canal morphology of the human maxillary second premolar. Oral Surgery, Oral Medicine, Oral Pathology 38, 456–464. https://doi.org/10.1016/0030-4220(74)90374-0 von Elm, E., Altman, D.G., Egger, M., Pocock, S.J., Gøtzsche, P.C., Vandenbroucke, J.P., 2008. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. J Clin Epidemiol 61, 344–349. https://doi.org/10.1016/j.jclinepi.2007.11.008 Waheed Sharawy, W., Mohamed Aly Ahmed, H., 2017. Case Report Endodontic Management of a Three Rooted Mandibular Third Molar with a Dilacerated Distal Root and Close Approximation to the Inferior Alveolar Canal: A Case Report 7. https://doi.org/10.5577/intdentres Weine, F.S., Healey, H.J., Gerstein, H., Evanson, L., 1969. Canal configuration in the mesiobuccal root of the maxillary first molar and its endodontic significance. Oral Surgery, Oral Medicine, Oral Pathology 28, 419–425. https://doi.org/10.1016/0030-4220(69)90237-0 Yang, L., Han, J., Wang, Q., Wang, Z., Yu, X., Du, Y., 2022. Variations of root and canal morphology of mandibular second molars in Chinese individuals: a cone-beam computed tomography study. BMC Oral Health 22, 274. https://doi.org/10.1186/s12903-022-02299-8 Additional Declarations No competing interests reported. Supplementary Files Supplement1.docx Supplement 1- AQUA Checklist Supplement2.docx Supplement 2 - Prevalence of mandibular third molars with different root numbers in previous studies and the present one. Data adapted from Al-Qudah et al., 2023 licensed under Creative Commons Attribution 4.0 International License Supplement3.docx Supplement 3 - Sex-based distribution of MTMs in the present and previous studies Supplement4.xlsx Supplement 4 - Root canal configurations of MTMs with Different Root Numbers in the Present Study and Previous Studies Supplement5.xlsx Supplement 5 – Data supporting study, according to data availability statement Supplement6.docx Supplement 6 - STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) Checklist Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 25 Mar, 2026 Reviews received at journal 21 Feb, 2026 Reviews received at journal 17 Feb, 2026 Reviewers agreed at journal 15 Feb, 2026 Reviews received at journal 13 Feb, 2026 Reviewers agreed at journal 10 Feb, 2026 Reviewers agreed at journal 10 Feb, 2026 Reviewers agreed at journal 04 Feb, 2026 Reviewers invited by journal 04 Feb, 2026 Editor invited by journal 15 Dec, 2025 Editor assigned by journal 12 Dec, 2025 Submission checks completed at journal 12 Dec, 2025 First submitted to journal 04 Dec, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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University","correspondingAuthor":false,"prefix":"","firstName":"Katarzyna","middleName":"Skośkiewicz","lastName":"-Malinowska","suffix":""}],"badges":[],"createdAt":"2025-12-04 21:38:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8282672/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8282672/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102210596,"identity":"82ceb697-48c9-491e-b198-fb60e3315edc","added_by":"auto","created_at":"2026-02-09 12:21:33","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":55147,"visible":true,"origin":"","legend":"\u003cp\u003eExclusion criteria (STROBE Flowchart)\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/67ebcf9aca0a512809f8f774.jpg"},{"id":102210598,"identity":"7aad75e1-ecdb-4283-ad86-5420b65884e5","added_by":"auto","created_at":"2026-02-09 12:21:33","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":81976,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution of Vertucci Canal Configurations by Root Morphology Distribution of Vertucci Canal Configurations by Root Morphology\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/6da6cb1fffb2e3a528abaf42.jpg"},{"id":102210597,"identity":"8c9b6fb3-bce7-47dc-b6a5-eea34715418f","added_by":"auto","created_at":"2026-02-09 12:21:33","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":25240,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution of C-shaped Canals by Gender\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/9db16dcf7f61b93be9fd002f.jpg"},{"id":102301651,"identity":"67514b9b-1e72-44b9-8554-197b3a17d6db","added_by":"auto","created_at":"2026-02-10 11:22:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1384171,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/1519aacb-7a20-4307-a832-def548f0ca08.pdf"},{"id":102296774,"identity":"6f173199-f836-4661-a8a5-101b417d6e17","added_by":"auto","created_at":"2026-02-10 10:21:34","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":44209,"visible":true,"origin":"","legend":"\u003cp\u003eSupplement 1- AQUA Checklist\u003c/p\u003e","description":"","filename":"Supplement1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/af6ffda9e483a622e1b16f7f.docx"},{"id":102297045,"identity":"3af651a2-bfab-48d9-8788-2e3c551026c3","added_by":"auto","created_at":"2026-02-10 10:25:18","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":16454,"visible":true,"origin":"","legend":"\u003cp\u003eSupplement 2 - Prevalence of mandibular third molars with different root numbers in previous studies and the present one. Data adapted from Al-Qudah et al., 2023 licensed under Creative Commons Attribution 4.0 International License\u003c/p\u003e","description":"","filename":"Supplement2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/77717efee9f6f7b400f0ee02.docx"},{"id":102210603,"identity":"e09e8c77-2d22-4ba2-8d1c-2cfdf04c0161","added_by":"auto","created_at":"2026-02-09 12:21:33","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":18943,"visible":true,"origin":"","legend":"\u003cp\u003eSupplement 3 - Sex-based distribution of MTMs in the present and previous studies\u003c/p\u003e","description":"","filename":"Supplement3.docx","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/2e48e4fae82504c1ace4d5cd.docx"},{"id":102210601,"identity":"49ebf3b6-8fb3-463a-8ba1-d794ecb6e398","added_by":"auto","created_at":"2026-02-09 12:21:33","extension":"xlsx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":22561,"visible":true,"origin":"","legend":"\u003cp\u003eSupplement 4 - Root canal configurations of MTMs with Different Root Numbers in the Present Study and Previous Studies\u003c/p\u003e","description":"","filename":"Supplement4.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/140c7622a0b4c8730d7e530b.xlsx"},{"id":102210604,"identity":"e558d3d5-d427-4f8c-b596-4789866f3589","added_by":"auto","created_at":"2026-02-09 12:21:33","extension":"xlsx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":83190,"visible":true,"origin":"","legend":"\u003cp\u003eSupplement 5 – Data supporting study, according to data availability statement\u003c/p\u003e","description":"","filename":"Supplement5.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/1625c0d3b68b66180d87658a.xlsx"},{"id":102297156,"identity":"1fc8c0a4-2021-4076-a38f-a9f9e36bef4a","added_by":"auto","created_at":"2026-02-10 10:26:09","extension":"docx","order_by":6,"title":"","display":"","copyAsset":false,"role":"supplement","size":43743,"visible":true,"origin":"","legend":"\u003cp\u003eSupplement 6 - STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) Checklist\u003c/p\u003e","description":"","filename":"Supplement6.docx","url":"https://assets-eu.researchsquare.com/files/rs-8282672/v1/6861c732f40b284b518e5241.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Morphology of Third Mandibular Molars – An In Vivo Cone Beam Computed Tomography Study in Lower Silesia","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eMandibular third molars (MTMs), commonly referred to as wisdom teeth, exhibit significant anatomical variability, posing challenges for dental practitioners in endodontic and surgical procedures. Accurate knowledge of root canal morphology is essential for effective treatment planning and achieving successful clinical outcomes.\u003c/p\u003e \u003cp\u003eAlthough numerous studies have investigated the anatomy of mandibular first (Al-Habib \u003cem\u003eet al.\u003c/em\u003e, 2024) and second molars (Yang \u003cem\u003eet al.\u003c/em\u003e, 2022), research focusing specifically on mandibular third molars remains limited (Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023). Notably, to date, only one study has examined MTMs in the Polish population (Tomaszewska \u003cem\u003eet al.\u003c/em\u003e, 2018).\u003c/p\u003e \u003cp\u003eUnderstanding the anatomical complexity of MTMs is critical for successful endodontic treatment. Beyond their functional role, MTMs can also serve important purposes when opposing teeth are absent, such as acting as fixed prosthetic abutments, providing support for partial dentures, or being used for autotransplantation (De Bruyn \u003cem\u003eet al.\u003c/em\u003e, 2020).\u003c/p\u003e \u003cp\u003eCurrent research on root canal configurations on MTMs reveals several gaps. Many studies lack population diversity, which limits the generalizability of findings to other groups.(Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016; Somasundaram, 2017; Tomaszewska \u003cem\u003eet al.\u003c/em\u003e, 2018; Singh \u003cem\u003eet al.\u003c/em\u003e, 2020; Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023). Additionally, the absence of standardized terminology and classification systems makes direct comparisons across studies difficult. Inconsistencies in data presentation, limited statistical analyses, small sample sizes, and insufficient stratification further reduce the reliability and applicability of existing findings.\u003c/p\u003e \u003cp\u003eIn this study, the root canal morphology of the MTM was investigated in a population from Lower Silesia using CBCT imaging. Lower Silesia is designated as the PL5 region under the Nomenclature of Territorial Units for Statistics (NUTS), with its capital in Wrocław (PL514). The research question was what is the most common configuration of the root canal system in the mandibular third molars (MTM).\u003c/p\u003e \u003cp\u003eThe use of cone-beam computed tomography (CBCT) in this study is well-justified based mainly on its balance of accuracy, accessibility, and clinical applicability. While micro-computed tomography (micro-CT) offers higher resolution, it could not be used in vivo due to high radiation exposure (Ahmed, 2022). In contrast, CBCT provides three-dimensional imaging with sufficient detail for clinical research and is widely available, making it both practical and ethical for human studies (Neelakantan, Subbarao and Subbarao, 2010; Naseri \u003cem\u003eet al.\u003c/em\u003e, 2019)\u003c/p\u003e \u003cp\u003eAlthough clearing and staining have historically been considered the gold standard, CBCT has shown comparable accuracy (Drăgan, Fărcăşanu, C\u0026acirc;mpian, et al. 2016; Shihab \u0026amp; Mahdee 2021). CBCT also allows for larger sample sizes than staining methods, increasing statistical power and generalizability (Sun \u003cem\u003eet al.\u003c/em\u003e, 2016). Despite some resolution limitations, CBCT offers a reliable, non-invasive method for root canal analysis and is currently one of the best options for clinical use.\u003c/p\u003e \u003cp\u003eThis study investigates the root canal morphology of MTMs in a population from Lower Silesia using CBCT imaging. Specifically, it addresses the following questions:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eHow many roots are most commonly present in mandibular third molars (MTMs)?\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAre there significant differences in the number of roots in MTMs between males and females?\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eWhat are the most common root canal configurations in mandibular third molars?\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eWhat is the prevalence of C-shaped root canals in MTMs?\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eTo address these objectives, CBCT scans of MTMs were analysed, classifying root and canal systems based on Vertucci\u0026rsquo;s system and assessing sex-based variations. Furthermore, this study aims to comprehensively compare its findings to existing literature to contribute to a deeper understanding of MTM morphology.\u003c/p\u003e"},{"header":"2. Material and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Data Collection\u003c/h2\u003e \u003cp\u003eThe study was designed and reported in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines(von Elm \u003cem\u003eet al.\u003c/em\u003e, 2008). The CBCT scans were obtained from the Academic Dental Polyclinic of (city name anonymized due to double blind policy) Medical University in Poland, specifically from the X-Ray Diagnostic Laboratory. These scans were conducted for diagnostic or other dental purposes between January and April 2022 using a Rayscan α-Plus 130 (Rayscan 700) CBCT scanner (Ray Europe GmbH, Seoul, South Korea). The scanner's specifications included a field of view ranging from 3x4 cm to 13x10 cm, with settings of 60\u0026ndash;90 kV, 4\u0026ndash;17 mA, a scan duration of 14 seconds, and voxel sizes of 70 \u0026micro;m, 160 \u0026micro;m, 200 \u0026micro;m, or 280 \u0026micro;m. The slice thickness varied from 0.07 mm to 3 mm.\u003c/p\u003e \u003cp\u003eTo standardize the study, full-mouth CBCT scans with a voxel size of 160 \u0026micro;m, slice thickness of 0.16 mm, field of view of 13x10 cm, and settings of 90 kV and 4 mA were used. Data were reviewed using Rayscan SMART Dent software (Ray Co., Ltd, Seoul, South Korea) and OnDemand3DApp software (Cyber Med, Seoul, South Korea). Research access to the data was granted on June 7, 2022. Study approval was obtained from the Bioethics Committee of (city name anonymized due to double blind policy) Medical University (approval no. KB 206/2022), in accordance with the Declaration of Helsinki.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eInformed consent\u003c/strong\u003e \u003cp\u003ewas obtained, and data were anonymized to ensure that participants could not be identified. Following the analysis of 316 CBCT scans from a potential total of 632 teeth, 261 mandibular third molars met the inclusion criteria. The images were evaluated by two endodontists with 5 and 30 years of professional experience, respectively. Disagreements were resolved through consensus. A Beacon Display C25W screen (Shenzhen Beacon Display Technology Co., Ltd.) was used for analysis, featuring a resolution of 1920 x 1080 pixels. Various image adjustments, including zoom, magnification, brightness, and contrast, were applied as needed. Assessments were performed in a dimly lit room, with no more than 15 scans evaluated per session to minimize fatigue.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eInclusion criteria were: participants aged 18 or older (continuous variable, with no further categorization); teeth without caries, fillings, prosthetic crowns, or post-core inlays; teeth without previous endodontic treatment; teeth with closed apices, free from resorptions or calcifications; and artifact-free CBCT images. Tooth rotation (mesiolingual or distolingual) did not disqualify the tooth from the study.\u003c/p\u003e \u003cp\u003eThe number of roots, root canals, and root canal configurations were assessed according to Vertucci's classification (1974) (Vertucci, Seelig and Gillis, 1974), which categorizes root canal morphology into eight distinct types (I-VIII) based on the number and configuration of canals from the pulp chamber to the apex, representing specific patterns of how canals may branch, merge, or remain separate throughout the root. Root and root canal number were treated as categorical variables.\u003c/p\u003e \u003cp\u003eIt must be noted that some canal anatomy variations are impossible to describe using this method, so some authors proposed the expansion of this classification to include several other canal configurations (Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023; Gulabivala and Ng, 2023). Recently new system has been proposed, and it remains to be seen whether it will see wider implementation (Ahmed \u003cem\u003eet al.\u003c/em\u003e, 2017).\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eVertucci's classification delineates root canal configurations as follows:\u003c/p\u003e\u003cp\u003eType I \u0026ndash; single canal from the pulp chamber to the apex of the root\u003c/p\u003e\u003cp\u003eType II \u0026ndash; two canals exit the pulp chamber and join into one canal to the apex of the root\u003c/p\u003e\u003cp\u003eType III \u0026ndash; single canal leaves the pulp to divide into two and then join again and finish at the apex of the root\u003c/p\u003e\u003cp\u003eType IV \u0026ndash; two canals leave the pulp chamber and two canals continue to the apex\u003c/p\u003e\u003cp\u003eType V \u0026ndash; single canal leaves the pulp chamber and divides into two canals that continue to the apex\u003c/p\u003e\u003cp\u003eType VI \u0026ndash; two canals leave the pulp chamber, then merge into one and divide into two again and finish as to canals to the apex\u003c/p\u003e\u003cp\u003eType VII \u0026ndash; single canal leaves the pulp chamber, then divides into two, then merges into one to finally divide into two canals and finish as two canals at the apex\u003c/p\u003e\u003cp\u003eType VIII \u0026ndash; three canals leave the pulp chamber, and three canals exit to the apex.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eBefore evaluating the CBCT scans, both endodontists underwent training and calibration using sample CBCTs representing the eight types of Vertucci's classification. Cohen's kappa statistic was calculated to evaluate interobserver agreement, yielding a value of 91.7%, indicating excellent agreement ((McHugh, 2012).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Statistical Analysis\u003c/h2\u003e \u003cp\u003eData analysis was conducted by the Statistical Analysis Center of (city name anonymized due to double blind policy) Medical University using Statistica 13 (2017) software (TIBCO Software Inc., USA). The analysis included the number of roots (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), the number of roots by sex (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), and Vertucci\u0026rsquo;s classification (Tables\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and \u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents chi-squared and p-values comparing the frequency of each tooth type by sex. The chi-squared test yielded a significance level below 0.05 (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The Bonferroni correction was applied to control for Type I error, adjusting for incidental findings of significant differences. The threshold for statistical significance was set at 0.05. Confidence intervals for the observed rates are provided in Tables\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and 6.\u003c/p\u003e \u003cp\u003eAll available scans (n\u0026thinsp;=\u0026thinsp;316) were analysed, and the power of the analysis for mandibular third molars meeting the inclusion criteria (n\u0026thinsp;=\u0026thinsp;261) was calculated afterwards using the \u0026ldquo;power.chisq.test\u0026rdquo; function from the \u0026ldquo;DescTools\u0026rdquo; R package. The chi-squared test on 2x4 tables indicated that a sample size of 261 allows for the detection of Cohen\u0026rsquo;s effect size \u0026ldquo;w\u0026rdquo; of 0.172 with a power of 0.64 and an alpha level of 0.05 (two-tailed test). A power of 0.64 means there is a 64% probability of detecting an effect size of 0.172 if it truly exists. This suggests a reasonable chance of detecting a small to medium effect, though there is still a 36% chance of failing to detect an effect if it is present. According to Cohen\u0026rsquo;s classification, an effect size of w\u0026thinsp;=\u0026thinsp;0.172 is considered between \u0026ldquo;small\u0026rdquo; (0.1) and \u0026ldquo;medium\u0026rdquo; (0.3).\u003c/p\u003e \u003cp\u003eControl for confounding was addressed by inclusion criteria, no additional statistical adjustment for confounding was applied. Only artifact-free CBCT images were included; as a result, no missing data were present in the analyses. All available scans meeting the inclusion criteria were analyzed; no complex sampling strategy was applied, and hence no analytical methods to account for sampling design were required. Sensitivity analyses were not applicable in this study.\u003c/p\u003e \u003cp\u003eThe study adhered to the guidelines outlined in the Anatomical Quality Assurance (AQUA) checklist (Tomaszewski \u003cem\u003eet al.\u003c/em\u003e, 2017) attached in supplement 1.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Characteristics of the Study Population\u003c/h2\u003e \u003cp\u003eOut of an initial set of 632 potential teeth, 316 CBCT scans were analysed. From these, 261 mandibular third molars were selected for evaluation. These teeth came from 151 females (57.9%) and 110 males (42.1%). The absence of the mandibular third molar, the exclusion of the area of examination, and the patient's age were the main reasons for excluding teeth from the study group. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the inclusion and exclusion criteria for the study.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Root Count (overall)\u003c/h2\u003e \u003cp\u003eOut of the 261 teeth scans analysed, two-rooted teeth were the most prevalent, accounting for 79.69% (n\u0026thinsp;=\u0026thinsp;208). Three-rooted teeth were less common, at 11.81% (n\u0026thinsp;=\u0026thinsp;31), and single-rooted teeth were the least common, making up 8.43% (n\u0026thinsp;=\u0026thinsp;22) (see Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, Chart \u003cspan refid=\"Str1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDistribution (%) of roots in mandibular third molars with 95% confidence intervals (CI)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNumber of roots\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eProportion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(0.05; 0.12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e208\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e79.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(0.74; 0.84)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(0.08; 0.16)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e261\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e100.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Root Count by Sex\u003c/h2\u003e \u003cp\u003eThe frequency of occurrence of various mandibular third molar types, categorized by the number of roots, was also evaluated based on patient sex (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOur research revealed that single-rooted mandibular third molars were more prevalent in females compared to males, with 18 teeth (11.92%) in females versus 4 teeth (3.64%) in males, and it was not statistically significant, p\u0026thinsp;=\u0026thinsp;0.051. Two-rooted forms of mandibular third molars were significantly more common in females than in males, and it was statistically significant (112 teeth, 74.17% vs 96 teeth, 87.27%, p\u0026thinsp;=\u0026thinsp;0.027) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Three-rooted teeth occurred more frequently in females (21 teeth, 13.91%) than in males (10 teeth, 9.09%), but the difference was also statistically insignificant (p\u0026thinsp;=\u0026thinsp;0.705).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDistribution (%) of roots in mandibular third molars based on sex\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNumber of roots\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eChi-square statistic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e7.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003e0.02\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e112\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e74.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e87.27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9.09\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e151\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e110\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003e\u003cem\u003eStatistical significance threshold set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eA post hoc test of the differences in the frequency of roots between the sexes (females vs. males) in maxillary third molars with Bonferroni correction\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComparison\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eChi-square statistic\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e1-root vs. others\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.051\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e2-root vs. others\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0.027\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e3-root vs. others\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.705\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eStatistical significance threshold set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Root Canal Configurations by Root Count\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e illustrates the distribution of Vertucci canal configurations across the diverse root morphologies observed in this study. This visualization highlights several key trends. Notably, Type I canal configurations are dominant across all root categories, suggesting a fundamental pattern in root canal anatomy. Overall, the most frequently occurring Vertucci types, in descending order, are: I\u0026thinsp;\u0026gt;\u0026thinsp;IV\u0026thinsp;\u0026gt;\u0026thinsp;V\u0026thinsp;\u0026gt;\u0026thinsp;III\u0026thinsp;\u0026gt;\u0026thinsp;II\u0026thinsp;\u0026gt;\u0026thinsp;VIII. The chart also reveals a higher frequency of two canals (corresponding to Type IV configurations) in the mesial roots compared to distal ones. For a more detailed, quantitative analysis, Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e presents the frequency and percentage of each Vertucci configuration within the categorized root morphology groups. Furthermore, Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e complements this data by providing 95% confidence intervals for the proportions of each Vertucci type within these root morphologies, offering a measure of statistical precision.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e3.4.1 Single-rooted Teeth\u003c/h2\u003e \u003cp\u003eSingle-rooted teeth predominantly exhibited Type I root canals according to Vertucci\u0026rsquo;s classification, with 9 teeth (40.91%) identified as such. Type IV canals were less common, observed in 7 teeth (31.82%). Types III, VI, and VII were absent from the study group, while Type VIII (3 teeth, 13.64%) was found infrequently. Similarly, Types II (2 teeth, 9.09%) and V (1 tooth, 4.55%) were observed sporadically.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e3.4.2 Two-rooted Teeth\u003c/h2\u003e \u003cp\u003eIn two-rooted mandibular third molars, Vertucci\u0026rsquo;s Type I root canal configuration was the most frequently observed in both mesial (133 teeth, 64.42%) and distal (197 teeth, 94.71%) roots. Type IV was also relatively common in the mesial roots, occurring in 62 teeth (29.81%). Types II (8 teeth, 3.85%), III (2 teeth, 0.96%), and V (3 teeth, 1.44%) were also identified. In distal roots, Types II (4 teeth, 1.92%), IV (5 teeth, 2.40%), VI (1 tooth, 0.48%), and VIII (1 tooth, 0.48%) appeared sporadically. Among all the teeth examined, there were only 2 cases of fused roots, and those were among 2 rooted teeth. Two cases of fused roots were observed in two-rooted mandibular third molars, both in female patients, exhibiting Type I canal configurations in distal roots and Type I or Type V configurations in mesial roots.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e3.4.3 Three-rooted Teeth\u003c/h2\u003e \u003cp\u003eThree-rooted teeth exhibited two root configurations. In the first, roots were mesiobuccal (MB), mesiolingual (ML), and distal (D), while in the second, roots were mesial (M), distobuccal (DB), and distolingual (DL). In both configurations, the most common Vertucci classification type was Type I. Types IV and V were less common, with Type IV found in mesial and distal roots, and Type V found in the distolingual root. No teeth with root fusion were identified among three-rooted.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eVertucci's canal classification in the studied population\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"7\" nameend=\"c9\" namest=\"c3\"\u003e \u003cp\u003eVertucci\u0026rsquo;s canal types\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of roots\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRoot\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eII\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIII\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eIV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eVI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eVIII\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (40.91)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (9.09)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7 (31.82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1 (4.55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3 (13.64)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e133 (64.42)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8 (3.85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2 (0.96)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e62 (29.81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3 (1.44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e80/53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25/37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e197 (94.71)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (1.92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5 (2.40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1 (0.48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1 (0.48)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e106/91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0/1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 (MB, ML, D)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23 (100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14/9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eML\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23 (100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14/9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (95.65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1 (4.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13/9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 (M, DB, DL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (75.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2 (25.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (87.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1 (12.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efemale/male\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePercentages (in relation to the total number of canal types) along with their 95% confidence intervals (CI)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"15\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNumber of roots\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eRoot\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTotal number\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"12\" nameend=\"c15\" namest=\"c4\"\u003e \u003cp\u003eVertucci\u0026rsquo;s canal types\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eType I\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eType II\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eType III\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eType IV\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003eType V\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c14\"\u003e \u003cp\u003eType VIII\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eProportion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eProportion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eProportion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eProportion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eProportion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eProportion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.207;\u003c/p\u003e \u003cp\u003e0.637\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.011; 0.292\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.139; 0.549\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e0.001; 0.228\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e0.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.029;\u003c/p\u003e \u003cp\u003e0.349\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e208\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.570; 0.705\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.017; 0.074\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.001; 0.034\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.237; 0.365\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e0.001;\u003c/p\u003e \u003cp\u003e0.034\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e208\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.913;\u003c/p\u003e \u003cp\u003e0.978\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.005; 0.049\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.005; 0.049\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eML\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.781; 0.999\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.001; 0.220\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.349; 0.9681\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.032; 0.651\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.474; 0.997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e0.003; 0.527\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.5 C-shaped canals\u003c/h2\u003e \u003cp\u003eC-shaped canals were observed in 5.36% of cases (14 teeth), predominantly in females (13 teeth, 92.86%) compared to males (1 tooth, 7.14%). These canals were found in both single-rooted (10 teeth, 71.43%) and double-rooted (4 teeth, 28.57%) teeth. The only C-shaped canal identified in a male patient was in a single-rooted tooth. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e presents a pie chart illustrating the distribution of C-shaped canals by sex, highlighting their higher prevalence in females, while other canal morphologies constitute the remaining portion of the sample.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eOnly unadjusted estimates were presented. No confounder-adjusted analyses were performed beyond restriction by inclusion criteria. Precision of estimates was expressed with 95% confidence intervals. Age was recorded as a continuous variable with an inclusion threshold of 18 years; no further categorization was applied. Relative and absolute risk estimates were not applicable in this morphological study.\u003c/p\u003e \u003cp\u003eSubgroup analyses were performed by sex for the number of roots and root canal configurations. Post hoc comparisons with Bonferroni correction were conducted to assess differences between male and female participants. No interaction analyses or sensitivity analyses were performed\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eMandibular third molars (MTMs) often present with considerable anatomical variability, making them a frequent source of clinical uncertainty in endodontics. Thorough understanding of their morphology is essential not only for successful treatment, but also for avoiding complications during diagnosis and planning. This section explores the main findings of our study in the context of known anatomical trends, with particular attention to clinically significant patterns and deviations.\u003c/p\u003e \u003cp\u003eThe results of the study indicate that two-rooted teeth are the most common in mandibular third molars, while single- and three-rooted configurations occur much less frequently. Differences were observed between men and women in the frequency of root configurations; single-rooted teeth were more common in women, whereas two-rooted teeth were more common in men, although not all differences reached statistical significance. Vertucci type I canals were the most common in all root configurations; however, more complex canal types, including C-shaped canals, were also observed, particularly in single-rooted teeth and female patients. This study provides valuable insight into the structural complexity and variability of third molar morphology. Knowledge of root canal and root configurations can be improved through accurate CBCT imaging.\u003c/p\u003e \u003cp\u003eIn this study, mandibular third molars predominantly exhibited a two-rooted configuration (79.7%), consistent with the findings of many other studies (Sidow \u003cem\u003eet al.\u003c/em\u003e, 2000; Gulabivala \u003cem\u003eet al.\u003c/em\u003e, 2001, 2002; Sert \u003cem\u003eet al.\u003c/em\u003e, 2011; Kuzekanani, Haghani and Nosrati, 2012; Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016; Singh \u003cem\u003eet al.\u003c/em\u003e, 2020; Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023). Second most common root configuration was three rooted form (11.9%), and the least frequent was single rooted one (8.43%). No four rooted forms were found in our study, although in other studies they have been found (Sidow \u003cem\u003eet al.\u003c/em\u003e, 2000; Gulabivala \u003cem\u003eet al.\u003c/em\u003e, 2002; Sert \u003cem\u003eet al.\u003c/em\u003e, 2011; Kuzekanani, Haghani and Nosrati, 2012; Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016; Singh \u003cem\u003eet al.\u003c/em\u003e, 2020; Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023). The proportion of single-rooted teeth in the Polish population is lower than that observed in Turkish (24.8%) and Iranian (21%) samples, but significantly higher than in the Burmese population (0%). Comparing the prevalence of three roots in mandibular molars, which was 11.88% in our study, is closer to the 18% found in studies of the Indian population(Singh \u003cem\u003eet al.\u003c/em\u003e, 2020) and higher than that reported in most studies (e.g., 5% in Sidow et al.(Sidow, West, Liewehr, et al. 2000)).\u003c/p\u003e \u003cp\u003eIn relation to sex differences, the occurrence of two rooted teeth was higher in males (87.3%) than in females (74.2%). In contrast to males, who only had 3.6% of one-rooted forms and 9.1% of three-rooted ones, females showed greater variation, with 11.9% of them being single-rooted and 13.9% three-rooted. These findings are in contrast to those of Jing et al. (Jing \u003cem\u003eet al.\u003c/em\u003e, 2023), who found that the proportion of three-rooted molars was lower, and the prevalence of single-rooted molars was higher in both sexes. Similarly, significantly reduced percentages of mandibular third molars with single, double, and triple roots were reported by Somasundaram et al. (Somasundaram, 2017). These differences could be attributed to differences in demographic characteristics, imaging methods, or sample sizes. Therefore, it is essential to consider sex differences in future studies on mandibular third molars.\u003c/p\u003e \u003cp\u003eA comparison of the prevalence of mandibular third molars with different root numbers from previous studies can be found in Supplement 2, while the sex-based distribution of MTMs in the present and previous studies is provided in Supplement 3.\u003c/p\u003e \u003cp\u003eMoving towards root canal morphology, our study used Vertucci classification for recognition of root canal variations which is widely used, and well established among dental professionals(Vertucci, Seelig and Gillis, 1974). Newer classifications, by Weine (Weine \u003cem\u003eet al.\u003c/em\u003e, 1969), and Sert and Bayirli (SERT and BAYIRLI, 2004), and Ahmed et al(Ahmed \u003cem\u003eet al.\u003c/em\u003e, 2020), have been proposed, but they yet to be widely used. The studies we conducted took into account the division by sex in terms of root canal type. In two-rooted lower mandibular third teeth, Type I was more common in females and Type IV in males for mesial roots; however, these differences were not statistically significant. In both single- and double-rooted teeth, Type I predominated in females and males alike. There is only one study in the literature (Somasundaram, 2017) also distinguishes sex when describing root canals in the mesial roots of two-rooted teeth, where Type II predominates in both sexes; however, these results were also not statistically significant. This underscores the importance of including sex as a variable in future research.\u003c/p\u003e \u003cp\u003eOverall, the findings of this study should be interpreted with caution. While the results confirm previously reported patterns of mandibular third molar morphology and provide new data for a Central European population, the limited sample size, single-region recruitment, and absence of sensitivity analyses restrict the generalizability of the conclusions. Taken together with the variability observed in other populations and across different methodologies, our results underscore the need for careful consideration when extrapolating these findings to broader clinical or research contexts.\u003c/p\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Canal configurations\u003c/h2\u003e \u003cp\u003eTo contextualize the findings, we reviewed relevant studies from the last decade. Efforts were made to compile and standardize findings from previous studies to facilitate a meaningful comparison with the results of the present study. The frequency of root canal configurations, the number of roots, population characteristics, and examination methods used in different studies were analysed and are summarized in the supplement 4. (Gulabivala \u003cem\u003eet al.\u003c/em\u003e, 2001; Neelakantan, Subbarao and Subbarao, 2010; Drăgan \u003cem\u003eet al.\u003c/em\u003e, 2016; Sun \u003cem\u003eet al.\u003c/em\u003e, 2016; Somasundaram, 2017; Tomaszewska \u003cem\u003eet al.\u003c/em\u003e, 2018; Hafezi, Sakhdari and Moaiyedmohseni, 2019; Naseri \u003cem\u003eet al.\u003c/em\u003e, 2019; Shihab and Mahdee, 2021; Ahmed, 2022)\u003c/p\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003ch2\u003e4.1.1 Single-Rooted MTMs\u003c/h2\u003e \u003cp\u003eIn our study, Type I configurations were the most frequent in single-rooted teeth (40.9%), consistent with findings from Somasundaram (33.3%) and Priyank et al. (62.5%)(Somasundaram, 2017; Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023). Type IV (31.8%) and Type VIII (13.6%) also appeared with notable frequency, diverging from other reports where these types were relatively rare (Singh \u003cem\u003eet al.\u003c/em\u003e, 2020). Configurations such as Types III, VI, VII, and non-classified forms were absent in our dataset. While Type II showed a modest yet consistent presence across studies, the prevalence of Type V varied considerably\u0026mdash;from 18.8% in Al-Qudah et al. (2023) to near absence in others\u0026mdash;suggesting potential influences from population-specific traits, anatomical variability, or methodological differences (Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e4.1.2 Two-Rooted MTMs\u003c/h2\u003e \u003cp\u003eFocusing on two-rooted MTMs in a Polish population, our findings reveal a distinct distribution of canal configurations in mesial roots. Type I (63.9%) and Type IV (29.8%) were overwhelmingly dominant, while Types II, III, and V were rare and all other types absent. This contrasts sharply with Jordanian data: Ahmad et al. (2016) reported a more even distribution\u0026mdash;Type I (40.6%), Type IV (28.1%), and a notable Type II presence (18.8%)(Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016). Al-Qudah et al. (2023) found Type IV (44.8%) to be most common, followed by Types I, II, and minor variants (Types VI\u0026ndash;VIII), none of which appeared in our sample. Indian studies further illustrate regional variability, with Priyank et al. (2023) reporting a high frequency of Type II (67.0%) and Type III (16.3%), while Somasundaram (2017) found similar trends(Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023; Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023). These differences underscore the clear predominance of Types I and IV in the Polish sample, contrasting with the more diverse morphological profiles seen in Jordanian and Indian populations.\u003c/p\u003e \u003cp\u003eIn the distal roots of two-rooted MTMs, differences between populations were less pronounced. Our Polish sample showed a dominant Type I configuration (94.7%), closely aligning with findings from Ahmad et al. (93.8%) and Singh et al. (96.8%)(Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016; Singh \u003cem\u003eet al.\u003c/em\u003e, 2020). This consistency supports the notion that a single canal is the typical morphology in this root across populations. Minor variations were observed in secondary configurations: Type IV emerged as the second most common in our study (2.4%), whereas Indian studies noted a higher prevalence of Type II canals (Priyank: 11.0%; Somasundaram: 9.7%)(Somasundaram, 2017; Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023). Al-Qudah et al. (2023) also reported a relatively higher Type IV frequency (8.2%). Overall, the low incidence of complex canal systems in the Polish data emphasizes the predominance of simpler morphologies in the distal roots of MTMs(Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023).\u003c/p\u003e \u003cdiv id=\"Sec18\" class=\"Section4\"\u003e \u003ch2\u003e4.1.2.1 Fusion in Two-Rooted MTMs\u003c/h2\u003e \u003cp\u003eThe present study identified 2 cases of MTMs with two fused roots, constituting 0.8% of all examined MTMs and 1% of two-rooted MTMs specifically. These findings stand in marked contrast to results published by Ahmad et al. and Al-Qudah, who reported substantially higher prevalence rates. According to these researchers, MTMs with fused roots constituted 28.6% and 9.9% of all examined third molars, respectively. Furthermore, when considering only the subset of two-rooted teeth, the prevalence of fusion reported by these authors reached 38.5% and 28.6%, respectively. This significant disparity in fusion prevalence between our study and previous research potentially indicates population-specific anatomical variations or criteria defining root fusion and show the necessity of standardizing nomenclature.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e \u003ch2\u003e4.1.3 Challenges with Root Nomenclature and Anatomical Classification\u003c/h2\u003e \u003cp\u003ePrevious research on mandibular third molar (MTM) root anatomy (Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016; Somasundaram, 2017; Waheed Sharawy and Mohamed Aly Ahmed, 2017; Singh \u003cem\u003eet al.\u003c/em\u003e, 2020; Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023) has consistently employed a directional nomenclature system utilizing the terms mesial, distal, and distolingual (M, D, DL) to identify distinct roots. However, this classification system appears problematic when evaluated against our findings. The nomenclature adopted by previous researchers suggests one of two scenarios: either all three-rooted MTMs in their studied populations present with two roots distally, or the majority of three-rooted MTMs in previously studied populations present with two roots distally, with researchers failing to distinguish cases where the third root was positioned lingually in a different location. Contrary to these classifications, our observations indicate that in three-rooted specimens, two roots are positioned in close proximity\u0026mdash;either mesially or distally\u0026mdash;with the majority exhibiting two roots on the mesial side.\u003c/p\u003e \u003cp\u003eThe naming convention utilized by Al-Qudah et al. also proves inadequate for describing the morphologies observed in our research. Their classification system identifies either a configuration of (M, D, L)\u0026mdash;where \"lingual\" implies the third root's position can be clearly recognized as lingual, similar to maxillary molars\u0026mdash;or configurations with two roots fused mesio-lingually or distally ((M, DL), D), ((D, DL), M), the first of which did not appear in our sample.\u003c/p\u003e \u003cp\u003eWe propose that this discrepancy stems from population differences. Notably, the present investigation represents the only such study conducted in Central European subjects, whereas previous research has focused on populations from India and Jordan. This anatomical reality challenges existing nomenclature and suggests the need for a revised classification system that accurately reflects the root distribution patterns observed across diverse populations.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section3\"\u003e \u003ch2\u003e4.1.4 Three-Rooted MTMs: Canal Configuration Patterns\u003c/h2\u003e \u003cp\u003eIn the studied population, we identified 31 three-rooted mandibular third molars (MTMs), with 23 specimens presenting two mesial canals. When two mesial canals were present, they invariably exhibited a Type I configuration. In cases with a single mesial root, we documented Type I (75%) and Type IV (25%) canal configurations\u0026mdash;findings that closely align with data reported from India (Priyank: Type I\u0026thinsp;=\u0026thinsp;75%; Singh: Type I\u0026thinsp;=\u0026thinsp;77.8%). Notably, other researchers have identified a broader spectrum of canal configurations (including Types II, III, and V) in the mesial root (Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016; Somasundaram, 2017; Singh \u003cem\u003eet al.\u003c/em\u003e, 2020; Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023; Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023).\u003c/p\u003e \u003cp\u003eAmong the 23 cases of three-rooted MTMs with one distal root identified in our study, the Type I configuration predominated, with only a small proportion (4%) displaying Type IV morphology. We also documented 9 cases of MTMs with two distal roots. Regarding the distobuccal (DB) root specifically, there is a consistent prevalence of Type I canals across different studies. Our findings corroborate this pattern, highlighting the relative morphological consistency of the DB root. Although Somasundaram (2017) reported Type IV configuration in all four of their identified cases, such variations remain exceptional, suggesting a generally consistent morphological pattern (Somasundaram, 2017).\u003c/p\u003e \u003cp\u003eIn the distolingual (DL) root, Type I canals similarly predominate across most reports. While our study recorded one instance of Type V, and Priyank et al. (2023) noted a single occurrence of Type II, these variations remain uncommon (Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016; Somasundaram, 2017; Waheed Sharawy and Mohamed Aly Ahmed, 2017; Singh \u003cem\u003eet al.\u003c/em\u003e, 2020; Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023; Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023)\u003c/p\u003e \u003cdiv id=\"Sec21\" class=\"Section4\"\u003e \u003ch2\u003e4.1.4.1 Fusion and Rare Variations in Three-Rooted MTMs\u003c/h2\u003e \u003cp\u003eIn addition to separate roots, three-rooted MTMs may present with fusion. Ahmad et al. (Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016) and Al-Qudah et al. (Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023) documented rare instances of three fused roots, which displayed either type VIII or a morphology that was not included in vertucci classification eg. (3\u0026thinsp;\u0026minus;\u0026thinsp;1, 3\u0026thinsp;\u0026minus;\u0026thinsp;2, 3\u0026ndash;4, 2\u0026ndash;3, 4\u0026thinsp;\u0026minus;\u0026thinsp;1, 4\u0026thinsp;\u0026minus;\u0026thinsp;2). Partial fusion, in which two roots are fused and the third remains distinct, also occurs in some populations. The most frequently observed scenario involves fusion of the mesial and disto-lingual roots, with the mesial root typically exhibiting Type IV canals and the distal root retaining a Type I pattern. There have also been two documented cases of fusion of distal and disto-lingual root. Additionally, two cases of fusion between the distal and disto-lingual roots have been documented (Al-Qudah \u003cem\u003eet al.\u003c/em\u003e, 2023). In our study we did not encounter fused three rooted MTMs.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section3\"\u003e \u003ch2\u003e4.1.5 Extremely Rare Morphologies:\u003c/h2\u003e \u003cp\u003eMandibular third molars (MTMs) with more than three roots are considered rare, and no such cases were found in the present study. A total of six MTMs with four roots were identified in the previous studies included in this comparison, all of which exhibited Type 1 canal systems. Additionally, two teeth with five roots were reported, presenting a variety of canal configurations. Remarkably there are case reports of successful treatment of such multi-rooted teeth (Plotino, 2008; Tomar \u003cem\u003eet al.\u003c/em\u003e, 2013; Garg, Mantri and Agrawal, 2014; Sinha and Sinha, 2014; Jacob \u003cem\u003eet al.\u003c/em\u003e, 2021).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003e4.1.6 Need for Standardization in Anatomical Reporting\u003c/h2\u003e \u003cp\u003eIt is worth noting that a few inconsistencies were observed in some previously published datasets, particularly in the stratification of canal types by root position. While such discrepancies do not invalidate general trends, they highlight the need for improved standardization in future anatomical research.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003e4.2 C-shaped canal\u003c/h2\u003e \u003cp\u003eThis study showed a 5.36% prevalence of C-shaped canals in the mandibular third molars, which when compared with earlier studies is more consistent with more recent studies than with earlier results. C-shaped canal was first observed by Cooke \u0026amp; Cox in 1979(Cooke and Cox, 1979). Study by Tomaszewska et al. (2018) (Tomaszewska \u003cem\u003eet al.\u003c/em\u003e, 2018) showed only 0.8% of cases in her study. Newer study by Somasundaram et al. presented a 10.3% prevalence, predominantly in single-rooted MTMs \u0026mdash;a pattern that closely matches the present study\u0026rsquo;s observation that over two-thirds of C-shaped canals occurred in single-rooted teeth. Furthermore, Priyank et al. (Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023) reported a slightly higher prevalence of C-shaped canals (7.58%) than in the current study. Present study showed a strong female predominance (92.86%) which has not been underlined in earlier studies, suggesting that future research may benefit from investigating the sex-related factors in C-shaped canal formation.\u003c/p\u003e \u003cp\u003eThese results suggest that the prevalence in the present study is higher than that reported in older data, but remains within the range of more recent observations, despite the ethnic differences between the Indian population studies conducted by Somasundaram (Somasundaram, 2017) and Priyank (Priyank \u003cem\u003eet al.\u003c/em\u003e, 2023) and the Polish population studies in the present study. Taken together, these results reflect the evolving understanding of the prevalence and complexity of C-shaped canal morphology in mandibular third molars and emphasize the importance of both sample characteristics and diagnostic methodologies in estimating the prevalence.\u003c/p\u003e \u003cp\u003eIt is relevant to mention that the term \u0026ldquo;C-shaped\u0026rdquo; was used by the aforementioned authors to describe the shape of the canal, but it can also refer to the shape of the root. For example, Al-Quedah et al. use the term \u0026ldquo;C-shaped\u0026rdquo; to define a subtype of single-rooted teeth, distinguishing it from another type they describe as \u0026ldquo;conical.\u0026rdquo; In contrast, Ahmad et al. (2016) (Ahmad \u003cem\u003eet al.\u003c/em\u003e, 2016) and Park et al. (2013) (Park \u003cem\u003eet al.\u003c/em\u003e, 2013) use the term \u0026ldquo;C-shaped root\u0026rdquo; to describe teeth regardless of the number of roots.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec25\" class=\"Section2\"\u003e \u003ch2\u003e4.3 Implications\u003c/h2\u003e \u003cp\u003eThe findings of this study have significant clinical and academic implications. In clinical settings, endodontists typically work with limited imaging capabilities\u0026mdash;usually restricted to 2D x-rays. While such imaging is of limited utility in detecting fine anatomical details of canal systems due to structural overlap, it generally permits accurate identification of root numbers. In such cases, the results of the present study provide valuable guidance, enabling clinicians to make informed predictions about potential canal configurations based on root number, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The documented frequency distributions of root morphologies and canal configurations serve as a particularly valuable reference for anticipating the number and location of canal orifices. This knowledge can enhance procedural efficiency and reduce the risk of missed canals. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e illustrates the frequency of different numbers of canal orifices based on root number and their location.\u003c/p\u003e \u003cp\u003eBeyond its direct medical uses, this research helps us better understand MTMs anatomy by adding to our knowledge of how MTM can vary in shape, showing important differences between populations when compared to past studies from other regions and emphasizing the need for thorough training in handling C-shaped canals since they are fairly common (5.36%) in our population.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec26\" class=\"Section2\"\u003e \u003ch2\u003e4.4 Study limitations and future directions\u003c/h2\u003e \u003cp\u003eAmong the limitations of our study, we must state that the sample size was limited, and the study population was chosen exclusively from the Lower Silesia region, which may not be a representative for broader populations. We could not use the small field of view CBCT images (5 \u0026times; 5 cm) due to the limited number of cases, although they might have provided additional information about root canal anatomy. A small field of view is generally used by endodontists, but in our facility, full CBCT scans\u0026mdash;or maxillary or mandibular CBCT scans\u0026mdash;remain the most commonly performed. Regional genetic, and environmental factors could influence MTM morphology, hence limiting the generalizability of the findings to other populations. Given the single-region sample and specific demographic characteristics of the study group, the applicability of our results to broader populations or different clinical contexts should therefore be considered with caution. Although this study utilized CBCT for accurate assessment of root and canal morphology, its application in clinical practice is limited. Endodontists often depend on conventional periapical radiographs, which do not provide the same level of detail as CBCT scans. Consequently, translating the detailed anatomical findings from this study to routine endodontic practice may be challenging, as clinicians must infer 3D structures from 2D images. This discrepancy may affect the precision and the result of endodontic.\u003c/p\u003e \u003cp\u003eA significant limitation affecting this and other anatomical studies is the absence of a standardization on the terminology and classification of root and canal anatomy. Variations in defining terms such as \u0026ldquo;separate roots\u0026rdquo;, \"root bifurcation\", and \u0026ldquo;root fusion\u0026rdquo; can make the direct comparisons between studies difficult. Since the study relied on the availability of CBCT scans, the sample may be biased toward individuals requiring imaging for clinical purposes (e.g., orthodontic treatment or oral surgery, or endodontic treatment). This may accidentally exclude individuals with no clinical need for CBCT imaging, thereby decreasing the representativeness of the sample.\u003c/p\u003e \u003cp\u003eAI (artificial intelligence) usage to segment CBCT scans is a promising research direction. Traditional methods are time-consuming, and AI, especially deep learning models, can significantly improve the speed and accuracy of segmentation. This automation will streamline scan processing, enable analysis of larger samples, and improve the repeatability of studies by reducing observer bias. It is necessary to attempt to employ more heterogenous samples from different geographic regions to ensure that the results can be generalized to broader populations. The lack of a unified terminology and classification of root and canal anatomy remains a challenge. Future research should prioritize developing consistent definitions of terms such as \u0026ldquo;separate roots,\u0026rdquo; \u0026ldquo;root bifurcation,\u0026rdquo; and \u0026ldquo;root fusion\u0026rdquo; to facilitate direct comparisons between studies and to promote meta-analysis. We have to underline that CBCT is a practical compromise between resolution and accessibility, further studies could investigate the use of higher resolution imaging technologies such as micro-CT, which cannot be used in vivo, to more accurately visualize and classify complex root canal morphologies. Such imaging may provide a more advanced understanding of root canal systems. Further research is needed to reduce the differences between the details that can be detected in CBCT examinations when compared with standard X-ray images.\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThis CBCT-based study provides new insight into the complex root and canal morphology of mandibular third molars (MTMs) in a Central European population. Two-rooted configurations were most common, regardless of sex, with clear differences in root morphology observed between sexes. Vertucci\u0026rsquo;s Type I canal system predominated across all root types, while C-shaped canals\u0026mdash;though relatively uncommon\u0026mdash;were significantly more frequent in female subjects and single-rooted MTMs.\u003c/p\u003e \u003cp\u003eThese findings have important clinical implications. They can assist endodontists in anticipating root canal anatomy based on root number and patient demographics, especially when CBCT is unavailable and clinicians must rely on 2D radiographs. The study also highlights the anatomical variability among populations and the need for tailored diagnostic approaches.\u003c/p\u003e \u003cp\u003eFuture research should aim to improve population diversity in anatomical studies, adopt consistent terminology, and explore the integration of AI-assisted CBCT analysis to enhance accuracy, efficiency, and reproducibility in root canal morphology assessment.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflicts of interest related to this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was funded by Wrocław Medical University as part of the co-financing provided under the subsidy for maintaining and developing research potential in 2022 (SUBZ.B010.22.040). The funding source had no involvement in the study\u0026apos;s design, data collection or analysis, decision to publish, or manuscript preparation. No additional external funding was received for this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval statement and document\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe hereby confirm that our work fully complies with the ethical requirements and policies specified by the journal. All research has been conducted in accordance with recognized ethical standards, and no part of the study violates the principles of integrity, transparency, or responsible authorship. All authors have contributed to the work, approved the final version of the manuscript, and agree with its submission.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of generative AI and AI-assisted technologies in the writing process.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the preparation of this work the author(s) used OpenAi chatGPT in order to improve the readability and language of the manuscript and as an assisting tool during extraction and parsing of tabular data from other sources. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available in Supplementary files under Supplement 5.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCredit authorship contribution statement \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnna Olczyk: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing \u0026ndash; original draft, Validation, Writing -review \u0026amp; editing, Project administration\u003c/p\u003e\n\u003cp\u003eBarbara Malicka: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing \u0026ndash; original draft, Validation, Writing -review \u0026amp; editing, Project administration\u003c/p\u003e\n\u003cp\u003ePaweł Stenzel: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing \u0026ndash; original draft, Validation, Writing -review \u0026amp; editing, Project administration\u003c/p\u003e\n\u003cp\u003eUrszula Sękowska: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing \u0026ndash; original draft, Validation, Writing -review \u0026amp; editing, Project administration\u003c/p\u003e\n\u003cp\u003eKatarzyna Skośkiewicz - Malinowska: Conceptualization, Methodology, Data curation, Formal analysis, Investigation, Writing \u0026ndash; original draft, Validation, Writing -review \u0026amp; editing, Project administration, Funding acquisition.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eWe sincerely thank Krzysztof Kujawa, Ph.D., DSc, Head of the Statistical Analysis Center at Wroclaw Medical University, for his invaluable guidance and dedicated support during this research. His exceptional expertise and insightful advice were instrumental in elevating the quality of our study.\u003c/em\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAhmad, I., Azzeh, M., Zwiri, AbdalwahabM.A., Abu Haija, M.A., Diab, M., 2016. Root and root canal morphology of third molars in a Jordanian subpopulation. Saudi Endodontic Journal 6, 113. https://doi.org/10.4103/1658-5984.189350\u003c/li\u003e\n\u003cli\u003eAhmed, H.M.A., 2022. A critical analysis of laboratory and clinical research methods to study root and canal anatomy. Int Endod J 55, 229\u0026ndash;280. https://doi.org/10.1111/iej.13702\u003c/li\u003e\n\u003cli\u003eAhmed, H.M.A., Che Ab Aziz, Z.A., Azami, N.H., Farook, M.S., Khan, A.A., Mohd Noor, N.S., Ayoub, A.A., Imran, Z.A., Halim, M.S., Pai, A.R. V., Kacharaju, K.R., Mohammad, N., Nagendrababu, V., Nabhan, M.S., Dummer, P.M.H., 2020. 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Sci Rep 13, 6901. https://doi.org/10.1038/s41598-023-34134-7\u003c/li\u003e\n\u003cli\u003eCooke, H.G., Cox, F.L., 1979. C-shaped canal configurations in mandibular molars. The Journal of the American Dental Association 99, 836\u0026ndash;839. https://doi.org/10.14219/jada.archive.1979.0402\u003c/li\u003e\n\u003cli\u003eDe Bruyn, L., Vranckx, M., Jacobs, R., Politis, C., 2020. A retrospective cohort study on reasons to retain third molars. Int J Oral Maxillofac Surg 49, 816\u0026ndash;821. https://doi.org/10.1016/j.ijom.2019.10.003\u003c/li\u003e\n\u003cli\u003eDrăgan, O.C., Fărcăşanu, A.Ş., C\u0026acirc;mpian, R.S., Turcu, R.V.F., 2016. Human tooth and root canal morphology reconstruction using magnetic resonance imaging. Clujul Medical 89, 137\u0026ndash;142. https://doi.org/10.15386/cjmed-555\u003c/li\u003e\n\u003cli\u003eGarg, A.K., Mantri, V.R., Agrawal, N., 2014. Endodontic Management of Mesiobuccal-2 Canal in Four-Rooted and Five-Canalled Mandibular Third Molar. J Contemp Dent Pract 15, 363\u0026ndash;366. https://doi.org/10.5005/jp-journals-10024-1544\u003c/li\u003e\n\u003cli\u003eGulabivala, K., Aung, T.H., Alavi, A., Ng, Y., 2001. Root and canal morphology of Burmese mandibular molars. Int Endod J 34, 359\u0026ndash;370. https://doi.org/10.1046/j.1365-2591.2001.00399.x\u003c/li\u003e\n\u003cli\u003eGulabivala, K., Ng, Y.L., 2023. Factors that affect the outcomes of root canal treatment and retreatment\u0026mdash;A reframing of the principles. Int Endod J 56, 82\u0026ndash;115. https://doi.org/10.1111/iej.13897\u003c/li\u003e\n\u003cli\u003eGulabivala, K., Opasanon, A., Ng, Y. ‐L., Alavi, A., 2002. Root and canal morphology of Thai mandibular molars. Int Endod J 35, 56\u0026ndash;62. https://doi.org/10.1046/j.1365-2591.2002.00452.x\u003c/li\u003e\n\u003cli\u003eHafezi, L., Sakhdari, S., Moaiyedmohseni, N., 2019. 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J Endod 36, 1547\u0026ndash;1551. https://doi.org/10.1016/j.joen.2010.05.008\u003c/li\u003e\n\u003cli\u003ePark, J.B., Kim, N.R., Park, S., Ko, Y., 2013. Evaluation of number of roots and root anatomy of permanent mandibular third molars in a Korean population, using cone-beam computed tomography. Eur J Dent 7, 296\u0026ndash;301. https://doi.org/10.4103/1305-7456.115413\u003c/li\u003e\n\u003cli\u003ePlotino, G., 2008. A Mandibular Third Molar with Three Mesial Roots: A Case Report. J Endod 34, 224\u0026ndash;226. https://doi.org/10.1016/j.joen.2007.11.014\u003c/li\u003e\n\u003cli\u003ePriyank, H., Viswanath, B., Sriwastwa, A., Hegde, P., Abdul, N.S., Golgeri, M.S., C, S.G., Mathur, H., 2023. Radiographical Evaluation of Morphological Alterations of Mandibular Third Molars: A Cone Beam Computed Tomography (CBCT) Study. Cureus. https://doi.org/10.7759/cureus.34114\u003c/li\u003e\n\u003cli\u003eSERT, S., BAYIRLI, G., 2004. 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Clinical Anatomy 31, 797\u0026ndash;811. https://doi.org/10.1002/ca.23080\u003c/li\u003e\n\u003cli\u003eTomaszewski, K.A., Henry, B.M., Ramakrishnan, P.K., Roy, J., Vikse, J., Loukas, M., Tubbs, R.S., Walocha, J.A., 2017. Development of the Anatomical Quality Assurance (AQUA) checklist: Guidelines for reporting original anatomical studies. Clinical Anatomy. https://doi.org/10.1002/ca.22800\u003c/li\u003e\n\u003cli\u003eVertucci, F., Seelig, A., Gillis, R., 1974. Root canal morphology of the human maxillary second premolar. Oral Surgery, Oral Medicine, Oral Pathology 38, 456\u0026ndash;464. https://doi.org/10.1016/0030-4220(74)90374-0\u003c/li\u003e\n\u003cli\u003evon Elm, E., Altman, D.G., Egger, M., Pocock, S.J., G\u0026oslash;tzsche, P.C., Vandenbroucke, J.P., 2008. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. J Clin Epidemiol 61, 344\u0026ndash;349. https://doi.org/10.1016/j.jclinepi.2007.11.008\u003c/li\u003e\n\u003cli\u003eWaheed Sharawy, W., Mohamed Aly Ahmed, H., 2017. Case Report Endodontic Management of a Three Rooted Mandibular Third Molar with a Dilacerated Distal Root and Close Approximation to the Inferior Alveolar Canal: A Case Report 7. https://doi.org/10.5577/intdentres\u003c/li\u003e\n\u003cli\u003eWeine, F.S., Healey, H.J., Gerstein, H., Evanson, L., 1969. Canal configuration in the mesiobuccal root of the maxillary first molar and its endodontic significance. Oral Surgery, Oral Medicine, Oral Pathology 28, 419\u0026ndash;425. https://doi.org/10.1016/0030-4220(69)90237-0\u003c/li\u003e\n\u003cli\u003eYang, L., Han, J., Wang, Q., Wang, Z., Yu, X., Du, Y., 2022. Variations of root and canal morphology of mandibular second molars in Chinese individuals: a cone-beam computed tomography study. BMC Oral Health 22, 274. https://doi.org/10.1186/s12903-022-02299-8\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Mandibular third molars, CBCT, root canal morphology, C-shaped canals, Vertucci classification, dental anatomy, root canal configuration, sex differences","lastPublishedDoi":"10.21203/rs.3.rs-8282672/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8282672/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eUnderstanding the root and canal morphology of mandibular third molars (MTMs) is crucial for anatomical characterization of human dentition and effective endodontic treatment. This study investigates the number of roots, canal configurations, and the prevalence of C-shaped canals in MTMs using Cone Beam Computed Tomography (CBCT).\u003c/p\u003e\u003ch2\u003eObjectives\u003c/h2\u003e \u003cp\u003eTo analyse root count, sex-related differences, canal configurations, and the prevalence of C-shaped canals in MTMs.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis cross-sectional study analysed CBCT scans of 261 MTMs from patients aged 18 and over according to Vertucci\u0026rsquo;s classification. Data were collected at the X-Ray Diagnostic Laboratory of (city name anonymized due to double blind policy) Medical University from January to April 2022. Interobserver agreement was excellent (κ\u0026thinsp;=\u0026thinsp;0.917). Statistical analyses included chi-squared tests with Bonferroni correction (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Effect size was assessed using Cohen\u0026rsquo;s \u0026ldquo;w\u0026rdquo; (0.0172) with test power of 0.64 at an alpha level of 0.05.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eMost MTMs had two roots (79.69%), followed by three roots (11.81%) and a single root (8.43%). Two-rooted teeth were more frequent in males (87.27%) than in females (74.17%, p\u0026thinsp;=\u0026thinsp;0.027). Type I was the predominant root canal configuration in all categories. C-shaped canals were present in 5.36% of teeth, predominantly in single-rooted teeth (71.43%) and females (92.86%).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eThis study highlights variations in anatomical diversity of MTMs, emphasizing clinical importance of CBCT for accurate diagnosis and treatment planning, expanding anatomical knowledge. Findings underscore the prevalence of C-shaped canals and sex-related differences in root structure.\u003c/p\u003e","manuscriptTitle":"Morphology of Third Mandibular Molars – An In Vivo Cone Beam Computed Tomography Study in Lower Silesia","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-09 12:21:28","doi":"10.21203/rs.3.rs-8282672/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-25T07:20:04+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-21T15:12:21+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-17T07:55:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"251209487120623262587206611065201190965","date":"2026-02-15T18:49:59+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-13T23:17:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"303745071161186894377385545753345684972","date":"2026-02-10T13:00:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"160578914775431174460890357092829488329","date":"2026-02-10T10:08:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"174106154730530084564882279264465255190","date":"2026-02-04T11:26:26+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-04T10:01:52+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-12-15T17:17:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-12T05:43:47+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-12T05:41:58+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-12-04T21:22:06+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9a1f5af2-681f-446c-b75f-af435b7a3b8e","owner":[],"postedDate":"February 9th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-08T08:53:37+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-09 12:21:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8282672","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8282672","identity":"rs-8282672","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}