CBCT assessment of lingual cortical plate morphology and pre-existing perforation in impacted mandibular third molars

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However, detailed information on coronal and apical lingual cortical thickness and the factors influencing pre-existing lingual cortex perforation remains limited. Methods This retrospective cross-sectional study evaluated cone-beam computed tomography (CBCT) scans of 201 patients with impacted mandibular third molars. Lingual cortical thickness was measured at coronal and apical levels, and pre-existing perforation was recorded. Age, sex, side, angulation (Winter classification), impaction depth (Pell and Gregory classification), and root morphology were analyzed. Non-parametric tests were used for group comparisons, and binary logistic regression was performed to identify independent predictors of perforation. Results Mean lingual cortical thickness was 2.04 ± 1.12 mm at the coronal level and 0.86 ± 0.80 mm at the apical level, with an overall mean of 1.45 ± 0.70 mm. Pre-existing perforation was detected in 1.5% of cases. Apical (p = 0.02) and overall thickness (p = 0.01) were significantly lower in the perforation group. Angulation type significantly affected coronal (p = 0.046) and overall thickness (p = 0.028), and impaction depth was associated with coronal thickness (p = 0.041). Sex, side, and root morphology showed no significant associations. Age was the only independent predictor of lingual cortex perforation (OR = 1.306; 95% CI: 1.088–1.568; p = 0.004). Conclusions The lingual cortical plate adjacent to impacted mandibular third molars is frequently thin, particularly at the apical level, whereas pre-existing perforation is rare. Thinner cortex and increasing age significantly increase the risk of lingual cortical perforation. Detailed preoperative CBCT evaluation is essential for safer surgical planning. Impacted mandibular third molar Lingual cortical plate Cone-beam computed tomography Lingual cortex perforation Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Impacted mandibular third molars are among the most common conditions encountered in oral and maxillofacial surgery and are associated with a wide variety of local complications, including pericoronitis, distal cervical caries of the second molar, root resorption, periodontal defects, cysts, and tumors [ 1 – 4 ]. More serious but less common sequelae include mandibular fractures affecting the inferior alveolar and lingual nerves and neurosensory disorders [ 5 – 7 ]. The lingual cortical plate adjacent to the mandibular third molar tooth plays a critical protective role for the lingual nerve and submandibular spaces. Excessive force or incorrect elevation during third molar surgery can cause fracture of the lingual plate or displacement of root fragments beyond the cortex, potentially leading to lingual nerve injury and difficult surgical recovery [ 8 – 10 ]. Recent cone-beam computed tomography (CBCT) studies have emphasized that pre-existing discontinuities of the lingual cortex may be present prior to surgery, suggesting that some postoperative cortical “defects” represent anatomical variations rather than iatrogenic injury [ 11 , 12 ]. CBCT has become the preferred three-dimensional imaging method for evaluating impacted mandibular third molars because it provides three-dimensional information about root morphology, the mandibular canal, and the bucco-lingual dimensions of the bone surrounding this canal [ 13 , 14 ]. Several CBCT-based studies have focused specifically on the lingual plate in the third molar region. Wang et al. classified the topographic relationship between the root apex and the lingual plate of mesial and horizontal impacted mandibular third molars as non-contact, contact, and perforation, and identified impacted depth and lingual plate morphology as important risk factors for root-cortex contact or perforation [ 15 ]. Amin et al. reported a relatively high incidence of pre-existing lingual cortex perforation in their study and emphasized the importance of recognizing such defects on CBCT prior to surgery [ 11 ]. Multiple CBCT studies have demonstrated that the lingual cortical thickness surrounding impacted mandibular third molars is frequently < 1 mm, particularly in the apical region. Previous investigations reported that both coronal and apical cortical thickness values generally remain below 1 mm, and that thinner plates are associated with higher rates of crown and root perforation. Moreover, lingual plate thickness and density have been shown to vary significantly depending on impaction angulation, depth, and root number, and a negative correlation between bucco-lingual tooth position and lingual cortical thickness has also been reported [ 16 – 19 ]. Despite this growing body of evidence, several important questions remain unanswered. First, while many studies have emphasized the distances between the tooth and the lingual plate or categorical root-cortex relationships, fewer studies have separately presented detailed measurements of lingual cortical thickness at the coronal and apical levels around impacted mandibular third molars [ 16 , 17 ]. Second, existing data on the effect of patient-related factors such as age and sex on lingual cortical thinning and perforation are inconsistent; some authors found no effect of age, while others suggested potential age-related changes in cortical morphology [ 11 , 20 ]. Given these limitations, the aim of this study is to analyze the relationship between the existing CBCT study, (i) by measuring the lingual cortical bone thickness at the coronal and apical levels, (ii) to determine the prevalence of pre-existing lingual cortex perforation, and (iii) to analyze the relationship between lingual cortical thickness and perforation with age, sex, side, impaction type (Winter classification), depth (Pell and Gregory classification), and root morphology. The authors hypothesized that the apical lingual cortex would be thinner than the coronal cortex, that pre-existing perforation would be associated with reduced cortical thickness, and that age and impaction characteristics would significantly affect lingual cortical morphology. Materials And Methods This retrospective cross-sectional study was conducted using CBCT scans obtained for the diagnostic evaluation of impacted mandibular third molars. The study was conducted in accordance with medical protocols and the principles of the Declaration of Helsinki. Ethical approval for the study was obtained from the Clinical Research Ethics Committee of Van Yuzuncu Yil University (approval no. 2025/05–13, May 16, 2025) and was conducted between May 2025 and October 2025 at the Oral and Maxillofacial Surgery and Dental and Maxillofacial Radiology clinics of Van Yuzuncu Yil University. A post-hoc power analysis for the logistic regression model assessing the risk of perforation development was performed using G*Power 3.1 software. The Wald test z-statistic z = 2.88 for the age variable found to be significant in the model, the total sample size N = 201, and the significance level α = 0.05 were included in the analysis. The calculated effect size based on these values was Odds Ratio = 1.306 (β = 0.267), and according to the G*Power output, the post-hoc power of the model was found to be in the range of 85–88%. This result indicates that the logistic regression model predicting the risk of perforation based on the age variable has a high level of statistical power. A total of 201 patients with an impacted third mandibular tooth were included in the study. Patients ranged in age from 14 to 53 years, with a mean age of 21.10 ± 6.97 years. Inclusion criteria: The presence of an impacted mandibular third molar tooth requiring CBCT imaging; the availability of high-quality CBCT images in which the entire lingual cortical plate, the crown portion of the tooth, and the root apex are clearly visible; the absence of metallic artifacts or motion artifacts affecting the posterior mandible; and the analysis of only one tooth per patient to prevent clustering. Exclusion criteria: Patients with a history of mandibular surgery, trauma, fracture, cyst, tumor, osteolytic lesions, or developmental anomalies; systemic diseases known to affect bone density or quality (e.g., osteoporosis, metabolic bone disease); CBCT scans containing artifacts or where the lingual plate cannot be fully visualized, and impacted or partially impacted third molars. The KaVo 3D eXam (Biberach, Germany) tomography device was used for CBCT measurements. Individuals are seated during CBCT scans. The device self-calibrates before each image acquisition. Additionally, to standardize CBCT images, the Frankfurt plane is parallel to the horizontal plane, and the teeth are in centric occlusion and maximum intercuspation. Furthermore, to restrict patient movement, we use a special mandibular chin strap and cephalostats to stabilize the head. All tomography procedures were performed at 120 kVp, 5 mAs, 7 s scan time, 0.125-0.4 mm voxel size, and l30 mm FOV. This modification applies to all CBCT images, including coronal, sagittal, and axial images. CBCT images of axial and sagittal sections converted to Digital Imaging and Communications in Medicine (DICOM) formats were examined. A voxel size of 0.4 mm was used in this study. Lingual bone thickness calculations were performed using the eXam Vision program (Biberach, Germany). The radiometric evaluations within the scope of the study were performed on cross-sectional images obtained from CBCT scans. Prior to analysis, the images were reoriented according to standard anatomical planes in the multiplanar reconstruction (MPR) mode and aligned with the long axis of the tooth as a reference. To determine the anatomical relationship between the lingual cortical bone and the impacted mandibular third molar teeth, sections passing through the cementoenamel junction and root apex of the tooth were examined. At these determined levels, the shortest distance between the lingual surface of the tooth and the inner surface of the lingual cortical bone was measured in millimeters. In addition to quantitative measurements, the integrity of the lingual cortex was assessed, and any discontinuity or loss of integrity at the cortical bone margins was recorded as the presence of “perforation.” Interobserver reliability for linear measurements was assessed using the two-way random-effects model with absolute agreement [ICC (2,1)]. For CEJ measurements obtained by the two observers, the intraclass correlation coefficient was ICC = 0.936, whereas for apical measurements the ICC was 0.963, indicating excellent interobserver agreement for both parameters. For the categorical assessment of lingual cortical perforation (present/absent), interobserver reliability was evaluated using Cohen’s kappa coefficient. The two observers provided identical ratings for all 20 cases (2 “present”, 18 “absent”), yielding a kappa value of κ = 1.00, which reflects perfect agreement. All impacted mandibular third molars were classified according to their angulation, depth of impaction and root morphology based on CBCT images. Tooth angulation was determined using Winter’s classification (Fig. 1 ) and categorised as mesioangular, vertical, horizontal or distoangular according to the long axis of the third molar relative to the second molar. The depth of impaction was assessed using the Pell and Gregory classification (Fig. 2 – 3 ), based on the relationship of the occlusal surface of the third molar to the occlusal plane of the second molar, and teeth were classified as Class A, Class B or Class C. In addition, root morphology (Fig. 4 ) was evaluated on CBCT images and categorised as single root, fused roots, or separated multiple roots. All classifications were performed on multiplanar reconstructed CBCT sections by an experienced oral and maxillofacial radiologist under standardised viewing conditions. Statistical Analyses All statistical analyses were performed using IBM SPSS Statistics (Version 25). The normality of the continuous variables was assessed with the Shapiro–Wilk test, and since the data did not show a normal distribution pattern, non-parametric statistical methods were employed. Descriptive statistics were presented as mean ± standard deviation (SD), minimum, and maximum values. Comparisons of lingual cortical bone thickness between two independent groups (sex and side) were conducted using the Mann–Whitney U test. The relationship between the presence of lingual cortical perforation and bone thickness at coronal, apical, and overall levels was also evaluated using the Mann–Whitney U test. Comparisons involving more than two groups (age decades, Winter’s angulation types, Pell & Gregory depth classification, and root morphology) were analyzed using the Kruskal–Wallis test, and significant findings were further interpreted through mean rank distributions. To identify predictors of lingual cortical perforation, a binary logistic regression analysis was performed. Age, sex, root morphology, Winter’s classification, and Pell & Gregory depth were included as independent variables in the model. The level of statistical significance was set at p < 0.05. Results A total of 201 CBCT scans of impacted mandibular third molars were evaluated in this study. The mean age of the participants was 21.10 ± 6.97 years (range: 14–53 years). The mean lingual cortical bone thickness was 2.04 ± 1.12 mm at the coronal level and 0.86 ± 0.80 mm at the apical level. The overall mean lingual bone thickness, calculated from these measurements, was 1.45 ± 0.70 mm (range: 0.24–3.72 mm). The mean number of roots per tooth was 1.84 ± 0.37 (Table 1 ). Table 1 Descriptive statistics of demographic data and lingual cortical bone thickness measurements Variables N Mean ± SD Min – Max Age (Years) 201 21.10 ± 6.97 14– 53 Coronal Lingual Bone Thickness (mm) 201 2.04 ± 1.12 0– 5.39 Apical Lingual Bone Thickness (mm) 201 0.86 ± 0.80 0–4.97 Overall Mean Bone Thickness (mm) 201 1.45 ± 0.70 0.24–3.72 Number of Roots 201 1.84 ± 0.37 1– 2 N: Sample Size, SD:Standard Deviation, Min: Minimum, Max:Maximum. Comparison according to sex and impaction side The Mann–Whitney U test revealed no significant association between sex and lingual cortical bone thickness. Coronal (Z = − 1.298; p = 0.19), apical (Z = − 0.237; p = 0.81), and overall mean thickness values (Z = − 0.967; p = 0.33) did not differ significantly between females and males. Similarly, impaction side (right/left) did not significantly influence coronal (Z = − 0.045; p = 0.96), apical (Z = − 0.955; p = 0.34), or overall thickness (Z = − 0.443; p = 0.66) values, indicating bilateral symmetry (Table 2 ). Table 2 Comparison of lingual cortical bone thickness according to sex and side Variables Groups N Coronal MR P* Apical MR P* Overall MR P* Sex Female 124 96.80 0.19 101.77 0.81 97.88 0.33 Male 77 107.76 99.77 106.03 Side Right 102 101.18 0.96 104.86 0.34 102.79 0.66 Left 99 100.81 97.03 99.16 Perforation Status Present 3 39 0.06 24.5 0.02 19.17 0.01 Absent 198 101.94 102.16 102.24 N: Sample Size, MR: Mean Rank, *Mann-Whitney U Test, p < 0.05. Comparison according to lingual cortex perforation A significant difference was found between individuals with and without lingual cortex perforation. Apical lingual bone thickness (Z = − 2.295; p = 0.02) and overall mean thickness (Z = − 2.455; p = 0.01) were significantly lower in the perforation group. However, coronal thickness did not differ significantly between groups (Z = − 1.860; p = 0.063) (Table 2 ). Comparison among age groups The Kruskal–Wallis test demonstrated a significant difference in apical thickness among age groups (χ² = 11.053; p = 0.026). Although coronal bone thickness did not reach statistical significance (χ² = 9.383; p = 0.052), the p-value approached the significance threshold and the mean rank of the oldest group (Group 5: 28.20) was notably lower, suggesting a potential decline in coronal bone support with age. No significant differences were found for overall mean bone thickness among age groups (p = 0.403) (Table 3). Comparison according to angulation type Angulation type significantly affected coronal lingual bone thickness (χ² = 7.999; p = 0.05) and overall mean thickness (χ² = 9.066; p = 0.03). The highest coronal values were observed in mesioangular impactions (Mean Rank: 106.13), while the highest overall mean values occurred in horizontal impactions (Mean Rank: 123.71). Vertical and distoangular impactions showed lower mean ranks, indicating reduced lingual bone support. No significant difference was detected in apical thickness among angulation types (p = 0.314) (Table 3). Comparison according to Pell & Gregory depth classification A significant association was found between impaction depth and coronal bone thickness (χ² = 6.403; p = 0.41). Level B showed the greatest coronal thickness (Mean Rank: 113.88), whereas Level C demonstrated the lowest (Mean Rank: 91.95). No significant differences were detected for apical (p = 0.224) or overall mean thickness (p = 0.213) values among the depth groups (Table 3). Comparison according to root morphology Root morphology (single root, fused roots, separated roots) did not significantly affect lingual cortical bone thickness. No significant differences were detected in coronal (χ² = 3.755; p = 0.153), apical (χ² = 2.155; p = 0.340), or overall thickness (χ² = 2.034; p = 0.362) values (Table 3). Predictors of lingual cortex perforation Logistic regression analysis identified age as a significant predictor of lingual cortex perforation (p = 0.004). Each one-year increase in age raised the perforation risk by 1.306 times (Odds Ratio: 1.306; 95% CI: 1.088–1.568). Sex was not a significant predictor (p = 0.927). Table-3: Evaluation of lingual cortical bone thickness according to age groups, Winter’s classification, Pell & Gregory depth classification, and root morphology Variables Groups N Coronal MR P* Apical MR P* Overall MR P* Age Group 1.Dekad 123 103.74 0.05 107.67 0.03 105.51 0.4 2.Dekad 62 104.53 89.73 97.98 3.Dekad 8 80.88 104.06 89.50 4.Dekad 3 90.83 16.17 65.50 5.Dekad 5 28.2 122.80 67.20 Winter’s Classification Mesioangular 155 106.13 46 102.17 314 104.31 28 Vertical 27 76.00 85.39 75.93 Horizontal 14 104.68 120.07 123.71 Distoangular 5 66.60 95.60 70.10 Pell & Gregory Depth Class A 19 97.66 41 84.53 224 89.32 213 Class B 78 113.88 97.03 109.68 Class C 104 91.95 106.99 96.63 Root Morphology Single 24 83.54 153 117.35 340 95.90 362 Fused 21 116.95 98.86 117.79 Separate 156 101.54 98.77 99.53 N: Sample Size, MR: Mean Rank, *Kruskal Wallis Test, p<0.05. Discussion This CBCT-based study evaluated the lingual cortical plate adjacent to impacted mandibular third molars in a sample of 201 patients and demonstrated that the lingual cortex is frequently thin, particularly at the apical level, whereas pre-existing perforation is uncommon. The mean coronal and apical lingual cortical thickness values obtained in this study (2.04 mm and 0.86 mm, respectively) are consistent with the results of previous CBCT studies reporting that the lingual plate gradually thins toward the root apex. Studies have reported that apical lingual cortical thickness falls below 1 mm in most cases and have emphasized that this region is structurally weak [ 16 , 17 , 21 ]. Wang et al. and Gumber et al. have indicated that this apical thinning causes the lingual plate to become more susceptible to fracture during tooth elevation and surgical manipulations [ 15 , 18 ]. The significant thinning of the apical cortex observed in our study once again highlights the clinical importance of preoperative CBCT evaluation, particularly in cases of deep impaction. In this study, preoperative lingual cortical perforation was detected in only 1.5% of cases, which is significantly lower than the perforation rates reported in other studies [ 11 , 17 ]. This difference may be due to differences in the population characteristics of the studies, the presence of impacted teeth in the sample, and the radiological criteria used to define perforation. However, the finding of significantly lower apical and overall cortical thickness in cases with perforation is consistent with previous studies showing that perforation is associated with severe cortical thinning and concavity [ 18 , 20 ]. It has been demonstrated that lingual cortical morphology can vary depending on the characteristics of impaction. Several CBCT studies have reported that horizontal and mesioangular impactions are more frequently associated with thin lingual plate or direct root–cortical contact due to the root apex being positioned closer to the lingual cortical surface [ 15 , 19 ]. Dumanlı et al. also reported the highest perforation rates in horizontal impactions [ 17 ]. Although the Winter classification and Pell & Gregory depth classification did not emerge as independent predictors of perforation in the logistic regression analysis in the present study, they showed significant correlations with lingual cortical thickness in univariate analyses. This suggests that the impaction position affects lingual bone morphology, but this effect may be overshadowed by stronger predictors such as age. One of the most important findings of this study is that age was identified as the sole independent predictor for lingual cortical perforation. Age-related changes in mandibular cortical morphology have been discussed in various radiological and morphological studies. Zhao et al. demonstrated that lingual bone thickness and morphology can vary with age and skeletal pattern. Halder et al. reported age-related changes in bone density and thickness in the lingual plate region [ 20 , 22 ]. In contrast, Amin et al. did not find a significant relationship between age and perforation [ 11 ]. First and foremost, the demographic profile of our study population was predominantly young (mean age: 21.10 ± 6.97 years). Since our multivariate analysis identified age as a significant predictor of perforation, it is plausible that the lower incidence is a direct reflection of the younger cohort, whereas studies including older populations would naturally exhibit higher perforation rates due to age-related bone remodeling. Second, ethnic variations in skeletal structure and bone density may play a role; our sample consisted of a specific ethnic group in Eastern Anatolia, which may differ from the populations analyzed in other studies. Finally, the voxel size used in CBCT imaging is a critical technical factor. We utilized a voxel size of 0.4 mm, which is standard for clinical assessment; however, studies utilizing higher resolution protocols (smaller voxel sizes) might be more sensitive in detecting micro-perforations that are not visible at 0.4 mm, potentially explaining the higher rates reported elsewhere. Sex, side, and root morphology did not show a significant relationship with lingual cortical thickness or perforation. These results are consistent with findings from previous CBCT studies indicating that these variables are not as determinative of lingual cortical morphology as impaction depth, tooth angulation, and individual cortical anatomical structure [ 16 , 18 , 21 ]. Recent studies have examined the relationship between third molar impaction and mandibular morphology, demonstrating significant correlations between the retromolar space, mandibular skeletal shape, and the likelihood of impaction [ 23 , 24 ]. Although these studies did not directly measure lingual cortical thickness, they complement the findings of the present study by emphasizing the effect of mandibular anatomical structure on impaction and surgical difficulty. This study, however, focuses on the lingual cortical plate, a critical region directly related to surgical complications, thereby providing a unique and clinically significant contribution to the literature. From a clinical perspective, the fact that the apical lingual cortex is often less than 1 mm thick indicates the need for careful manipulation during elevation and the necessity to avoid excessive lingual force, particularly in elderly patients and those with deep impaction. Even in the absence of perforation, an excessively thin cortex may increase the risk of lingual plate fracture or displacement of root fragments into the submandibular or sublingual spaces. Such complications have also been reported in previous surgical complication studies [ 8 , 9 ]. Therefore, detailed preoperative CBCT evaluation to identify high-risk anatomical configurations is strongly recommended for safer surgical planning. The methodological strengths of this study include a relatively large sample size, standardized two-level (coronal and apical) lingual cortical thickness measurements, and the use of multivariate logistic regression analysis to identify independent predictors of perforation. Additionally, the inclusion of parameters closely related to surgical difficulty, such as Winter impaction classification, Pell & Gregory depth and ramus relationship classifications, and root morphology, in the same analysis model has enabled a more comprehensive assessment of anatomical factors that may influence lingual cortical morphology. The study also has some limitations. The retrospective design does not allow for complete control over patient selection, and CBCT images were obtained for clinical indications rather than for research purposes. Furthermore, since lingual cortical integrity was not confirmed intraoperatively, it was not possible to directly correlate radiological findings with actual surgical complications. Another critical limitation concerns the statistical power regarding the analysis of predictors for perforation. Since the prevalence of pre-existing perforation was quite low in our sample (1.5%, n = 3), the logistic regression results identifying age as a predictor should be interpreted with caution due to the limited number of events. Moreover, our study population consisted predominantly of young adults (mean age: 21.10 ± 6.97 years), with fewer participants in advanced age groups. In addition, the fact that the study was conducted in a single ethnic group and that global mandibular skeletal parameters (e.g., retromolar area width, gonial angle) were not evaluated may limit the generalizability of the findings. Conclusion Within the scope of this CBCT-based study, it was determined that the lingual cortical plate adjacent to impacted mandibular third molars is often thin, particularly at the apical level; however, preoperative perforation is rarely observed. Lingual cortical thinning was found to be associated with impaction characteristics in univariate analyses, while age was identified as the sole independent predictor of lingual cortical perforation in multivariate logistic regression analysis. These findings suggest that age-related cortical changes may increase the fragility of the lingual plate even in relatively young populations. Clinically, the frequent extreme thinness of the apical lingual cortex emphasizes the importance of detailed CBCT evaluation in the preoperative period, especially in patients with deep impaction and advanced age. This approach may contribute to reducing complications such as lingual plate fracture, displacement of root fragments into adjacent anatomical spaces, and possible nerve injury. Declarations Acknowledgements Not applicable. Authors’ contributions Conceptualization, S.K. and O.Ş.; methodology, S.K., O.Ş., S.B. and S.N.M.; software, S.K. and O.Ş.; validation, S.K., O.Ş., S.B. and S.N.M.; formal analysis, S.K., O.Ş., S.B. and S.N.M.; investigation, S.K. and O.Ş.; resources, S.K. and O.Ş.; data curation, S.K. and O.Ş.; writing—original draft preparation, S.K. and O.Ş.; writing—review and editing, S.K. and O.Ş.; visualization, S.K.; supervision, O.Ş. All authors have read and agreed to the published version of the manuscript. Funding Not applicable. Data availability The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Ethics approval and consent to participate All the procedures of the study were in accordance with the Declaration of Helsinki and approved by Health Sciences Ethics Committee of Van Yuzuncu Yil University (date 16.05.2025-Approval no 2025/05-13). This study has been evaluated as a retrospective study by the Van Yuzuncu Yil University Non-Interventional Clinical Research Ethics Committee, and it has been determined that obtaining informed consent is not required for retrospective studies in accordance with Law No. 5846 and the Fundamental Law on Health Services No. 3359. As retrospective studies are conducted by reviewing existing patient records and past data that have been anonymized, obtaining informed consent is not obligatory under the relevant legislation. During the research process, personal data protection and confidentiality principles have been strictly adhered to. Consent for publication Not applicable. Competing interests The authors declare no competing interests. References Zhang J, Zhang K, Zhou X, Ye L, Liu Y, Peng Y, et al. Full life cycle changes of low impacted mandibular third molar associated cystic lesions and adjacent tooth root resorption: a retrospective study. 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Measurement of lingual cortical plate thickness and lingual position of lower third molar roots using cone beam computed tomography. J Int Soc Prev Community Dent. 2017;7(Suppl 1):S8–12. 10.4103/jispcd.JISPCD_106_17 . Zhao J, Wu XB, Liu N, Hao XH. Study on the thickness and morphology of lingual bone of impacted mandibular third molar based on CBCT and Simplant 3D reconstruction. Shanghai Kou Qiang Yi Xue. 2023;32:661–7. Segantin JF, Bisson GB, Chihara LL, Ferreira Júnior O. Tomographic analysis of relationship of mandibular morphology and third molars eruption. BMC Oral Health. 2023;23:915. 10.1186/s12903-023-03653-0 . Gao Q, Zhou X, Zhao Z, Chen B, Huang M, Lin H, et al. Comparison of the mandibular retromolar space in adults with different sagittal skeletal types and eruption patterns of the mandibular third molar: a cone-beam computed tomography study. BMC Oral Health. 2024;24:1112. 10.1186/s12903-024-04815-4 . Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8285559","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":566313457,"identity":"a6af8913-7e5a-42c4-b70b-614ef75b517c","order_by":0,"name":"Onur ŞAHAR","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0ElEQVRIiWNgGAWjYPCCAwwM7A1A2sCCFC08B0BaJEjRIpEAYhChhV+6x+zjj5o78uYzn1/d8KNAgoG/vTsBrxbJOWeMZ/Mce2Y453ZO2c0eoMMkzpzdgFeLwY0cY2YGtsOMM6Rz0m7wALUYSOQS1sL4499h+xmSZ9Ju/iFWCwNv2+HEGRLsx24TZYvkjLRiZt6+w8kzeHLYbssYSPAQ9Au/RPJmxh/fDtvOYD/+7OabPzZy/O29+LUgAR4DMEmschBgf0CK6lEwCkbBKBhBAADloUafWPUyOAAAAABJRU5ErkJggg==","orcid":"","institution":"Van Yüzüncü Yıl University","correspondingAuthor":true,"prefix":"","firstName":"Onur","middleName":"","lastName":"ŞAHAR","suffix":""},{"id":566313458,"identity":"bae1b98d-2ab9-49c9-86b6-42a467d9b762","order_by":1,"name":"Sema KAYA","email":"","orcid":"","institution":"Van Yüzüncü Yıl University","correspondingAuthor":false,"prefix":"","firstName":"Sema","middleName":"","lastName":"KAYA","suffix":""},{"id":566313459,"identity":"13b923c3-d86a-4ce4-9fca-07f658f6c2fc","order_by":2,"name":"Sıla Nazlıcan 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01:13:41","extension":"html","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":111864,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8285559/v1/cc74a4fed4ffbef444c83a57.html"},{"id":99259825,"identity":"b3c23e86-0b69-44ad-bef1-1ed5a4a820ad","added_by":"auto","created_at":"2025-12-31 01:13:41","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":401459,"visible":true,"origin":"","legend":"\u003cp\u003eCBCT images demonstrating Winter’s classification of impacted mandibular third molars: (A) vertical, (B) mesioangular, (C) horizontal, (D) distoangular, (E) buccolingual, and (F) other.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8285559/v1/ccdab25078c1a413ccc5f9c5.png"},{"id":99320865,"identity":"65fc3a48-d2fe-44b6-b7c1-57aa50401c86","added_by":"auto","created_at":"2025-12-31 16:38:55","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2104833,"visible":true,"origin":"","legend":"\u003cp\u003eCBCT images showing the depth of impaction according to the Pell and Gregory classification: (A) Level A, (B) Level B, and (C) Level C.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8285559/v1/42842fff1b0dd8c47adac372.png"},{"id":99259831,"identity":"d07a2ee4-5772-4426-beee-4e3d4495ae1f","added_by":"auto","created_at":"2025-12-31 01:13:41","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1779164,"visible":true,"origin":"","legend":"\u003cp\u003eCBCT images illustrating the ramus relationship of impacted mandibular third molars according to the Pell and Gregory classification: (A) Class I, (B) Class II, and (C) Class III.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8285559/v1/cc2d51d363caaecaa9dc4c81.png"},{"id":99320018,"identity":"e17eca56-b7d4-4d49-8f8f-5dca711595df","added_by":"auto","created_at":"2025-12-31 16:38:05","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1887510,"visible":true,"origin":"","legend":"\u003cp\u003eCBCT-based distance measurements from the impacted mandibular third molar to the lingual cortical bone: (A) distance from the cementoenamel junction of the third molar to the lingual cortical bone, and (B) distance from the most apical point of the distal root of the third molar to the lingual cortical bone.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8285559/v1/7148659bdcca52fa19cc9db4.png"},{"id":100363095,"identity":"c269e73c-3737-47d4-aa1c-d408ba14436d","added_by":"auto","created_at":"2026-01-16 07:48:53","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7214582,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8285559/v1/1f2dc1b9-f340-4473-9a03-67a32f753920.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"CBCT assessment of lingual cortical plate morphology and pre-existing perforation in impacted mandibular third molars","fulltext":[{"header":"Introduction","content":"\u003cp\u003eImpacted mandibular third molars are among the most common conditions encountered in oral and maxillofacial surgery and are associated with a wide variety of local complications, including pericoronitis, distal cervical caries of the second molar, root resorption, periodontal defects, cysts, and tumors [\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. More serious but less common sequelae include mandibular fractures affecting the inferior alveolar and lingual nerves and neurosensory disorders [\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe lingual cortical plate adjacent to the mandibular third molar tooth plays a critical protective role for the lingual nerve and submandibular spaces. Excessive force or incorrect elevation during third molar surgery can cause fracture of the lingual plate or displacement of root fragments beyond the cortex, potentially leading to lingual nerve injury and difficult surgical recovery [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Recent cone-beam computed tomography (CBCT) studies have emphasized that pre-existing discontinuities of the lingual cortex may be present prior to surgery, suggesting that some postoperative cortical \u0026ldquo;defects\u0026rdquo; represent anatomical variations rather than iatrogenic injury [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCBCT has become the preferred three-dimensional imaging method for evaluating impacted mandibular third molars because it provides three-dimensional information about root morphology, the mandibular canal, and the bucco-lingual dimensions of the bone surrounding this canal [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Several CBCT-based studies have focused specifically on the lingual plate in the third molar region. Wang et al. classified the topographic relationship between the root apex and the lingual plate of mesial and horizontal impacted mandibular third molars as non-contact, contact, and perforation, and identified impacted depth and lingual plate morphology as important risk factors for root-cortex contact or perforation [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Amin et al. reported a relatively high incidence of pre-existing lingual cortex perforation in their study and emphasized the importance of recognizing such defects on CBCT prior to surgery [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMultiple CBCT studies have demonstrated that the lingual cortical thickness surrounding impacted mandibular third molars is frequently\u0026thinsp;\u0026lt;\u0026thinsp;1 mm, particularly in the apical region. Previous investigations reported that both coronal and apical cortical thickness values generally remain below 1 mm, and that thinner plates are associated with higher rates of crown and root perforation. Moreover, lingual plate thickness and density have been shown to vary significantly depending on impaction angulation, depth, and root number, and a negative correlation between bucco-lingual tooth position and lingual cortical thickness has also been reported [\u003cspan additionalcitationids=\"CR17 CR18\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite this growing body of evidence, several important questions remain unanswered. First, while many studies have emphasized the distances between the tooth and the lingual plate or categorical root-cortex relationships, fewer studies have separately presented detailed measurements of lingual cortical thickness at the coronal and apical levels around impacted mandibular third molars [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Second, existing data on the effect of patient-related factors such as age and sex on lingual cortical thinning and perforation are inconsistent; some authors found no effect of age, while others suggested potential age-related changes in cortical morphology [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eGiven these limitations, the aim of this study is to analyze the relationship between the existing CBCT study, (i) by measuring the lingual cortical bone thickness at the coronal and apical levels, (ii) to determine the prevalence of pre-existing lingual cortex perforation, and (iii) to analyze the relationship between lingual cortical thickness and perforation with age, sex, side, impaction type (Winter classification), depth (Pell and Gregory classification), and root morphology. The authors hypothesized that the apical lingual cortex would be thinner than the coronal cortex, that pre-existing perforation would be associated with reduced cortical thickness, and that age and impaction characteristics would significantly affect lingual cortical morphology.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cp\u003eThis retrospective cross-sectional study was conducted using CBCT scans obtained for the diagnostic evaluation of impacted mandibular third molars. The study was conducted in accordance with medical protocols and the principles of the Declaration of Helsinki. Ethical approval for the study was obtained from the Clinical Research Ethics Committee of Van Yuzuncu Yil University (approval no. 2025/05\u0026ndash;13, May 16, 2025) and was conducted between May 2025 and October 2025 at the Oral and Maxillofacial Surgery and Dental and Maxillofacial Radiology clinics of Van Yuzuncu Yil University.\u003c/p\u003e \u003cp\u003eA post-hoc power analysis for the logistic regression model assessing the risk of perforation development was performed using G*Power 3.1 software. The Wald test z-statistic z\u0026thinsp;=\u0026thinsp;2.88 for the age variable found to be significant in the model, the total sample size N\u0026thinsp;=\u0026thinsp;201, and the significance level α\u0026thinsp;=\u0026thinsp;0.05 were included in the analysis. The calculated effect size based on these values was Odds Ratio\u0026thinsp;=\u0026thinsp;1.306 (β\u0026thinsp;=\u0026thinsp;0.267), and according to the G*Power output, the post-hoc power of the model was found to be in the range of 85\u0026ndash;88%. This result indicates that the logistic regression model predicting the risk of perforation based on the age variable has a high level of statistical power.\u003c/p\u003e \u003cp\u003eA total of 201 patients with an impacted third mandibular tooth were included in the study. Patients ranged in age from 14 to 53 years, with a mean age of 21.10\u0026thinsp;\u0026plusmn;\u0026thinsp;6.97 years. Inclusion criteria: The presence of an impacted mandibular third molar tooth requiring CBCT imaging; the availability of high-quality CBCT images in which the entire lingual cortical plate, the crown portion of the tooth, and the root apex are clearly visible; the absence of metallic artifacts or motion artifacts affecting the posterior mandible; and the analysis of only one tooth per patient to prevent clustering. Exclusion criteria: Patients with a history of mandibular surgery, trauma, fracture, cyst, tumor, osteolytic lesions, or developmental anomalies; systemic diseases known to affect bone density or quality (e.g., osteoporosis, metabolic bone disease); CBCT scans containing artifacts or where the lingual plate cannot be fully visualized, and impacted or partially impacted third molars.\u003c/p\u003e \u003cp\u003eThe KaVo 3D eXam (Biberach, Germany) tomography device was used for CBCT measurements. Individuals are seated during CBCT scans. The device self-calibrates before each image acquisition. Additionally, to standardize CBCT images, the Frankfurt plane is parallel to the horizontal plane, and the teeth are in centric occlusion and maximum intercuspation. Furthermore, to restrict patient movement, we use a special mandibular chin strap and cephalostats to stabilize the head. All tomography procedures were performed at 120 kVp, 5 mAs, 7 s scan time, 0.125-0.4 mm voxel size, and l30 mm FOV. This modification applies to all CBCT images, including coronal, sagittal, and axial images. CBCT images of axial and sagittal sections converted to Digital Imaging and Communications in Medicine (DICOM) formats were examined. A voxel size of 0.4 mm was used in this study. Lingual bone thickness calculations were performed using the eXam Vision program (Biberach, Germany).\u003c/p\u003e \u003cp\u003eThe radiometric evaluations within the scope of the study were performed on cross-sectional images obtained from CBCT scans. Prior to analysis, the images were reoriented according to standard anatomical planes in the multiplanar reconstruction (MPR) mode and aligned with the long axis of the tooth as a reference. To determine the anatomical relationship between the lingual cortical bone and the impacted mandibular third molar teeth, sections passing through the cementoenamel junction and root apex of the tooth were examined. At these determined levels, the shortest distance between the lingual surface of the tooth and the inner surface of the lingual cortical bone was measured in millimeters. In addition to quantitative measurements, the integrity of the lingual cortex was assessed, and any discontinuity or loss of integrity at the cortical bone margins was recorded as the presence of \u0026ldquo;perforation.\u0026rdquo;\u003c/p\u003e \u003cp\u003eInterobserver reliability for linear measurements was assessed using the two-way random-effects model with absolute agreement [ICC (2,1)]. For CEJ measurements obtained by the two observers, the intraclass correlation coefficient was ICC\u0026thinsp;=\u0026thinsp;0.936, whereas for apical measurements the ICC was 0.963, indicating excellent interobserver agreement for both parameters.\u003c/p\u003e \u003cp\u003eFor the categorical assessment of lingual cortical perforation (present/absent), interobserver reliability was evaluated using Cohen\u0026rsquo;s kappa coefficient. The two observers provided identical ratings for all 20 cases (2 \u0026ldquo;present\u0026rdquo;, 18 \u0026ldquo;absent\u0026rdquo;), yielding a kappa value of κ\u0026thinsp;=\u0026thinsp;1.00, which reflects perfect agreement.\u003c/p\u003e \u003cp\u003eAll impacted mandibular third molars were classified according to their angulation, depth of impaction and root morphology based on CBCT images. Tooth angulation was determined using Winter\u0026rsquo;s classification (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) and categorised as mesioangular, vertical, horizontal or distoangular according to the long axis of the third molar relative to the second molar. The depth of impaction was assessed using the Pell and Gregory classification (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), based on the relationship of the occlusal surface of the third molar to the occlusal plane of the second molar, and teeth were classified as Class A, Class B or Class C. In addition, root morphology (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) was evaluated on CBCT images and categorised as single root, fused roots, or separated multiple roots. All classifications were performed on multiplanar reconstructed CBCT sections by an experienced oral and maxillofacial radiologist under standardised viewing conditions.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analyses\u003c/h2\u003e \u003cp\u003eAll statistical analyses were performed using IBM SPSS Statistics (Version 25). The normality of the continuous variables was assessed with the Shapiro\u0026ndash;Wilk test, and since the data did not show a normal distribution pattern, non-parametric statistical methods were employed. Descriptive statistics were presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD), minimum, and maximum values.\u003c/p\u003e \u003cp\u003eComparisons of lingual cortical bone thickness between two independent groups (sex and side) were conducted using the Mann\u0026ndash;Whitney U test. The relationship between the presence of lingual cortical perforation and bone thickness at coronal, apical, and overall levels was also evaluated using the Mann\u0026ndash;Whitney U test. Comparisons involving more than two groups (age decades, Winter\u0026rsquo;s angulation types, Pell \u0026amp; Gregory depth classification, and root morphology) were analyzed using the Kruskal\u0026ndash;Wallis test, and significant findings were further interpreted through mean rank distributions.\u003c/p\u003e \u003cp\u003eTo identify predictors of lingual cortical perforation, a binary logistic regression analysis was performed. Age, sex, root morphology, Winter\u0026rsquo;s classification, and Pell \u0026amp; Gregory depth were included as independent variables in the model. The level of statistical significance was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 201 CBCT scans of impacted mandibular third molars were evaluated in this study. The mean age of the participants was 21.10\u0026thinsp;\u0026plusmn;\u0026thinsp;6.97 years (range: 14\u0026ndash;53 years). The mean lingual cortical bone thickness was 2.04\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12 mm at the coronal level and 0.86\u0026thinsp;\u0026plusmn;\u0026thinsp;0.80 mm at the apical level. The overall mean lingual bone thickness, calculated from these measurements, was 1.45\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70 mm (range: 0.24\u0026ndash;3.72 mm). The mean number of roots per tooth was 1.84\u0026thinsp;\u0026plusmn;\u0026thinsp;0.37 (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\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\u003eDescriptive statistics of demographic data and lingual cortical bone thickness measurements\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMin \u0026ndash; Max\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\u003eAge (Years)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e201\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e21.10\u0026thinsp;\u0026plusmn;\u0026thinsp;6.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14\u0026ndash; 53\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCoronal Lingual Bone Thickness (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e201\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e2.04\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u0026ndash; 5.39\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eApical Lingual Bone Thickness (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e201\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.86\u0026thinsp;\u0026plusmn;\u0026thinsp;0.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u0026ndash;4.97\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOverall Mean Bone Thickness (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e201\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.45\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.24\u0026ndash;3.72\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNumber of Roots\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e201\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.84\u0026thinsp;\u0026plusmn;\u0026thinsp;0.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u0026ndash; 2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003eN: Sample Size, SD:Standard Deviation, Min: Minimum, Max:Maximum.\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003eComparison according to sex and impaction side\u003c/h3\u003e\n\u003cp\u003eThe Mann\u0026ndash;Whitney U test revealed no significant association between sex and lingual cortical bone thickness. Coronal (Z = \u0026minus;\u0026thinsp;1.298; p\u0026thinsp;=\u0026thinsp;0.19), apical (Z = \u0026minus;\u0026thinsp;0.237; p\u0026thinsp;=\u0026thinsp;0.81), and overall mean thickness values (Z = \u0026minus;\u0026thinsp;0.967; p\u0026thinsp;=\u0026thinsp;0.33) did not differ significantly between females and males.\u003c/p\u003e \u003cp\u003eSimilarly, impaction side (right/left) did not significantly influence coronal (Z = \u0026minus;\u0026thinsp;0.045; p\u0026thinsp;=\u0026thinsp;0.96), apical (Z = \u0026minus;\u0026thinsp;0.955; p\u0026thinsp;=\u0026thinsp;0.34), or overall thickness (Z = \u0026minus;\u0026thinsp;0.443; p\u0026thinsp;=\u0026thinsp;0.66) values, indicating bilateral symmetry (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\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\u003e\u003cb\u003eComparison of lingual cortical bone thickness according to sex and side\u003c/b\u003e\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=\"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=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGroups\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCoronal MR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eApical\u003c/p\u003e \u003cp\u003eMR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eP*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eOverall MR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eP*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eSex\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eFemale\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e124\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e96.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e101.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e97.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.33\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eMale\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e107.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e99.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e106.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSide\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eRight\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e102\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e101.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e104.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e102.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.66\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\u003e\u003cb\u003eLeft\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e97.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e99.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003ePerforation\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eStatus\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003ePresent\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e24.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003e0.02\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e19.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003e0.01\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eAbsent\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e198\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e101.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e102.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e102.24\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003e\u003cem\u003eN: Sample Size, MR: Mean Rank, *Mann-Whitney U Test, 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\n\u003ch3\u003eComparison according to lingual cortex perforation\u003c/h3\u003e\n\u003cp\u003eA significant difference was found between individuals with and without lingual cortex perforation. Apical lingual bone thickness (Z = \u0026minus;\u0026thinsp;2.295; p\u0026thinsp;=\u0026thinsp;0.02) and overall mean thickness (Z = \u0026minus;\u0026thinsp;2.455; p\u0026thinsp;=\u0026thinsp;0.01) were significantly lower in the perforation group. However, coronal thickness did not differ significantly between groups (Z = \u0026minus;\u0026thinsp;1.860; p\u0026thinsp;=\u0026thinsp;0.063) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003ch3\u003eComparison among age groups\u003c/h3\u003e\n\u003cp\u003eThe Kruskal\u0026ndash;Wallis test demonstrated a significant difference in apical thickness among age groups (χ\u0026sup2; = 11.053; p\u0026thinsp;=\u0026thinsp;0.026). Although coronal bone thickness did not reach statistical significance (χ\u0026sup2; = 9.383; p\u0026thinsp;=\u0026thinsp;0.052), the p-value approached the significance threshold and the mean rank of the oldest group (Group 5: 28.20) was notably lower, suggesting a potential decline in coronal bone support with age. No significant differences were found for overall mean bone thickness among age groups (p\u0026thinsp;=\u0026thinsp;0.403) (Table\u0026nbsp;3).\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eComparison according to angulation type\u003c/h2\u003e \u003cp\u003eAngulation type significantly affected coronal lingual bone thickness (χ\u0026sup2; = 7.999; p\u0026thinsp;=\u0026thinsp;0.05) and overall mean thickness (χ\u0026sup2; = 9.066; p\u0026thinsp;=\u0026thinsp;0.03). The highest coronal values were observed in mesioangular impactions (Mean Rank: 106.13), while the highest overall mean values occurred in horizontal impactions (Mean Rank: 123.71). Vertical and distoangular impactions showed lower mean ranks, indicating reduced lingual bone support. No significant difference was detected in apical thickness among angulation types (p\u0026thinsp;=\u0026thinsp;0.314) (Table\u0026nbsp;3).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eComparison according to Pell \u0026 Gregory depth classification\u003c/h3\u003e\n\u003cp\u003eA significant association was found between impaction depth and coronal bone thickness (χ\u0026sup2; = 6.403; p\u0026thinsp;=\u0026thinsp;0.41). Level B showed the greatest coronal thickness (Mean Rank: 113.88), whereas Level C demonstrated the lowest (Mean Rank: 91.95). No significant differences were detected for apical (p\u0026thinsp;=\u0026thinsp;0.224) or overall mean thickness (p\u0026thinsp;=\u0026thinsp;0.213) values among the depth groups (Table\u0026nbsp;3).\u003c/p\u003e\n\u003ch3\u003eComparison according to root morphology\u003c/h3\u003e\n\u003cp\u003eRoot morphology (single root, fused roots, separated roots) did not significantly affect lingual cortical bone thickness. No significant differences were detected in coronal (χ\u0026sup2; = 3.755; p\u0026thinsp;=\u0026thinsp;0.153), apical (χ\u0026sup2; = 2.155; p\u0026thinsp;=\u0026thinsp;0.340), or overall thickness (χ\u0026sup2; = 2.034; p\u0026thinsp;=\u0026thinsp;0.362) values (Table\u0026nbsp;3).\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003ePredictors of lingual cortex perforation\u003c/h2\u003e \u003cp\u003eLogistic regression analysis identified age as a significant predictor of lingual cortex perforation (p\u0026thinsp;=\u0026thinsp;0.004). Each one-year increase in age raised the perforation risk by 1.306 times (Odds Ratio: 1.306; 95% CI: 1.088\u0026ndash;1.568). Sex was not a significant predictor (p\u0026thinsp;=\u0026thinsp;0.927).\u003c/p\u003e \u003c/div\u003e\u003cp\u003e\u003cstrong\u003eTable-3:\u003c/strong\u003e \u003cstrong\u003eEvaluation of lingual cortical bone thickness according to age groups, Winter\u0026rsquo;s classification, Pell \u0026amp; Gregory depth classification, and root morphology\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 107px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroups\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eN\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCoronal MR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eApical\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOverall MR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 107px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge Group\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.Dekad\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e123\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e103.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e107.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.03\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e105.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.Dekad\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e104.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e89.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e97.98\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e3.Dekad\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e80.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e104.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e89.50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e4.Dekad\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e90.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e16.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e65.50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e5.Dekad\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e28.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e122.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e67.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" style=\"width: 107px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWinter\u0026rsquo;s Classification\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMesioangular\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e155\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e106.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e46\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e102.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e314\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e104.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVertical\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e76.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e85.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e75.93\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHorizontal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e104.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e120.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e123.71\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDistoangular\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e66.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e95.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e70.10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 107px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePell \u0026amp; Gregory Depth\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eClass A\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e97.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e84.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e224\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e89.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e213\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eClass B\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e113.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e97.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e109.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eClass C\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e104\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e91.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e106.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e96.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 107px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRoot Morphology\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSingle\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e83.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e153\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e117.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 44px;\"\u003e\n \u003cp\u003e340\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e95.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e362\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFused\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e116.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e98.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e117.79\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSeparate\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e156\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e101.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 68px;\"\u003e\n \u003cp\u003e98.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e99.53\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eN: Sample Size, MR: Mean Rank, *Kruskal Wallis Test, p\u0026lt;0.05.\u003c/em\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis CBCT-based study evaluated the lingual cortical plate adjacent to impacted mandibular third molars in a sample of 201 patients and demonstrated that the lingual cortex is frequently thin, particularly at the apical level, whereas pre-existing perforation is uncommon.\u003c/p\u003e \u003cp\u003e The mean coronal and apical lingual cortical thickness values obtained in this study (2.04 mm and 0.86 mm, respectively) are consistent with the results of previous CBCT studies reporting that the lingual plate gradually thins toward the root apex. Studies have reported that apical lingual cortical thickness falls below 1 mm in most cases and have emphasized that this region is structurally weak [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Wang et al. and Gumber et al. have indicated that this apical thinning causes the lingual plate to become more susceptible to fracture during tooth elevation and surgical manipulations [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The significant thinning of the apical cortex observed in our study once again highlights the clinical importance of preoperative CBCT evaluation, particularly in cases of deep impaction.\u003c/p\u003e \u003cp\u003eIn this study, preoperative lingual cortical perforation was detected in only 1.5% of cases, which is significantly lower than the perforation rates reported in other studies [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. This difference may be due to differences in the population characteristics of the studies, the presence of impacted teeth in the sample, and the radiological criteria used to define perforation. However, the finding of significantly lower apical and overall cortical thickness in cases with perforation is consistent with previous studies showing that perforation is associated with severe cortical thinning and concavity [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIt has been demonstrated that lingual cortical morphology can vary depending on the characteristics of impaction. Several CBCT studies have reported that horizontal and mesioangular impactions are more frequently associated with thin lingual plate or direct root\u0026ndash;cortical contact due to the root apex being positioned closer to the lingual cortical surface [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Dumanlı et al. also reported the highest perforation rates in horizontal impactions [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Although the Winter classification and Pell \u0026amp; Gregory depth classification did not emerge as independent predictors of perforation in the logistic regression analysis in the present study, they showed significant correlations with lingual cortical thickness in univariate analyses. This suggests that the impaction position affects lingual bone morphology, but this effect may be overshadowed by stronger predictors such as age.\u003c/p\u003e \u003cp\u003eOne of the most important findings of this study is that age was identified as the sole independent predictor for lingual cortical perforation. Age-related changes in mandibular cortical morphology have been discussed in various radiological and morphological studies. Zhao et al. demonstrated that lingual bone thickness and morphology can vary with age and skeletal pattern. Halder et al. reported age-related changes in bone density and thickness in the lingual plate region [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. In contrast, Amin et al. did not find a significant relationship between age and perforation [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. First and foremost, the demographic profile of our study population was predominantly young (mean age: 21.10\u0026thinsp;\u0026plusmn;\u0026thinsp;6.97 years). Since our multivariate analysis identified age as a significant predictor of perforation, it is plausible that the lower incidence is a direct reflection of the younger cohort, whereas studies including older populations would naturally exhibit higher perforation rates due to age-related bone remodeling. Second, ethnic variations in skeletal structure and bone density may play a role; our sample consisted of a specific ethnic group in Eastern Anatolia, which may differ from the populations analyzed in other studies. Finally, the voxel size used in CBCT imaging is a critical technical factor. We utilized a voxel size of 0.4 mm, which is standard for clinical assessment; however, studies utilizing higher resolution protocols (smaller voxel sizes) might be more sensitive in detecting micro-perforations that are not visible at 0.4 mm, potentially explaining the higher rates reported elsewhere.\u003c/p\u003e \u003cp\u003eSex, side, and root morphology did not show a significant relationship with lingual cortical thickness or perforation. These results are consistent with findings from previous CBCT studies indicating that these variables are not as determinative of lingual cortical morphology as impaction depth, tooth angulation, and individual cortical anatomical structure [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eRecent studies have examined the relationship between third molar impaction and mandibular morphology, demonstrating significant correlations between the retromolar space, mandibular skeletal shape, and the likelihood of impaction [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Although these studies did not directly measure lingual cortical thickness, they complement the findings of the present study by emphasizing the effect of mandibular anatomical structure on impaction and surgical difficulty. This study, however, focuses on the lingual cortical plate, a critical region directly related to surgical complications, thereby providing a unique and clinically significant contribution to the literature.\u003c/p\u003e \u003cp\u003e From a clinical perspective, the fact that the apical lingual cortex is often less than 1 mm thick indicates the need for careful manipulation during elevation and the necessity to avoid excessive lingual force, particularly in elderly patients and those with deep impaction. Even in the absence of perforation, an excessively thin cortex may increase the risk of lingual plate fracture or displacement of root fragments into the submandibular or sublingual spaces. Such complications have also been reported in previous surgical complication studies [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Therefore, detailed preoperative CBCT evaluation to identify high-risk anatomical configurations is strongly recommended for safer surgical planning.\u003c/p\u003e \u003cp\u003eThe methodological strengths of this study include a relatively large sample size, standardized two-level (coronal and apical) lingual cortical thickness measurements, and the use of multivariate logistic regression analysis to identify independent predictors of perforation. Additionally, the inclusion of parameters closely related to surgical difficulty, such as Winter impaction classification, Pell \u0026amp; Gregory depth and ramus relationship classifications, and root morphology, in the same analysis model has enabled a more comprehensive assessment of anatomical factors that may influence lingual cortical morphology.\u003c/p\u003e \u003cp\u003eThe study also has some limitations. The retrospective design does not allow for complete control over patient selection, and CBCT images were obtained for clinical indications rather than for research purposes. Furthermore, since lingual cortical integrity was not confirmed intraoperatively, it was not possible to directly correlate radiological findings with actual surgical complications. Another critical limitation concerns the statistical power regarding the analysis of predictors for perforation. Since the prevalence of pre-existing perforation was quite low in our sample (1.5%, n\u0026thinsp;=\u0026thinsp;3), the logistic regression results identifying age as a predictor should be interpreted with caution due to the limited number of events. Moreover, our study population consisted predominantly of young adults (mean age: 21.10\u0026thinsp;\u0026plusmn;\u0026thinsp;6.97 years), with fewer participants in advanced age groups. In addition, the fact that the study was conducted in a single ethnic group and that global mandibular skeletal parameters (e.g., retromolar area width, gonial angle) were not evaluated may limit the generalizability of the findings.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWithin the scope of this CBCT-based study, it was determined that the lingual cortical plate adjacent to impacted mandibular third molars is often thin, particularly at the apical level; however, preoperative perforation is rarely observed. Lingual cortical thinning was found to be associated with impaction characteristics in univariate analyses, while age was identified as the sole independent predictor of lingual cortical perforation in multivariate logistic regression analysis. These findings suggest that age-related cortical changes may increase the fragility of the lingual plate even in relatively young populations.\u003c/p\u003e \u003cp\u003eClinically, the frequent extreme thinness of the apical lingual cortex emphasizes the importance of detailed CBCT evaluation in the preoperative period, especially in patients with deep impaction and advanced age. This approach may contribute to reducing complications such as lingual plate fracture, displacement of root fragments into adjacent anatomical spaces, and possible nerve injury.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization, S.K. and O.Ş.; methodology, S.K., O.Ş., S.B. and S.N.M.; software, S.K. and O.Ş.; validation, S.K., O.Ş., S.B. and S.N.M.; formal analysis, S.K., O.Ş., S.B. and S.N.M.; investigation, S.K. and O.Ş.; resources, S.K. and O.Ş.; data curation, S.K. and O.Ş.; writing\u0026mdash;original draft preparation, S.K. and O.Ş.; writing\u0026mdash;review and editing, S.K. and O.Ş.; visualization, S.K.; supervision, O.Ş. All authors have read and agreed to the published version of the manuscript. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;All the procedures of the study were in accordance with the Declaration of Helsinki and approved by Health Sciences Ethics Committee of Van Yuzuncu Yil University (date 16.05.2025-Approval no 2025/05-13). This study has been evaluated as a retrospective study by the Van Yuzuncu Yil University Non-Interventional Clinical Research Ethics Committee, and it has been determined that obtaining informed consent is not required for retrospective studies in accordance with Law No. 5846 and the Fundamental Law on Health Services No. 3359. As retrospective studies are conducted by reviewing existing patient records and past data that have been anonymized, obtaining informed consent is not obligatory under the relevant legislation. During the research process, personal data protection and confidentiality principles have been strictly adhered to.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Not applicable.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;The authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZhang J, Zhang K, Zhou X, Ye L, Liu Y, Peng Y, et al. Full life cycle changes of low impacted mandibular third molar associated cystic lesions and adjacent tooth root resorption: a retrospective study. 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BMC Oral Health. 2024;24:1112. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12903-024-04815-4\u003c/span\u003e\u003cspan address=\"10.1186/s12903-024-04815-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Impacted mandibular third molar, Lingual cortical plate, Cone-beam computed tomography, Lingual cortex perforation","lastPublishedDoi":"10.21203/rs.3.rs-8285559/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8285559/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eImpacted mandibular third molars may be associated with surgical complications related to the lingual cortical plate. However, detailed information on coronal and apical lingual cortical thickness and the factors influencing pre-existing lingual cortex perforation remains limited.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis retrospective cross-sectional study evaluated cone-beam computed tomography (CBCT) scans of 201 patients with impacted mandibular third molars. Lingual cortical thickness was measured at coronal and apical levels, and pre-existing perforation was recorded. Age, sex, side, angulation (Winter classification), impaction depth (Pell and Gregory classification), and root morphology were analyzed. Non-parametric tests were used for group comparisons, and binary logistic regression was performed to identify independent predictors of perforation.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eMean lingual cortical thickness was 2.04\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12 mm at the coronal level and 0.86\u0026thinsp;\u0026plusmn;\u0026thinsp;0.80 mm at the apical level, with an overall mean of 1.45\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70 mm. Pre-existing perforation was detected in 1.5% of cases. Apical (p\u0026thinsp;=\u0026thinsp;0.02) and overall thickness (p\u0026thinsp;=\u0026thinsp;0.01) were significantly lower in the perforation group. Angulation type significantly affected coronal (p\u0026thinsp;=\u0026thinsp;0.046) and overall thickness (p\u0026thinsp;=\u0026thinsp;0.028), and impaction depth was associated with coronal thickness (p\u0026thinsp;=\u0026thinsp;0.041). Sex, side, and root morphology showed no significant associations. Age was the only independent predictor of lingual cortex perforation (OR\u0026thinsp;=\u0026thinsp;1.306; 95% CI: 1.088\u0026ndash;1.568; p\u0026thinsp;=\u0026thinsp;0.004).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eThe lingual cortical plate adjacent to impacted mandibular third molars is frequently thin, particularly at the apical level, whereas pre-existing perforation is rare. Thinner cortex and increasing age significantly increase the risk of lingual cortical perforation. Detailed preoperative CBCT evaluation is essential for safer surgical planning.\u003c/p\u003e","manuscriptTitle":"CBCT assessment of lingual cortical plate morphology and pre-existing perforation in impacted mandibular third molars","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-31 01:13:36","doi":"10.21203/rs.3.rs-8285559/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"bf8ad249-c006-4b58-8eca-1ab7e1d77428","owner":[],"postedDate":"December 31st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-12T09:55:09+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-31 01:13:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8285559","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8285559","identity":"rs-8285559","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}