Three-dimensional relationship between the degree of bilateral impacted mandibular third molars angulation and the mandibular dental arch parameters: a cross-sectional comparative study

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Sharaf, Abbas Ahmed Abdulqader, Najah Alhashimi, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2365433/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 15 May, 2023 Read the published version in Clinical Oral Investigations → Version 1 posted 8 You are reading this latest preprint version Abstract Objectives: The purpose of this study was to three-dimensionally evaluate the relationship between the degree of bilateral impacted mandibular third molars (IM3M) angulation and the mandibular dental arch parameters in normal skeletal and dental malocclusion patients. Materials and Methods: In this retrospective cross-sectional comparative study, 120 adult subjects’ cone beam computed tomography (CBCT) images were three-dimensionally analyzed. The sample was divided into four groups according to degree of M3M buccolingual angulation (BL°); Group A 24° off center of the ridge (N=30), and Group D (control group with normal erupted bilateral M3M).The study subjects were further also divided into three groups according to IM3M mesiodistal angulation (MD°); Group 1 from10° to 45°, Group 2> 45° and Group 3 (control group with normal erupted bilateral M3M, 0 -10°). Comparison within and between groups were performed using One-way ANOVA followed by Tukey's post hoc test, respectively. Correlation between IM3M, BL and MD angulation and mandibular arch parameter was calculated using Pearson's correlation coefficient. Results: Statistically significant differences (P < .001) were founded between the IM3M BL° and anterior teeth inclination, arch length (AL) and inter second molar width (inter 2 nd MW) as well as between the IM3M MD° with anterior crowding and the arch length (P < .001). Significant positive correlation was founded between IM3M BL° and anterior teeth inclination, and between IM3M MD° and anterior teeth crowding and inter 2nd MW. Significant negative correlation was observed between IM3M BL° and inter 1 st MW and 2 nd MW. Conclusion: The degree of buccolingual and mesiodistal angulation of the impacted mandibular third molars was associated with mandibular dentoalveolar changes. The increase in buccolingual angulation is associated with increase of anterior teeth inclination, and the decrease of 1 st and 2 nd inter-molars width. The increase in mesiodistal angulations was associated with increase in anterior teeth crowding and 2 nd inter-molars width. Clinical relevance: Assessment of the relationship between the impacted mandibular third molars and the degree of arch discrepancy, and the position of mandibular incisors in the three planes of space might help in the decision-making process for extraction of the impacted third molars in adult patients. Buccolingual dental arch parameters impacted mandibular third molars mesiodistal relationship three-dimensional Figures Figure 1 Figure 2 Introduction Tooth eruption is considered to be a complex process; hence, tooth eruption can occur early, late, or even fail most of the time when the eruption of the tooth exceeds the scheduled time[ 1 ]. Third molar is the most commonly impacted tooth. The recorded frequency of its impaction varied greatly between populations, with the highest recorded in a Singapore Chinese population at 68.6%[ 2 ]. They are commonly in the mandible than maxillary arch, and females have a higher prevalence than males[ 3 ]. The correlation between mandibular incisor crowding and third molar has been a controversial issue for a long time in dentistry literature [ 4 ] . The most debated question is whether third molar impaction played a role in the development or recurrence of malocclusion. Despite the discussion of this topic take a place in literature , however the question of whether impacted third molar teeth contribute to anterior dental arch crowding remains unanswered, particularly when three-dimensional imaging modalities are used[ 5 ]. Panoramic radiography (PR) has been used as a diagnostic tool. However, because of this modality's two-dimensional nature, there are overlaps of anatomical regions that are important for making decisions, which increases the chance of error. Cone-beam computed tomography (CBCT) has enabled the generation of trans-sections (i.e., perpendicular to the tangent of the dental arch) and three-dimensional reconstructions from digital images in the axial, coronal, and sagittal dimensions. Its ability to capture the third dimension, the depth of the image and the lack of overlap between nearby anatomical components is what makes it unique[ 6 ]. CBCT enables us to determine tooth size and arch dimension as rapidly, reliably, correctly, and reproducibly as measurements obtained by the digital method on digitalized plaster models[ 7 , 8 ]. A number of factors contribute to late incisor crowding. The eruption of the lower third molars is regarded as the most important etiologic factor, followed by others such as tooth size, dental arch shape, retroclination of the lower incisors, skeletal and soft tissue growth changes, mesial movement of the posterior teeth, mandibular arch length and width, jaw-to-size ratio, mandibular growth pattern, gender, forces from periodontal fibers, and natural aging [ 9-12 ]. Niedzielska et al. came to the conclusion that inadequate retromolar space exacerbates malocclusion and dental crowding of lower anterior teeth, which is produced by the eruption of the third molar, indicating the significance of removing the third molar [ 13 ]. Lindauer et al. concluded that the mandibular molars are expected to be a cause of dental crowding by American orthodontists and oral and maxillofacial surgeons, and they recommended their removal[ 14 ]. According to a study by Seerab Husain utilising CBCT, there is a positive link between the crowding of the mandibular incisors and third molars, indicating that third molars are one of the etiological causes for crowding, if not the sole one[ 15 ]. On the other hand, Sidlauskas and Trakiniene evaluated 91 people with an average age of 21. In their study, crowding was assessed by comparing the mesiodistal widths of the individuals' teeth to the length of the corresponding segment of the mandibular dental arch. The authors did not report significant differences in mandibular dental arch crowding between the groups with erupted, unerupted, and agenesis of third molars. They came to the conclusion that third molars and late lower dental arch crowding are not related[ 16 ]. Harradine et al. reported similar results in orthodontic treatment subjects. In a randomized controlled study, they investigated the influence of third molar extraction on the development of the crowding in anterior mandibular segment. The results reveal a negligible difference between the groups (third molars extracted versus non-extracted) that is not statistically significant. Therefore, they concluded that the extraction of third molars to avoid or minimize late incisor crowding was not justifiable[ 11 ]. Even though a recently published systematic review reported that only 6 studies were selected in the quantitative synthesis and none of these studies used CBCT for evaluation of such 3D problem[ 17 ]. Thus, there is a great inconsistency in studies regarding to the relationship of IM3M and other dental arch parameters like anterior crowding, at the same time using more reliable diagnostic tool like 3D CBCT to add well designed study with comprehensive three-dimensional measurements to the existing literature. This study aimed to three-dimensionally evaluate the relationship between the degree of bilateral impacted mandibular third molars (IM3M) angulation and the mandibular dental arch parameters in normal skeletal and dental malocclusion patients. Materials And Methods Study design and participants: This study was designed as a retrospective cross-sectional comparative study that was carried out at the stomatology hospital, central south University, China. Patients must consent to participate in any trial and approve the use of their data, according to the institution’s policy, which includes a thorough description of the procedure’s advantages and risks. This study was approved by the committee of ethical and clinical scientific research at the hospital of stomatology, Central South University, China, (LYF2022130). This study included the patients who had undergone cone-beam computed tomography CBCT in the Second Xiangya Hospital of Central South University from 2019 to 2021. The inclusion criteria included the following: 1) age 20–30 years old, 2) skeletal Class I according to the Chinese norms; ANB = 2.7° ± 2.0°[18] and dental (canine/molar) Class I relationship, 3) complete permanent dentition, 4) lower third molar with completely formed roots, 5) reported healthy periodontium based on the recorded clinical records, and 6) high-quality CBCT volumetric data. While the exclusion criteria included: 1) missing or extra teeth, 2) abnormal tooth size and morphology, 3) previous orthodontic-surgical treatment, 4) incompletely formed roots, unilateral impacted or erupted M3M, 5) interproximal caries and dental restoration, crown and bridge, 6) noticeable alveolar bone loss, and 7) cleft lip and/ or palate. The control group cases characterized by fully formed and erupted bilateral M3M in normal or near normal eruption, buccolingual angulations less 12°, and mesiodistal angulation less 10°. Study sample size: G*power 3.0.10 software was used to determine the sample size with an alpha value of 0.05 and a power of 95% based on the study conducted by Hasegawa et al.[19], who reported Little’s index of irregularity of 1.66 ± 0.83 mm and 4.08 ± 1.61 mm in the normal and crowded subjects in their study aimed to ascertain whether the lower third molar can affect anterior crowding and/or the inclination of teeth in the lower lateral segments.. Power analysis showed a minimum sample of 18 subjects is to be included. However, the sample size was increased to a minimum 20 subjects for each study group. One hundred twenty young adult patients’ with well documented clinical and radiographic data fulfilled the selection criteria. The participants were divided into study group (N = 100): who have bilateral impacted M3M, the study group was further divided into three subgroups according to buccolingual inclination of the IM3M; Group A 24° off center of the ridge (N = 30).and control group (N = 20) with normal and fully erupted bilateral M3M. The control group included the participants who have bilateral eruption (E) M3M with buccolingual inclination less than 12°, mesiodistal angulations less than 10° in normal eruption[20]. Three-dimensional imaging: The following parameters were used for all CBCT imaging on an i-CAT instrument (imaging Sciences International Inc., Hatfield, PA, USA): Voxel size: 0.3 mm, Field of View (FOV): 16.0 cm 13.0 cm, Voltage: 120 kVp, Filament Current: 18.54 mAs, Total Scan Time: 8.9 s. Patients were told not to swallow while being scanned, and their heads were held in a conventional position with their teeth with maximal teeth intercuspation, the horizontal plane (HP) parallel to the ground. Digital Imaging and Communications in Medicine (DICOM) files were acquired and then imported into Invivo Anatomage version 6 software (Anatomage, San Diego, CA, United States) for 3D analysis. Outcomes assessment: The coordinate system's orientation is defined based on the face skeletal midline points of the Nasion (N), Anterior Nasal Spine (ANS), and Sella in order to acquire consistent alignment of the 3D images (S). The right Orbital (Or) point and two Porion (Pr) points serve as the lateral landmarks. Then, depending on the most obvious sites, the three-dimensional landmarks were digitally created. The skeletal reference line and measurements are presented in Table 1 . Table 2 shows the three-dimensional measurements of angulations of impacted (I) and eruption (E) third molar (IM3M) and dental arch parameters. Selected points in the three planes (sagittal, axial and coronal,) were individually adjusted using a slice locator. Angulations of third molar[21] and dental arch parameters[7] and inclination of anterior teeth[22] used in this study are presented in [Figures 1 and 2]. After grouping the study group into three sub-groups (GA, GB, and GC) according to the M3M buccolingual inclination, the means of dental arch anteroposterior and transverse parameters were compared with each other and with those in the control group. The M3M mesiodistal angulation was further divided into three groups according to the degree of angulation; Group 1 (MD°10–45°); Group 2(MD°๥45°) and Group 3 (control) less 10°[23]. Dental arch anteroposterior and transvers parameters were compared between mesiodistal groups. All parameters were statistically analyzed to determine the relationship between buccolingual and mesiodistal angulations of impacted and erupted M3M with the anteroposterior and transvers arch parameters. The definitions of skeletal and dental measurements are presented in Table 1 and 2 . Statistical Analysis Statistical analysis was performed using SPSS 26.0 (software (IBM Corp., Armonk, NY, USA). Continuous variables are expressed as a number of observations, mean and standard deviation. Categorical and discrete variables were presented by frequency and percentage. The Shapiro-Wilk test was used to test the normal distribution. The means of anteroposterior and transfer arch parameters were compared in both buccolingual M3M and mesiodistal M3M groups using One-way analysis of variance (ANOVA) followed by Tukey post hoc test to compare the mean values between the groups. The Pearson's correlation test was used to confirm the correlation between IM3M buccolingual and mesiodistal angulations and the anteroposterior and transfer arch parameters. Intra- and inter-class correlations were calculated to assess the reliability and reproducibility of the parameters. The P-value was set at 0.05 for significant differences. Results Both inter-observer and intra-observer reliability were excellent; detailed data are presented in supplementary material 1. The demographic data as well as the descriptive statistics presented in Table 3 . Regarding the M3M buccolingual angulations and anteroposterior parameters, One-way ANOVA revealed highly significant differences between the M3M BL° angulation and anterior teeth inclination (P < .001), arch length (P < .01), and inter 2nd MW (P < .001) as shown in Table 4 . The inter-group compressions revealed a significant difference in anterior teeth inclination between Group A and Group C, increased 7.2° in group C (P < .001), Group A and Group D, increased 5.1° in group D (P < .05), and Group B and Group C, increased 3.8° in group C (P < .05). Statistically significant difference was founded in arch length between Group A and Group D (P < .01), Group B and Group D (P < .01), and Group C and Group D (P < .05). For the M3M buccolingual angulation and transvers parameters, the difference in inter 2nd MW was statistically significant difference between Group A and Group B (P < .01), Group A and Group C (P < .001) Table 4 . The results of the M3M mesiodistal angulation and dental arch parameters, within group comparison have showed a statistically significant difference in arch length measurement (P < .001) table. Between group comparison has revealed a statistically significant difference in anterior teeth crowding between Group 2 and Group 3, increased 0.93 mm in group2 (P < .001), as well as, in arch length between Group 1 and Group 3, increased 1.9 mm in group1 (P < .001), and Group 2 and Group 3, increased 2.42 mm in group2 (P < .001). However, there is no significant difference between M3M MD° and transvers arch parameters (Table 5 ). The correlation between IM3M BL° and dental arch parameters was calculated in Table 6 . Significant positive correlation was founded between IM3M BL° and anterior teeth inclination ( P < .05), which means that the increase in degree of IMEM angulation lingually is associated with increasing of degree of anterior teeth buccal inclination. However significant negative correlation was founded between inter 1st MW, inter 2nd MW (P < .05 and P < .01, respectively). Interpretation normally For Correlation between IM3M MD° and dental arch parameters, significant positive correlation was founded between IM3M MD° and anterior teeth crowding ( P < .01), arch length ( P < .01), inter 2nd MW (P < .05). It means that the increase in the degree of IM3M mesiodistal angulation is associated with increasing in anterior teeth crowding, arch length and inter 2nd MW as showed in table 7. Discussion Crowding in the lower anterior teeth is among the most common malocclusions that lead to the need for orthodontic treatment since it affects an individual's esthetics and oral health. At the same time, recognizing the etiological factors of crowding and relapse in mandibular anterior teeth after treatment is considered an issue facing orthodontists[10, 20, 24]. It is still unclear if the lower third tooth has a role in these issues. Regardless, studies examining the association between the lower third molar and the different dental arch parameters using three-dimensional analyses are still lacking. As a result, this study aims to use a three-dimensional analysis to assess the relationship between the different angulations of the impacted third molar (buccal, lingual, mesial, and distal) and the degree of these angles with the anteroposterior and transverse arch parameters (crowding, arch length, arch width) in a patient with skeletal class I malocclusions. Richardson et al. examined the relationship between the original crowding and the changes in crowding after five years in individuals with both bilaterally impacted and erupted M3M, they concluded that the individuals with bilaterally impacted M3M tends to have more crowding of early permanent dentition, both anteriorly and posteriorly[25]. Similarly, Niedzielska et al. assessed lower incisor crowding and dental arch changes after three years in a sample with bilateral retained or extracted M3M. They found that retained M3M was associated with increased tooth crowding in relation to Ganss ratio[13]. Our study has examined the angulation of bilateral IM3M to analyze the relationship between the degree of that angulation and dental arch parameters. The present study found a statistically significant difference between IM3M MD °and anterior teeth crowding. These results confirm those reported in the previous studies that found a significant relation between bilaterally IM3M and lower anterior crowding. Furthermore, our results could support the hypothesis that the erupting third molars related to anterior teeth forward inclination and cause their crowding, as a significant difference was found between the IM3M MD°๥45° and the control group. Additionally, Pearson's correlation has supported that idea, a significant positive correlation between IM3M MD° anterior crowding was noticed, which means that the increasing angulation of IM3M mesially increases lower anterior teeth crowding. However, the results of the current study were contrary to those reported by Shanley et al. and Kaplan et al;[26, 27] who assessed the orthodontically untreated subjects with M3M. The previous authors didn’t find a significant difference between bilaterally impacted and erupted groups concerning the anterior teeth crowding. Although different in results between our study and the previous studies, we still agree that anterior crowding is a multifactorial phenomenon, and the effect of other factors cannot be ignored[16, 28]; the difference in results may be due to differences in population or measuring methods. The current study has observed a significant difference between IM3M buccolingual angulation and anterior teeth inclination, which means that the increase in IMEM angulation lingually increases anterior teeth labial inclination. At the same time, the angulation of IM3M lingually was significantly associated with decreasing in inter 2nd MW. This could be interpreted as the reduction in 2nd MW, maybe due to the reduced arch width in the examined samples; thus, the anterior teeth were proclined to compensate for the decrease in arch width. Furthermore, our study found a significant difference in arch length parameters between both IM3M BL° and MD° groups; the increasing degree of angulation mesially/lingually was associated with decreasing arch length. However, a significant positive correlation was found only between IM3M BL° and arch length. These results support the hypothesis that the impaction of M3M, consequently the crowding in anterior teeth, was related to an increase in tooth size[29, 30]. This was very clear in our study, where the arch length was significantly decreased in control (EM3M) group compared with the impacted (IM3M) groups. Finally, this study recorded a significant negative correlation between inter 1st and 2nd MW and IM3M ML°; this correlation was absent in BL° groups and was identical to the previous study that hypothesis that force excreted by IM3M may cause pushing or buccal rotation of second molars.[4] Limitations The sample size was one of the study's limitations. Although calculated in advance, a larger sample size is suggested, with a greater emphasis on male-female comparisons in all variables analyzed. Furthermore, we recommend more classification based on facial pattern (brachy, mesocephalic, or dolichocephalic) to assess any relationship in this regard, as mandible inclination may affect the tendency for more mesial pressure against the teeth. The ethnicity was another limitation as it was restricted to Chinese; results may differ if other ethnicities are included. In addition, the research team suggested that future studies use a mixed longitudinal design rather than a single point of observation. Conclusion The degree of IM3M BL° and MD° was associated with the changes anterior teeth crowding and inclination, arch length, and inter second molar width parameters. The increase in IM3M MD° angulations was associated with increase in anterior teeth crowding and inter 2nd MW.The Increasing of IM3M BL° inclination the increasing of anterior teeth inclination, and the decreasing of 1st MW, inter 2nd MW. Declarations Ethics approval and consent to participate LYF2022130 Consent for publication Not applicable Availability of data and material Not applicable Competing interests Not applicable Funding No Authors' contributions Contributions of author(s) Conception and design of study: Ohood Haider , Xiao Li Wei * . Acquisition of data: Chen Chen, Mufeed Ahmed Sharaf, Najah Alhashimi. Analysis and/or interpretation of data: Abbas Ahmed Abdulqader , Hassan Sherrhan, Chen Chen, Waleed Alsoufi . Drafting the manuscript: Ohood Haider , Mufeed Ahmed sharaf, Maged S. Alhammadi . Revising the manuscript critically for important intellectual content: Ohood Haider, Zeng Yun Ting, Maged S. Alhammadi, Xiao Li Wei *. Acknowledgements The authors would like to thank Prof. Feng Yun Zhi, Prof. Shen gao Huang and Dr. Bushra Sufyan Almaqrami for their consultations and assistance in accomplishing this study. 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Am J Orthod 66:411-30. doi: 10.1016/0002-9416(74)90050-5 S SL (1962) The influence of mandibular third molar on mandibular anterior teeth. Am J Orthod 48:786-787. Mohammad RJ (2021) The Relationship of Mandibular Wisdom Tooth Within the Crowding of Lower Anterior Teeth- A Literature Review. Journal of Research in Medical and Dental Science 9:160-165. Bishara SE, Jakobsen JR, Treder JE and Stasi MJ (1989) Changes in the maxillary and mandibular tooth size-arch length relationship from early adolescence to early adulthood. A longitudinal study. Am J Orthod Dentofacial Orthop 95:46-59. doi: 10.1016/0889-5406(89)90135-2 Bishara SE, Treder JE, Damon P and Olsen M (1996) Changes in the dental arches and dentition between 25 and 45 years of age. Angle Orthod 66:417-22. doi: 10.1043/0003-3219(1996)0662.3.Co;2 Tables Table 1 Definitions of skeletal references and measurements used in the study Skeletal Measurements Abb. Definition Horizontal plane HP A plane defined by three landmarks: right Orbitale and Porion and left Porion Mid-sagittal plane MSP A plane through Sella and Nasion and perpendicular to the horizontal plane. Vertical plane VP A plane through Sella and perpendicular to the horizontal plane and midsagittal plane. S–N plane S-N A plane constructed by two-points Sella, Nasion, and perpendicular on the horizontal plane. Mandibular plane MP A plane constructed by three-point two sides Gonion and Gnathion. ANB angle ANB The angle between three-point landmarks (A point, Nasion, and B point). Mandibular plane angle GO-GN/SN The angle between S–N plane and GO-GN plane. Table 2 Definitions of dental measurements used in the study Linear measurement Abb Definition Mesiodistal angle MD° The sagittal CBCT slice was used to calculate the mesiodistal angle of the impacted or erupted M3M by measuring the long axis of the third molar relative to the vertical axis through the erupted second molar Fig. 1 Buccolingual angulation BL° The buccolingual BL angulation was measured as previously described by Tolstunov et al. (19). Axial CBCT slices were used to measure the buccolingual angulation of third molars in a more horizontal position (-20◦ to 45◦, or 136◦ to 180◦). The buccolingual angulation was measured buccally or lingually from the axis bisecting the first and second molars in an axial CBCT slice (Fig. 1). The coronal CBCT slices were used for more vertically angulated teeth, and buccolingual angulation was measured with respect to the bisecting line through the second molar (from the fossa through the middle of the pulp chamber) (Fig. 1). Anterior teeth inclination AI The mandible anterior teeth were measured in relation to the mandibular plane, which was also observed in the sagittal view, we then measured the angle from the long axis of each mandible anterior teeth a vertical reference line that was perpendicular to the horizontal reference line [21] Fig. 1 Tooth Size MDW The mesiodistal width which resembles to the maximum distance across the anatomic contact point of mandibular teeth. Fig 2 segments 1 S1 The distance from distal surface of the right second molar to distal surface of right canine. segments 2 S2 The distance from distal surface of canine to mesial surface of right central incisor segments 3 S3 The distance from mesial surface of left central incisor to distal surface of left canine segments 4 S4 the distance from distal surface of canine to distal surface of the left second molar Arch length AL The vertical distance from the symphysis between two central incisors to midpoint of a line joining the disto-buccal cusp tip of the second permanent molars. Fig 2 Inter canine width I-CW measured form the cusp tip of one side to the contrary side cusp tip. Inter Premolars width I-PREM W The points on the 1st and 2nd premolar were marked from the buccal cusp tip to the buccal cusp tip of the contralateral side Inter-molar width I-MW Linear distance obtained from mesio-bucal cusp tip of right side to the left side Anterior dental crowding ADC The anterior crowding was calculated as the differences between the sum of the tow anterior segments (S2+S3) and the sum of tooth size from right to left canines. Posterior dental Crowding PDC The posterior arch crowding was calculated as the differences between the right and left posterior segments, and the tooth size parameters. Overall arch crowding OAC The overall arch crowding was measured as the sum of anterior and posterior dental crowding. Table 3 Demographic data and the descriptive statistics of the measured variables Data Study group Control group Patients (N) 100 20 Gender Male 43 8 Female 57 12 Variable Mean SD Mean SD M3M Angulation Buccolingual inclination 19.83 20.25 7.63 3.54 Mesiodistal angulation 54.07 5.88 2.69 1.41 Anteroposterior parameters Anterior teeth inclination 21.22 1.61 22.78 7.53 Anterior crowding 3.01 0.92 2.23 1.43 Posterior crowding 0.80 1.87 0.75 0.69 Overall arch crowding 3.82 2.47 2.83 1.56 Arch length 39.29 1.72 36.93 2.13 Transvers parameters Inter-canine width 26.79 2.14 26.05 1.53 Inter 1 st premolar width 35.44 2.85 35.18 2.10 Inter 2 nd premolar width 41.10 3.11 41.33 2.36 Inter 1 st molar width 46.31 3.16 46.19 2.72 Inter 2 nd molar width 53.17 2.25 53.00 2.08 Table 5 Analysis of variance (ANOVA) and Tukey tests for dental arch parameters and M3M MD° groups One way ANOVA Post hoc test M3M MD ° G1 (MD ° 10-45°) G2 (MD ° ﹥ 45°) (G3) less-10°control P-value G1 vs G2 G1 vs G3 G2 vs G3 Anteroposterior parameters Variables Mean SD Mean SD Mean SD P-value Anterior crowding 2.57 1.47 3.17 0.14 2.24 1.43 *0.02 0.14 0.69 *0.04 Posterior crowding 1.05 1.06 0.67 0.80 0.71 0.69 0.11 0.91 0.45 0.09 Overall arch crowding 3.75 2.03 3.86 1.79 2.83 1.56 0.09 0.95 0.17 0.07 Anterior teeth inclination 21.99 5.66 20.79 2.17 22.78 7.53 0.38 0.62 0.89 0.42 Arch length 38.87 2.38 39.34 0.56 36.93 2.13 *** 0.57 ** *** Transvers parameters Inter-canine width 26.92 1.47 26.73 1.86 26.07 1.50 0.32 0.90 0.18 0.26 Inter 1 st premolar width 35.54 1.81 35.38 2.31 35.21) 2.10 0.94 0.93 0.81 0.92 Inter 2 nd premolar width 40.95 3.05 41.14 2.79 41.43 2.32 0.88 0.98 0.92 0.96 Inter 1 st molar width 45.89 2.78 46.59 3.29 46.04 2.66 0.60 0.44 0.89 0.86 Inter 2 nd molar width 52.24 3.25 53.69 3.03 52.94 2.16 0.11 0.05 0.63 0.63 * P < 0.05 ** P < 0.01 *** P < 0.001 Table 4 and 6 are available in the Supplementary Files section. Table 7 is not available with this version Additional Declarations No competing interests reported. Supplementary Files Supplementarymaterial.docx Table4.docx Table6.docx Cite Share Download PDF Status: Published Journal Publication published 15 May, 2023 Read the published version in Clinical Oral Investigations → Version 1 posted Editorial decision: Major revision 28 Feb, 2023 Reviews received at journal 20 Feb, 2023 Reviewers agreed at journal 11 Feb, 2023 Reviewers agreed at journal 29 Dec, 2022 Reviewers invited by journal 22 Dec, 2022 Editor assigned by journal 12 Dec, 2022 Submission checks completed at journal 12 Dec, 2022 First submitted to journal 10 Dec, 2022 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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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-2365433","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":159278643,"identity":"a397737a-46a4-4dfb-b5d1-dc72dd5879f6","order_by":0,"name":"Ohood Haider","email":"","orcid":"","institution":"Second Xiangya Hospital of Central South University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ohood","middleName":"","lastName":"Haider","suffix":""},{"id":159278644,"identity":"080caa62-fa4f-406f-8dda-576ab64691ab","order_by":1,"name":"Mufeed A. Sharaf","email":"","orcid":"","institution":"Zhejiang University Medical College Affiliated Stomatological Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Mufeed","middleName":"A.","lastName":"Sharaf","suffix":""},{"id":159278645,"identity":"105a7a7e-d4d6-49de-98e7-10252f817579","order_by":2,"name":"Abbas Ahmed Abdulqader","email":"","orcid":"","institution":"West China Hospital of Sichuan University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Abbas","middleName":"Ahmed","lastName":"Abdulqader","suffix":""},{"id":159278646,"identity":"1c74b7d9-e968-4d6d-8b20-80f8487b13fc","order_by":3,"name":"Najah Alhashimi","email":"","orcid":"","institution":"Unit and Divisional Chief Orthodontics at Hamad Medical Corporation, Qatar University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Najah","middleName":"","lastName":"Alhashimi","suffix":""},{"id":159278647,"identity":"944cfd79-b932-491e-bc77-b78992249870","order_by":4,"name":"Hassan Sherrhan","email":"","orcid":"","institution":"Lanzhou University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hassan","middleName":"","lastName":"Sherrhan","suffix":""},{"id":159278648,"identity":"ae174c5d-4f61-429d-a7ca-490a239bd6f0","order_by":5,"name":"Chen Chen","email":"","orcid":"","institution":"Second Xiangya Hospital of Central South University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Chen","middleName":"","lastName":"Chen","suffix":""},{"id":159278650,"identity":"1ae4292d-67b7-4eb1-b392-ffa0e93dd082","order_by":6,"name":"Waleed Alsoufi","email":"","orcid":"","institution":"Second Xiangya Hospital of Central South University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Waleed","middleName":"","lastName":"Alsoufi","suffix":""},{"id":159278651,"identity":"bdba367f-f091-4c55-b744-549bdfd0caf5","order_by":7,"name":"Zeng Yun Ting","email":"","orcid":"","institution":"Second Xiangya Hospital of Central South University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Zeng","middleName":"Yun","lastName":"Ting","suffix":""},{"id":159278652,"identity":"1903d81e-3bff-456f-b49a-3b5cafe8865c","order_by":8,"name":"Xiao Li Wei","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAz0lEQVRIiWNgGAWjYDACZhBRwCAH4bERrcWAwZgELQwQLYkNRGsxOM788AGDweH0/v4zBgwfyg4z8M9uwK9FspnN2ACoJXfGjRwDxhnnDjNI3DmAXws/M4OZBIPB7dwNEjwGzLxthxkMJBLwa2FjZv8G0pJuwH/GgPkvMVr4mXnAtiQYMOQYMDMSo0WymacY6Jf/hjNupBUc7DmXziNxg4AWg/PHNz5gqEiT5+8/vPHBjzJrOf4ZBLSAAPMfKOMAEPMQVj8KRsEoGAWjgCAAACQNOMuQSiPRAAAAAElFTkSuQmCC","orcid":"","institution":"Second Xiangya Hospital of Central South University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Xiao","middleName":"Li","lastName":"Wei","suffix":""},{"id":159278653,"identity":"32fc4327-65a6-4557-9356-63f2f88b89e4","order_by":9,"name":"Maged S. Alhammadi","email":"","orcid":"","institution":"Jazan University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Maged","middleName":"S.","lastName":"Alhammadi","suffix":""}],"badges":[],"createdAt":"2022-12-10 20:44:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2365433/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2365433/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00784-023-05047-6","type":"published","date":"2023-05-15T20:52:52+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":30329358,"identity":"1df404e7-4bb8-46a3-b0c7-11a63e4285cc","added_by":"auto","created_at":"2022-12-14 16:07:56","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1284373,"visible":true,"origin":"","legend":"\u003cp\u003eThe three-dimensional measurement of the mandibular third molar angulation and the mandibular incisors inclination: A) The mesiodistal angulation measuring the long axis of the tooth relative to the vertical axis through the erupted the second molar angle of the impacted or erupted M3M , B) The buccolingual angulation of horizontally positioned M3M was measured buccally or lingually from the axis bisecting the first and second molars in an axial CBCT slice, C) The buccolingual angulation of more vertically M3M was measured with respect to the bisecting line through the second molar, D) The mandibular incisors were measured in relation to the mandibular plane, which was also observed in the sagittal view.\u003c/p\u003e","description":"","filename":"Fig1TIFF.png","url":"https://assets-eu.researchsquare.com/files/rs-2365433/v1/e966bba00a1ce679ba4201c1.png"},{"id":30329362,"identity":"ea097a9f-3550-4f1b-a13b-29c3099ece5a","added_by":"auto","created_at":"2022-12-14 16:07:57","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":6521953,"visible":true,"origin":"","legend":"\u003cp\u003eThe dental arch measurements: A) The right side represent segment (S1) from distal second molar to distal canine, the anterior segment (S2) from distal canine to mesial central incisor that were calculated bilaterally. The left side represent tooth size measurements from mesial, B) The distance from the midpoint of the symphysis between the central incisors to the line that links the disto-buccal cusp tips of the right and left second molars, C) The Inter canines, premolars, and molars width; the distance from buccal cusps of the teeth on right side to those on left side.\u003c/p\u003e","description":"","filename":"Fig2TIFF.png","url":"https://assets-eu.researchsquare.com/files/rs-2365433/v1/692ed75e9640066f427f46bd.png"},{"id":44729130,"identity":"9f88d605-5574-4657-b0f2-57e516541e91","added_by":"auto","created_at":"2023-10-16 21:13:36","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2550493,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2365433/v1/1ed493e3-7a12-4df0-ac78-65da491e50ea.pdf"},{"id":30329359,"identity":"6bbe4019-7a30-4b04-a1f9-17be872e0745","added_by":"auto","created_at":"2022-12-14 16:07:56","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":19567,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-2365433/v1/042bebc10e94f1d39a817ec9.docx"},{"id":30331877,"identity":"a54a46ee-2050-48d3-8070-b7e90ed360c1","added_by":"auto","created_at":"2022-12-14 16:23:56","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":31727,"visible":true,"origin":"","legend":"","description":"","filename":"Table4.docx","url":"https://assets-eu.researchsquare.com/files/rs-2365433/v1/1a42d02a80e4adbdffdb971d.docx"},{"id":30330990,"identity":"f4bec236-b972-41bf-ad34-53020d88eb8d","added_by":"auto","created_at":"2022-12-14 16:15:56","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":25084,"visible":true,"origin":"","legend":"","description":"","filename":"Table6.docx","url":"https://assets-eu.researchsquare.com/files/rs-2365433/v1/c60dc6daab92668df751f891.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Three-dimensional relationship between the degree of bilateral impacted mandibular third molars angulation and the mandibular dental arch parameters: a cross-sectional comparative study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTooth eruption is considered to be a complex process; hence, tooth eruption can occur early, late, or even fail most of the time when the eruption of the tooth exceeds the scheduled time[\u003ca href=\"#_ENREF_1\" title=\"Alhammadi, 2018 #1994\"\u003e1\u003c/a\u003e]. Third molar is the most commonly impacted tooth. The recorded frequency of its impaction varied greatly between populations, with the highest recorded in a Singapore Chinese population at 68.6%[\u003ca href=\"#_ENREF_2\" title=\"Quek, 2003 #1996\"\u003e2\u003c/a\u003e]. They are commonly in the mandible than maxillary arch, and females have a higher prevalence than males[\u003ca href=\"#_ENREF_3\" title=\"Panda, 2018/09/01 #1997\"\u003e3\u003c/a\u003e]. The correlation between mandibular incisor crowding and third molar has been a controversial issue for a long time in dentistry literature\u0026nbsp;[\u003ca href=\"#_ENREF_4\" title=\"Proffit, 1986 #1998\"\u003e4\u003c/a\u003e]\u0026nbsp;. The most debated question is whether third molar impaction played a role in the development or recurrence of malocclusion. Despite the discussion of this topic take a place in literature , however the question of whether impacted third molar teeth contribute to anterior dental arch crowding remains unanswered, particularly when three-dimensional imaging modalities are used[\u003ca href=\"#_ENREF_5\" title=\"Zawawi, 2014 #1999\"\u003e5\u003c/a\u003e].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePanoramic radiography (PR) has been used as a diagnostic tool. However, because of this modality\u0026apos;s two-dimensional nature, there are overlaps of anatomical regions that are important for making decisions, which increases the chance of error. Cone-beam computed tomography (CBCT) has enabled the generation of trans-sections (i.e., perpendicular to the tangent of the dental arch) and three-dimensional reconstructions from digital images in the axial, coronal, and sagittal dimensions. Its ability to capture the third dimension, the depth of the image and the lack of overlap between nearby anatomical components is what makes it unique[\u003ca href=\"#_ENREF_6\" title=\"Jaroń, 2021 #2001\"\u003e6\u003c/a\u003e]. CBCT enables us to determine tooth size and arch dimension as rapidly, reliably, correctly, and reproducibly as measurements obtained by the digital method on digitalized plaster models[\u003ca href=\"#_ENREF_7\" title=\"Alam, 2014 #2002\"\u003e7\u003c/a\u003e,\u0026nbsp;\u003ca href=\"#_ENREF_8\" title=\"Al-Mashraqi, 2021 #2003\"\u003e8\u003c/a\u003e].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA number of factors contribute to late incisor crowding. The eruption of the lower third molars is regarded as the most important etiologic factor, followed by others such as tooth size, dental arch shape, retroclination of the lower incisors, skeletal and soft tissue growth changes, mesial movement of the posterior teeth, mandibular arch length and width, jaw-to-size ratio, mandibular growth pattern, \u0026nbsp;gender, forces from periodontal fibers, and natural aging\u0026nbsp;[\u003ca href=\"#_ENREF_9\" title=\"Karasawa, 2013 #2004\"\u003e9-12\u003c/a\u003e].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNiedzielska et al. came to the conclusion that inadequate retromolar space exacerbates malocclusion and dental crowding of lower anterior teeth, which is produced by the eruption of the third molar, indicating the significance of removing the third molar\u0026nbsp;[\u003ca href=\"#_ENREF_13\" title=\"Niedzielska, 2005 #2011\"\u003e13\u003c/a\u003e]. Lindauer et al. concluded that the mandibular molars are expected to be a cause of dental crowding by American orthodontists and oral and maxillofacial surgeons, and they recommended their removal[\u003ca href=\"#_ENREF_14\" title=\"Lindauer, 2007 #2012\"\u003e14\u003c/a\u003e]. According to a study by Seerab Husain utilising CBCT, there is a positive link between the crowding of the mandibular incisors and third molars, indicating that third molars are one of the etiological causes for crowding, if not the sole one[\u003ca href=\"#_ENREF_15\" title=\"Husain, 2021 #2013\"\u003e15\u003c/a\u003e]. On the other hand, Sidlauskas and Trakiniene evaluated 91 people with an average age of 21. In their study, crowding was assessed by comparing the mesiodistal widths of the individuals\u0026apos; teeth to the length of the corresponding segment of the mandibular dental arch. The authors did not report significant differences in mandibular dental arch crowding between the groups with erupted, unerupted, and agenesis of third molars. They came to the conclusion that third molars and late lower dental arch crowding are not related[\u003ca href=\"#_ENREF_16\" title=\"Sidlauskas, 2006 #2014\"\u003e16\u003c/a\u003e]. Harradine et al. reported similar results in orthodontic treatment subjects. In a randomized controlled study, they investigated the influence of third molar extraction on the development of the crowding in anterior mandibular segment. The results reveal a negligible difference between the groups (third molars extracted versus non-extracted) that is not statistically significant. Therefore, they concluded that the extraction of third molars to avoid or minimize late incisor crowding was not justifiable[\u003ca href=\"#_ENREF_11\" title=\"Harradine, 1998 #2006\"\u003e11\u003c/a\u003e].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eEven though a recently published systematic review reported that only 6 studies were selected in the quantitative synthesis and none of these studies used CBCT for evaluation of such 3D problem[\u003ca href=\"#_ENREF_17\" title=\"Assali, 2022 #2015\"\u003e17\u003c/a\u003e]. Thus, there is a great inconsistency in studies regarding to the relationship of IM3M and other dental arch parameters like anterior crowding, at the same time using more reliable diagnostic tool like 3D CBCT to add well designed study with comprehensive three-dimensional measurements to the existing literature. This study aimed to three-dimensionally evaluate the relationship between the degree of bilateral impacted mandibular third molars (IM3M) angulation and the mandibular dental arch parameters in normal skeletal and dental malocclusion patients.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and participants:\u003c/h2\u003e \u003cp\u003eThis study was designed as a retrospective cross-sectional comparative study that was carried out at the stomatology hospital, central south University, China. Patients must consent to participate in any trial and approve the use of their data, according to the institution\u0026rsquo;s policy, which includes a thorough description of the procedure\u0026rsquo;s advantages and risks. This study was approved by the committee of ethical and clinical scientific research at the hospital of stomatology, Central South University, China, (LYF2022130).\u003c/p\u003e \u003cp\u003eThis study included the patients who had undergone cone-beam computed tomography CBCT in the Second Xiangya Hospital of Central South University from 2019 to 2021. The inclusion criteria included the following: 1) age 20\u0026ndash;30 years old, 2) skeletal Class I according to the Chinese norms; ANB\u0026thinsp;=\u0026thinsp;2.7\u0026deg; \u0026plusmn; 2.0\u0026deg;[18] and dental (canine/molar) Class I relationship, 3) complete permanent dentition, 4) lower third molar with completely formed roots, 5) reported healthy periodontium based on the recorded clinical records, and 6) high-quality CBCT volumetric data. While the exclusion criteria included: 1) missing or extra teeth, 2) abnormal tooth size and morphology, 3) previous orthodontic-surgical treatment, 4) incompletely formed roots, unilateral impacted or erupted M3M, 5) interproximal caries and dental restoration, crown and bridge, 6) noticeable alveolar bone loss, and 7) cleft lip and/ or palate. The control group cases characterized by fully formed and erupted bilateral M3M in normal or near normal eruption, buccolingual angulations less 12\u0026deg;, and mesiodistal angulation less 10\u0026deg;.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eStudy sample size:\u003c/h2\u003e \u003cp\u003eG*power 3.0.10 software was used to determine the sample size with an alpha value of 0.05 and a power of 95% based on the study conducted by Hasegawa et al.[19], who reported Little\u0026rsquo;s index of irregularity of 1.66\u0026thinsp;\u0026plusmn;\u0026thinsp;0.83 mm and 4.08\u0026thinsp;\u0026plusmn;\u0026thinsp;1.61 mm in the normal and crowded subjects in their study aimed to ascertain whether the lower third molar can affect anterior crowding and/or the inclination of teeth in the lower lateral segments.. Power analysis showed a minimum sample of 18 subjects is to be included. However, the sample size was increased to a minimum 20 subjects for each study group.\u003c/p\u003e \u003cp\u003eOne hundred twenty young adult patients\u0026rsquo; with well documented clinical and radiographic data fulfilled the selection criteria. The participants were divided into study group (N\u0026thinsp;=\u0026thinsp;100): who have bilateral impacted M3M, the study group was further divided into three subgroups according to buccolingual inclination of the IM3M; Group A\u0026thinsp;\u0026lt;\u0026thinsp;12\u0026deg; on the center of the ridge(N\u0026thinsp;=\u0026thinsp;30), Group B (12\u0026deg;-24\u0026deg;) off-center of the ridge(N\u0026thinsp;=\u0026thinsp;40), and Group C\u0026thinsp;\u0026gt;\u0026thinsp;24\u0026deg; off center of the ridge (N\u0026thinsp;=\u0026thinsp;30).and control group (N\u0026thinsp;=\u0026thinsp;20) with normal and fully erupted bilateral M3M. The control group included the participants who have bilateral eruption (E) M3M with buccolingual inclination less than 12\u0026deg;, mesiodistal angulations less than 10\u0026deg; in normal eruption[20].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eThree-dimensional imaging:\u003c/h2\u003e \u003cp\u003eThe following parameters were used for all CBCT imaging on an i-CAT instrument (imaging Sciences International Inc., Hatfield, PA, USA): Voxel size: 0.3 mm, Field of View (FOV): 16.0 cm 13.0 cm, Voltage: 120 kVp, Filament Current: 18.54 mAs, Total Scan Time: 8.9 s. Patients were told not to swallow while being scanned, and their heads were held in a conventional position with their teeth with maximal teeth intercuspation, the horizontal plane (HP) parallel to the ground. Digital Imaging and Communications in Medicine (DICOM) files were acquired and then imported into Invivo Anatomage version 6 software (Anatomage, San Diego, CA, United States) for 3D analysis.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eOutcomes assessment:\u003c/h2\u003e \u003cp\u003eThe coordinate system's orientation is defined based on the face skeletal midline points of the Nasion (N), Anterior Nasal Spine (ANS), and Sella in order to acquire consistent alignment of the 3D images (S). The right Orbital (Or) point and two Porion (Pr) points serve as the lateral landmarks. Then, depending on the most obvious sites, the three-dimensional landmarks were digitally created. The skeletal reference line and measurements are presented in Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the three-dimensional measurements of angulations of impacted (I) and eruption (E) third molar (IM3M) and dental arch parameters. Selected points in the three planes (sagittal, axial and coronal,) were individually adjusted using a slice locator. Angulations of third molar[21] and dental arch parameters[7] and inclination of anterior teeth[22] used in this study are presented in [Figures 1 and 2]. After grouping the study group into three sub-groups (GA, GB, and GC) according to the M3M buccolingual inclination, the means of dental arch anteroposterior and transverse parameters were compared with each other and with those in the control group. The M3M mesiodistal angulation was further divided into three groups according to the degree of angulation; Group 1 (MD\u0026deg;10\u0026ndash;45\u0026deg;); Group 2(MD\u0026deg;๥45\u0026deg;) and Group 3 (control) less 10\u0026deg;[23]. Dental arch anteroposterior and transvers parameters were compared between mesiodistal groups. All parameters were statistically analyzed to determine the relationship between buccolingual and mesiodistal angulations of impacted and erupted M3M with the anteroposterior and transvers arch parameters. The definitions of skeletal and dental measurements are presented in Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using SPSS 26.0 (software (IBM Corp., Armonk, NY, USA). Continuous variables are expressed as a number of observations, mean and standard deviation. Categorical and discrete variables were presented by frequency and percentage. The Shapiro-Wilk test was used to test the normal distribution. The means of anteroposterior and transfer arch parameters were compared in both buccolingual M3M and mesiodistal M3M groups using One-way analysis of variance (ANOVA) followed by Tukey post hoc test to compare the mean values between the groups. The Pearson's correlation test was used to confirm the correlation between IM3M buccolingual and mesiodistal angulations and the anteroposterior and transfer arch parameters. Intra- and inter-class correlations were calculated to assess the reliability and reproducibility of the parameters. The P-value was set at 0.05 for significant differences.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eBoth inter-observer and intra-observer reliability were excellent; detailed data are presented in supplementary material 1. The demographic data as well as the descriptive statistics presented in Table \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eRegarding the M3M buccolingual angulations and anteroposterior parameters, One-way ANOVA revealed highly significant differences between the M3M BL\u0026deg; angulation and anterior teeth inclination (P\u0026thinsp;\u0026lt;\u0026thinsp;.001), arch length (P\u0026thinsp;\u0026lt;\u0026thinsp;.01), and inter 2nd MW (P\u0026thinsp;\u0026lt;\u0026thinsp;.001) as shown in Table \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The inter-group compressions revealed a significant difference in anterior teeth inclination between Group A and Group C, increased 7.2\u0026deg; in group C (P\u0026thinsp;\u0026lt;\u0026thinsp;.001), Group A and Group D, increased 5.1\u0026deg; in group D (P\u0026thinsp;\u0026lt;\u0026thinsp;.05), and Group B and Group C, increased 3.8\u0026deg; in group C (P\u0026thinsp;\u0026lt;\u0026thinsp;.05). Statistically significant difference was founded in arch length between Group A and Group D (P\u0026thinsp;\u0026lt;\u0026thinsp;.01), Group B and Group D (P\u0026thinsp;\u0026lt;\u0026thinsp;.01), and Group C and Group D (P\u0026thinsp;\u0026lt;\u0026thinsp;.05).\u003c/p\u003e \u003cp\u003eFor the M3M buccolingual angulation and transvers parameters, the difference in inter 2nd MW was statistically significant difference between Group A and Group B (P\u0026thinsp;\u0026lt;\u0026thinsp;.01), Group A and Group C (P\u0026thinsp;\u0026lt;\u0026thinsp;.001) Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe results of the M3M mesiodistal angulation and dental arch parameters, within group comparison have showed a statistically significant difference in arch length measurement (P\u0026thinsp;\u0026lt;\u0026thinsp;.001) table. Between group comparison has revealed a statistically significant difference in anterior teeth crowding between Group 2 and Group 3, increased 0.93 mm in group2 (P\u0026thinsp;\u0026lt;\u0026thinsp;.001), as well as, in arch length between Group 1 and Group 3, increased 1.9 mm in group1 (P\u0026thinsp;\u0026lt;\u0026thinsp;.001), and Group 2 and Group 3, increased 2.42 mm in group2 (P\u0026thinsp;\u0026lt;\u0026thinsp;.001). However, there is no significant difference between M3M MD\u0026deg; and transvers arch parameters (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe correlation between IM3M BL\u0026deg; and dental arch parameters was calculated in Table \u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. Significant positive correlation was founded between IM3M BL\u0026deg; and anterior teeth inclination (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.05), which means that the increase in degree of IMEM angulation lingually is associated with increasing of degree of anterior teeth buccal inclination. However significant negative correlation was founded between inter 1st MW, inter 2nd MW (P\u0026thinsp;\u0026lt;\u0026thinsp;.05 and P\u0026thinsp;\u0026lt;\u0026thinsp;.01, respectively). Interpretation normally\u003c/p\u003e \u003cp\u003eFor Correlation between IM3M MD\u0026deg; and dental arch parameters, significant positive correlation was founded between IM3M MD\u0026deg; and anterior teeth crowding (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.01), arch length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.01), inter 2nd MW \u003cem\u003e(P\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.05). It means that the increase in the degree of IM3M mesiodistal angulation is associated with increasing in anterior teeth crowding, arch length and inter 2nd MW as showed in table 7.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eCrowding in the lower anterior teeth is among the most common malocclusions that lead to the need for orthodontic treatment since it affects an individual's esthetics and oral health. At the same time, recognizing the etiological factors of crowding and relapse in mandibular anterior teeth after treatment is considered an issue facing orthodontists[10, 20, 24]. It is still unclear if the lower third tooth has a role in these issues. Regardless, studies examining the association between the lower third molar and the different dental arch parameters using three-dimensional analyses are still lacking. As a result, this study aims to use a three-dimensional analysis to assess the relationship between the different angulations of the impacted third molar (buccal, lingual, mesial, and distal) and the degree of these angles with the anteroposterior and transverse arch parameters (crowding, arch length, arch width) in a patient with skeletal class I malocclusions.\u003c/p\u003e \u003cp\u003eRichardson et al. examined the relationship between the original crowding and the changes in crowding after five years in individuals with both bilaterally impacted and erupted M3M, they concluded that the individuals with bilaterally impacted M3M tends to have more crowding of early permanent dentition, both anteriorly and posteriorly[25]. Similarly, Niedzielska et al. assessed lower incisor crowding and dental arch changes after three years in a sample with bilateral retained or extracted M3M. They found that retained M3M was associated with increased tooth crowding in relation to Ganss ratio[13].\u003c/p\u003e \u003cp\u003eOur study has examined the angulation of bilateral IM3M to analyze the relationship between the degree of that angulation and dental arch parameters. The present study found a statistically significant difference between IM3M MD \u0026deg;and anterior teeth crowding. These results confirm those reported in the previous studies that found a significant relation between bilaterally IM3M and lower anterior crowding. Furthermore, our results could support the hypothesis that the erupting third molars related to anterior teeth forward inclination and cause their crowding, as a significant difference was found between the IM3M MD\u0026deg;๥45\u0026deg; and the control group.\u003c/p\u003e \u003cp\u003eAdditionally, Pearson's correlation has supported that idea, a significant positive correlation between IM3M MD\u0026deg; anterior crowding was noticed, which means that the increasing angulation of IM3M mesially increases lower anterior teeth crowding. However, the results of the current study were contrary to those reported by Shanley et al. and Kaplan et al;[26, 27] who assessed the orthodontically untreated subjects with M3M. The previous authors didn\u0026rsquo;t find a significant difference between bilaterally impacted and erupted groups concerning the anterior teeth crowding. Although different in results between our study and the previous studies, we still agree that anterior crowding is a multifactorial phenomenon, and the effect of other factors cannot be ignored[16, 28]; the difference in results may be due to differences in population or measuring methods.\u003c/p\u003e \u003cp\u003eThe current study has observed a significant difference between IM3M buccolingual angulation and anterior teeth inclination, which means that the increase in IMEM angulation lingually increases anterior teeth labial inclination. At the same time, the angulation of IM3M lingually was significantly associated with decreasing in inter 2nd MW. This could be interpreted as the reduction in 2nd MW, maybe due to the reduced arch width in the examined samples; thus, the anterior teeth were proclined to compensate for the decrease in arch width.\u003c/p\u003e \u003cp\u003eFurthermore, our study found a significant difference in arch length parameters between both IM3M BL\u0026deg; and MD\u0026deg; groups; the increasing degree of angulation mesially/lingually was associated with decreasing arch length. However, a significant positive correlation was found only between IM3M BL\u0026deg; and arch length. These results support the hypothesis that the impaction of M3M, consequently the crowding in anterior teeth, was related to an increase in tooth size[29, 30]. This was very clear in our study, where the arch length was significantly decreased in control (EM3M) group compared with the impacted (IM3M) groups. Finally, this study recorded a significant negative correlation between inter 1st and 2nd MW and IM3M ML\u0026deg;; this correlation was absent in BL\u0026deg; groups and was identical to the previous study that hypothesis that force excreted by IM3M may cause pushing or buccal rotation of second molars.[4]\u003c/p\u003e"},{"header":"Limitations","content":"\u003cp\u003eThe sample size was one of the study's limitations. Although calculated in advance, a larger sample size is suggested, with a greater emphasis on male-female comparisons in all variables analyzed. Furthermore, we recommend more classification based on facial pattern (brachy, mesocephalic, or dolichocephalic) to assess any relationship in this regard, as mandible inclination may affect the tendency for more mesial pressure against the teeth. The ethnicity was another limitation as it was restricted to Chinese; results may differ if other ethnicities are included. In addition, the research team suggested that future studies use a mixed longitudinal design rather than a single point of observation.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe degree of IM3M BL\u0026deg; and MD\u0026deg; was associated with the changes anterior teeth crowding and inclination, arch length, and inter second molar width parameters. The increase in IM3M MD\u0026deg; angulations was associated with increase in anterior teeth crowding and inter 2nd MW.The Increasing of IM3M BL\u0026deg; inclination the increasing of anterior teeth inclination, and the decreasing of 1st MW, inter 2nd MW.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eLYF2022130\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eAvailability of data and material\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eNo\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003eContributions of author(s)\u003c/li\u003e\n \u003cli\u003eConception\u0026nbsp;and\u0026nbsp;design\u0026nbsp;of\u0026nbsp;study:\u003cu\u003e\u0026nbsp;\u0026nbsp;\u003c/u\u003e\u003cu\u003eOhood Haider\u003c/u\u003e,\u003cu\u003e\u0026nbsp;Xiao\u003c/u\u003e\u003cu\u003e\u0026nbsp;Li Wei *\u003c/u\u003e\u003cu\u003e.\u003c/u\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cul\u003e\n \u003cli\u003eAcquisition\u0026nbsp;of\u0026nbsp;data:\u003cu\u003e\u0026nbsp;\u003c/u\u003e\u003cu\u003eChen Chen, Mufeed Ahmed Sharaf, Najah Alhashimi.\u0026nbsp;\u003c/u\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eAnalysis\u0026nbsp;and/or\u0026nbsp;interpretation\u0026nbsp;of\u0026nbsp;data:\u003cu\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/u\u003e\u003cu\u003eAbbas Ahmed Abdulqader\u003c/u\u003e\u003cu\u003e, Hassan Sherrhan, Chen Chen,\u003c/u\u003e \u003cu\u003eWaleed Alsoufi\u003c/u\u003e\u003cu\u003e.\u003c/u\u003e\u003c/li\u003e\n \u003cli\u003eDrafting\u0026nbsp;the\u0026nbsp;manuscript:\u003cu\u003e\u0026nbsp;\u0026nbsp;\u003c/u\u003e\u003cu\u003eOhood Haider\u003c/u\u003e,\u003cu\u003e\u0026nbsp;Mufeed Ahmed sharaf,\u0026nbsp;\u003c/u\u003e\u003cu\u003eMaged S. Alhammadi\u003c/u\u003e\u003cu\u003e.\u003c/u\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cul\u003e\n \u003cli\u003eRevising\u0026nbsp;the\u0026nbsp;manuscript\u0026nbsp;critically\u0026nbsp;for\u0026nbsp;important\u0026nbsp;intellectual\u0026nbsp;content:\u003cu\u003e\u0026nbsp;\u003c/u\u003e\u003cu\u003eOhood Haider,\u003c/u\u003e \u003cu\u003eZeng Yun Ting, Maged S. Alhammadi, Xiao Li Wei *.\u003c/u\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThe authors would like to thank Prof. Feng Yun Zhi, Prof. Shen gao Huang and Dr. Bushra Sufyan Almaqrami for their consultations and assistance in accomplishing this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAlhammadi MS, Asiri HA and Almashraqi AA (2018) Incidence, severity and orthodontic treatment difficulty index of impacted canines in Saudi population. J Clin Exp Dent 10:e327-e334. doi: 10.4317/jced.54385\u003c/li\u003e\n \u003cli\u003eQuek SL, Tay CK, Tay KH, Toh SL and Lim KC (2003) Pattern of third molar impaction in a Singapore Chinese population: a retrospective radiographic survey. Int J Oral Maxillofac Surg 32:548-52.\u003c/li\u003e\n \u003cli\u003ePanda S and Sharma K (2018/09/01) Mandibular third molar impaction in different facial growth patterns. Rama Univ J Dent Sci 5:8-6.\u003c/li\u003e\n \u003cli\u003eProffit WR (1986) On the aetiology of malocclusion. The Northcroft lecture, 1985 presented to the British Society for the Study of Orthodontics, Oxford, April 18, 1985. Br J Orthod 13:1-11.\u003c/li\u003e\n \u003cli\u003eZawawi KH and Melis M (2014) The role of mandibular third molars on lower anterior teeth crowding and relapse after orthodontic treatment: a systematic review. ScientificWorldJournal 2014:615429. doi: 10.1155/2014/615429\u003c/li\u003e\n \u003cli\u003eJaroń A, Gabrysz-Trybek E, Bladowska J and Trybek G (2021) Correlation of Panoramic Radiography, Cone-Beam Computed Tomography, and Three-Dimensional Printing in the Assessment of the Spatial Location of Impacted Mandibular Third Molars. J Clin Med 10. doi: 10.3390/jcm10184189\u003c/li\u003e\n \u003cli\u003eAlam MK, Shahid F, Purmal K, Ahmad B and Khamis MFb (2014) Tooth size and Dental arch Dimension measurement through Cone beam Computed Tomography: Effect of Age and Gender. Book title.,\u003c/li\u003e\n \u003cli\u003eAl-Mashraqi AA, Alhammadi MS, Gadi AA, Altharawi RA, Zamim KAH and Halboub E (2021) Accuracy and reproducibility of permanent dentitions and dental arch measurements: comparing three different digital models with a plaster study cast. Int J Comput Dent 24:353-362.\u003c/li\u003e\n \u003cli\u003eKarasawa LH, Rossi AC, Groppo FC, Prado FB and Caria PH (2013) Cross-sectional study of correlation between mandibular incisor crowding and third molars in young Brazilians. Med Oral Patol Oral Cir Bucal 18:e505-9. doi: 10.4317/medoral.18644\u003c/li\u003e\n \u003cli\u003eAmaral MGG and L\u0026oacute;pez LVR (2018) Prevalence, types and etiologic factors of mandibular crowding in orthodontic patients in Tabasco, Mexico, 2015-2016. Revista Mexicana de Ortodoncia 6.\u003c/li\u003e\n \u003cli\u003eHarradine NW, Pearson MH and Toth B (1998) The effect of extraction of third molars on late lower incisor crowding: a randomized controlled trial. 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Am J Orthod Dentofacial Orthop 132:43-8. doi: 10.1016/j.ajodo.2005.07.026\u003c/li\u003e\n \u003cli\u003eHusain S and Rengalakshmi S (2021) Correlation between mandibular third molar and mandibular incisor crowding: A retrospective CBCT-based study. J Dent Res Dent Clin Dent Prospects 15:247-250. doi: 10.34172/joddd.2021.040\u003c/li\u003e\n \u003cli\u003eSidlauskas A and Trakiniene G (2006) Effect of the lower third molars on the lower dental arch crowding. Stomatologija 8:80-4.\u003c/li\u003e\n \u003cli\u003eAssali A, Oualalou Y and Zaoui FZ (2022) Evolution of Third Molars in Orthodontics: What about Anterior Dental Crowding? - A Systematic Review. Integrative Journal of Medical Sciences.\u003c/li\u003e\n \u003cli\u003eFeng F, Liu Y, Chi J, Wang Y, Xing B, Wang Y and Liu W (2018) Effects of anterior tooth crown inclination on occlusal relationship-A study in three-dimensional reconstruction. Arch Oral Biol 94:48-53. doi: 10.1016/j.archoralbio.2018.06.015\u003c/li\u003e\n \u003cli\u003eHasegawa Y, Terada K, Kageyama I, Tsuchimochi T, Ishikawa F and Nakahara S (2013) Influence of third molar space on angulation and dental arch crowding. Odontology 101:22-8. doi: 10.1007/s10266-012-0065-2\u003c/li\u003e\n \u003cli\u003eYitschaky O, Neuhof MS, Yitschaky M and Zini A (2016) Relationship between dental crowding and mandibular incisor proclination during orthodontic treatment without extraction of permanent mandibular teeth. Angle Orthod 86:727-33. doi: 10.2319/080815-536.1\u003c/li\u003e\n \u003cli\u003eTolstunov L, Brickeen M, Kamanin V, Susarla SM and Selvi F (2016) Is the angulation of mandibular third molars associated with the thickness of lingual bone? Br J Oral Maxillofac Surg 54:914-919. doi: 10.1016/j.bjoms.2016.06.005\u003c/li\u003e\n \u003cli\u003eSendyk M, de Paiva JB, Abr\u0026atilde;o J and Rino Neto J (2017) Correlation between buccolingual tooth inclination and alveolar bone thickness in subjects with Class III dentofacial deformities. Am J Orthod Dentofacial Orthop 152:66-79. doi: 10.1016/j.ajodo.2016.12.014\u003c/li\u003e\n \u003cli\u003eTong H, Kwon D, Shi J, Sakai N, Enciso R and Sameshima GT (2012) Mesiodistal angulation and faciolingual inclination of each whole tooth in 3-dimensional space in patients with near-normal occlusion. Am J Orthod Dentofacial Orthop 141:604-17. doi: 10.1016/j.ajodo.2011.12.018\u003c/li\u003e\n \u003cli\u003eNgan P, Alkire RG and Fields H, Jr. (1999) Management of space problems in the primary and mixed dentitions. J Am Dent Assoc 130:1330-9. doi: 10.14219/jada.archive.1999.0403\u003c/li\u003e\n \u003cli\u003eRichardson ME (1982) Late lower arch crowding in relation to primary crowding. Angle Orthod 52:300-12. doi: 10.1043/0003-3219(1982)052\u0026lt;0300:Llacir\u0026gt;2.0.Co;2\u003c/li\u003e\n \u003cli\u003eKaplan RG (1974) Mandibular third molars and postretention crowding. Am J Orthod 66:411-30. doi: 10.1016/0002-9416(74)90050-5\u003c/li\u003e\n \u003cli\u003eS SL (1962) The influence of mandibular third molar on mandibular anterior teeth. Am J Orthod 48:786-787.\u003c/li\u003e\n \u003cli\u003eMohammad RJ (2021) The Relationship of Mandibular Wisdom Tooth Within the Crowding of Lower Anterior Teeth- A Literature Review. Journal of Research in Medical and Dental Science 9:160-165.\u003c/li\u003e\n \u003cli\u003eBishara SE, Jakobsen JR, Treder JE and Stasi MJ (1989) Changes in the maxillary and mandibular tooth size-arch length relationship from early adolescence to early adulthood. A longitudinal study. Am J Orthod Dentofacial Orthop 95:46-59. doi: 10.1016/0889-5406(89)90135-2\u003c/li\u003e\n \u003cli\u003eBishara SE, Treder JE, Damon P and Olsen M (1996) Changes in the dental arches and dentition between 25 and 45 years of age. Angle Orthod 66:417-22. doi: 10.1043/0003-3219(1996)066\u0026lt;0417:Citdaa\u0026gt;2.3.Co;2\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 Definitions of skeletal references and measurements used in the study\u003c/p\u003e\n\u003ctable align=\"\" border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"751\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"17.70972037283622%\"\u003e\n \u003cp\u003e\u003cstrong\u003eSkeletal Measurements\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"15.978695073235686%\"\u003e\n \u003cp\u003e\u003cstrong\u003eAbb.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"66.3115845539281%\"\u003e\n \u003cp\u003e\u003cstrong\u003eDefinition\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"17.70972037283622%\"\u003e\n \u003cp\u003eHorizontal plane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.978695073235686%\"\u003e\n \u003cp\u003eHP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"66.3115845539281%\"\u003e\n \u003cp\u003eA plane defined by three landmarks: right Orbitale and Porion and left Porion\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.70972037283622%\"\u003e\n \u003cp\u003eMid-sagittal plane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.978695073235686%\"\u003e\n \u003cp\u003eMSP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"66.3115845539281%\"\u003e\n \u003cp\u003eA plane through Sella and Nasion and perpendicular to the horizontal plane.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.70972037283622%\"\u003e\n \u003cp\u003eVertical plane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.978695073235686%\"\u003e\n \u003cp\u003eVP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"66.3115845539281%\"\u003e\n \u003cp\u003eA plane through Sella and perpendicular to the horizontal plane and midsagittal plane.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.70972037283622%\"\u003e\n \u003cp\u003eS\u0026ndash;N plane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.978695073235686%\"\u003e\n \u003cp\u003eS-N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"66.3115845539281%\"\u003e\n \u003cp\u003eA plane constructed by two-points Sella, Nasion, and perpendicular on the horizontal plane.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.70972037283622%\"\u003e\n \u003cp\u003eMandibular plane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.978695073235686%\"\u003e\n \u003cp\u003eMP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"66.3115845539281%\"\u003e\n \u003cp\u003eA plane constructed by three-point two sides Gonion and Gnathion.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.70972037283622%\"\u003e\n \u003cp\u003eANB angle\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.978695073235686%\"\u003e\n \u003cp\u003eANB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"66.3115845539281%\"\u003e\n \u003cp\u003eThe angle between three-point landmarks (A point, Nasion, and B point).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.70972037283622%\"\u003e\n \u003cp\u003eMandibular plane angle\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.978695073235686%\"\u003e\n \u003cp\u003eGO-GN/SN\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"66.3115845539281%\"\u003e\n \u003cp\u003eThe angle between S\u0026ndash;N plane and GO-GN plane.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTable 2 Definitions of dental measurements used in the study\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003e\u003cstrong\u003eLinear measurement\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003e\u003cstrong\u003eAbb\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003e\u003cstrong\u003eDefinition\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eMesiodistal angle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eMD\u0026deg;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe sagittal CBCT slice was used to calculate the mesiodistal angle of the impacted or erupted M3M by measuring the long axis of the third molar relative to the vertical axis through the erupted second molar Fig. 1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eBuccolingual \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; angulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eBL\u0026deg;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe buccolingual BL angulation was measured as previously described by Tolstunov et al. (19). Axial CBCT slices were used to measure the buccolingual angulation of third molars in a more horizontal position (-20◦ to 45◦, or 136◦ to 180◦). The buccolingual angulation was measured buccally or lingually from the axis bisecting the first and second molars in an axial CBCT slice (Fig. 1). \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; The coronal CBCT slices were used for more vertically angulated teeth, and buccolingual angulation was measured with respect to the bisecting line through the second molar (from the fossa through the middle of the pulp chamber) (Fig. 1).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eAnterior teeth inclination\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eAI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe mandible anterior teeth were measured in relation to the mandibular plane, which was also observed in the sagittal view, we then measured the angle from the long axis of each mandible anterior teeth a vertical reference line that was perpendicular to the horizontal reference line [21] Fig. 1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eTooth Size\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eMDW\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe mesiodistal width which resembles to the maximum distance across the anatomic contact point of mandibular teeth. Fig 2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003esegments 1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eS1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe distance from distal surface of the right second molar to distal surface of right canine.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003esegments 2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eS2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003e\u0026nbsp;The distance from distal surface of canine to mesial surface of right central incisor\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003esegments 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eS3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003e\u0026nbsp;The distance from mesial surface of left central incisor to distal surface of left canine\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003esegments 4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eS4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003e\u0026nbsp;the distance from distal surface of canine to distal surface of the left second molar\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eArch length\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eAL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe vertical distance from the symphysis between two central incisors to midpoint of a line joining the disto-buccal cusp tip of the second permanent molars. Fig 2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eInter canine width \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eI-CW\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003emeasured form the cusp tip of one side to the contrary side cusp tip.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eInter Premolars\u0026nbsp;width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eI-PREM W\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe points on the 1st and 2nd premolar were marked from the buccal cusp tip to the buccal cusp tip of the contralateral side\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eInter-molar width\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eI-MW\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003eLinear distance obtained from mesio-bucal cusp tip of right side to the left side\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eAnterior dental crowding\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eADC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe anterior crowding was calculated as the differences between the sum of the tow anterior segments (S2+S3) and the sum of tooth size from right to left canines.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003ePosterior dental Crowding\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003ePDC\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe posterior arch crowding was calculated as the differences between the right and left posterior segments, and the tooth size parameters.\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.577656675749319%\"\u003e\n \u003cp\u003eOverall arch crowding\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.899182561307901%\"\u003e\n \u003cp\u003eOAC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"74.52316076294278%\"\u003e\n \u003cp\u003eThe overall arch crowding was measured as the sum of anterior and posterior dental crowding.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 3 Demographic data and the descriptive statistics of the measured variables\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"575\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003e\u003cstrong\u003eData\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" width=\"31.304347826086957%\"\u003e\n \u003cp\u003e\u003cstrong\u003eStudy group\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"36.17391304347826%\"\u003e\n \u003cp\u003e\u003cstrong\u003eControl group\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003e\u003cstrong\u003ePatients (N)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" width=\"31.304347826086957%\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"36.17391304347826%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\" width=\"100%\"\u003e\n \u003cp\u003e\u003cstrong\u003eGender\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eMale\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" width=\"31.304347826086957%\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"36.17391304347826%\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" width=\"31.304347826086957%\"\u003e\n \u003cp\u003e57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"36.17391304347826%\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"14.782608695652174%\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.52173913043478%\"\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\" width=\"100%\"\u003e\n \u003cp\u003e\u003cstrong\u003eM3M Angulation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eBuccolingual inclination\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"14.782608695652174%\"\u003e\n \u003cp\u003e19.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.52173913043478%\"\u003e\n \u003cp\u003e20.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e7.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e3.54\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eMesiodistal angulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"14.782608695652174%\"\u003e\n \u003cp\u003e54.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.52173913043478%\"\u003e\n \u003cp\u003e5.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e2.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e1.41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\" width=\"100%\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnteroposterior parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eAnterior teeth inclination\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e21.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e1.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e22.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e7.53\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eAnterior crowding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e3.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e2.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e1.43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003ePosterior crowding\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e0.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e1.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e0.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e0.69\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003e\u0026nbsp;Overall arch crowding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e3.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e2.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e2.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e1.56\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eArch length\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e39.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e1.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e36.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e2.13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\" width=\"100%\"\u003e\n \u003cp\u003e\u003cstrong\u003eTransvers parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eInter-canine width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e26.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e2.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e26.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e1.53\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eInter 1\u003csup\u003est\u003c/sup\u003epremolar width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e35.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e2.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e35.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e2.10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eInter 2\u003csup\u003end\u003c/sup\u003epremolar width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e41.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e3.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e41.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e2.36\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eInter 1\u003csup\u003est\u003c/sup\u003emolar width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e46.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e3.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e46.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e2.72\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"32.52173913043478%\"\u003e\n \u003cp\u003eInter 2\u003csup\u003end\u003c/sup\u003emolar width\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12%\"\u003e\n \u003cp\u003e53.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.304347826086957%\"\u003e\n \u003cp\u003e2.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.695652173913043%\"\u003e\n \u003cp\u003e53.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.47826086956522%\"\u003e\n \u003cp\u003e2.08\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eTable 5 Analysis of variance (ANOVA) and Tukey tests for dental arch parameters and M3M MD\u0026deg; groups\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"646\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"8\" width=\"78.63777089783282%\"\u003e\n \u003cp\u003e\u003cstrong\u003eOne way ANOVA\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"21.362229102167184%\"\u003e\n \u003cp\u003e\u003cstrong\u003ePost hoc test\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"21.550387596899224%\"\u003e\n \u003cp\u003e\u003cstrong\u003eM3M MD\u003c/strong\u003e\u003cstrong\u003e\u0026deg;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"16.434108527131784%\"\u003e\n \u003cp\u003e\u003cstrong\u003eG1\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(MD\u003c/strong\u003e\u003cstrong\u003e\u0026deg;\u003c/strong\u003e\u003cstrong\u003e10-45\u0026deg;)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"15.348837209302326%\"\u003e\n \u003cp\u003e\u003cstrong\u003eG2\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(MD\u003c/strong\u003e\u003cstrong\u003e\u0026deg;\u003c/strong\u003e\u003cstrong\u003e﹥\u003c/strong\u003e\u003cstrong\u003e45\u0026deg;)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" width=\"15.03875968992248%\"\u003e\n \u003cp\u003e\u003cstrong\u003e(G3) \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;less-10\u0026deg;control\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e\u003cstrong\u003eP-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e\u003cstrong\u003eG1 vs G2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e\u003cstrong\u003eG1 vs G3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e\u003cstrong\u003eG2 \u0026nbsp; \u0026nbsp;vs \u0026nbsp; \u0026nbsp; G3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"11\" valign=\"top\" width=\"100%\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnteroposterior parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.682170542635658%\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.751937984496124%\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.682170542635658%\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"6.666666666666667%\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.682170542635658%\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\" width=\"31.627906976744185%\"\u003e\n \u003cp\u003e\u003cstrong\u003eP-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003eAnterior crowding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e2.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e1.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e3.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e2.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e1.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e*0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e*0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003ePosterior crowding\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e1.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e1.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e0.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e0.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e0.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e0.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e0.09\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003e\u0026nbsp;Overall arch crowding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e3.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e2.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e3.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e1.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e2.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e1.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e0.09\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003eAnterior teeth inclination\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e21.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e5.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e20.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e2.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e22.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e7.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e0.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003eArch length\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e38.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e2.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e39.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e0.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e36.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e2.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"11\" valign=\"top\" width=\"100%\"\u003e\n \u003cp\u003e\u003cstrong\u003eTransvers parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003eInter-canine width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e26.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e1.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e26.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e1.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e26.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e1.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e0.26\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003eInter 1\u003csup\u003est\u003c/sup\u003epremolar width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e35.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e1.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e35.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e2.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e35.21)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e2.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e0.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003eInter 2\u003csup\u003end\u003c/sup\u003epremolar width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e40.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e3.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e41.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e2.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e41.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e2.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003eInter 1\u003csup\u003est\u003c/sup\u003emolar width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e45.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e2.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e46.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e3.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e46.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e2.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e0.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e0.86\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"21.550387596899224%\"\u003e\n \u003cp\u003eInter 2\u003csup\u003end\u003c/sup\u003emolar width\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e52.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.751937984496124%\"\u003e\n \u003cp\u003e3.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e53.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.666666666666667%\"\u003e\n \u003cp\u003e3.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.682170542635658%\"\u003e\n \u003cp\u003e52.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.3565891472868215%\"\u003e\n \u003cp\u003e2.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.232558139534884%\"\u003e\n \u003cp\u003e0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.511627906976744%\"\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.372093023255815%\"\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;*\u003cem\u003eP\u0026nbsp;\u003c/em\u003e\u0026lt; 0.05\u003cbr\u003e**\u003cem\u003eP\u0026nbsp;\u003c/em\u003e\u0026lt; 0.01\u003cbr\u003e***\u003cem\u003eP\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001\u003c/p\u003e\n\u003cp\u003eTable 4 and 6 are available in the Supplementary Files section.\u003c/p\u003e\n\u003cp\u003eTable\u0026nbsp;\u003cspan style=\"color: rgb(29, 28, 29); font-family: Slack-Lato, Slack-Fractions, appleLogo, sans-serif; font-size: 15px; font-style: normal; font-variant-ligatures: common-ligatures; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;\"\u003e7 is not available with this version\u003c/span\u003e\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"clinical-oral-investigations","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cloi","sideBox":"Learn more about [Clinical Oral Investigations](http://link.springer.com/journal/784)","snPcode":"784","submissionUrl":"https://submission.nature.com/new-submission/784/3","title":"Clinical Oral Investigations","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Buccolingual, dental arch parameters, impacted mandibular third molars, mesiodistal, relationship, three-dimensional","lastPublishedDoi":"10.21203/rs.3.rs-2365433/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2365433/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjectives:\u003c/strong\u003e The purpose of this study was to three-dimensionally evaluate the relationship between the degree of bilateral impacted mandibular third molars (IM3M) angulation and the mandibular dental arch parameters in normal skeletal and dental malocclusion patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods: \u003c/strong\u003eIn\u003cstrong\u003e \u003c/strong\u003ethis retrospective cross-sectional comparative study, 120 adult subjects’ cone beam computed tomography (CBCT) images were three-dimensionally analyzed. The sample was divided into four groups according to degree of M3M buccolingual angulation (BL°); Group A \u0026lt;12° on the center of the ridge (N=30), Group B 12-24° off-center of the ridge (N=40), Group C \u0026gt;24° off center of the ridge (N=30), and Group D (control group with normal erupted bilateral M3M).The study subjects were further also divided into three groups according to IM3M mesiodistal\u0026nbsp; angulation (MD°); Group 1 from10° to 45°, Group 2\u0026gt; 45° and Group 3 (control group with normal erupted bilateral M3M, 0 -10°). Comparison within and between groups were performed using One-way ANOVA followed by Tukey's post hoc test, respectively. Correlation between IM3M, BL and MD angulation and mandibular arch parameter was calculated using Pearson's correlation coefficient.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eStatistically significant differences (P \u0026lt; .001) were founded between the IM3M BL° and anterior teeth inclination, arch length (AL) and inter second molar width (inter 2\u003csup\u003end \u003c/sup\u003eMW) as well as between the IM3M MD° with anterior crowding and the arch length (P \u0026lt; .001). Significant positive correlation was founded between IM3M BL° and anterior teeth inclination, and between IM3M MD° and anterior teeth crowding and inter 2nd MW. Significant negative correlation was observed between IM3M BL° and inter 1\u003csup\u003est\u003c/sup\u003e MW and 2\u003csup\u003end\u003c/sup\u003e MW.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eThe degree of buccolingual and mesiodistal angulation of the impacted mandibular third molars was associated with mandibular dentoalveolar changes. The increase in buccolingual angulation is associated with increase of anterior teeth inclination, and the decrease of 1\u003csup\u003est\u003c/sup\u003e and 2\u003csup\u003end\u003c/sup\u003e inter-molars width. The increase in mesiodistal angulations was associated with increase in anterior teeth crowding and 2\u003csup\u003end\u003c/sup\u003e inter-molars width.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical relevance:\u003c/strong\u003e Assessment of the relationship between the impacted mandibular third molars and the degree of arch discrepancy, and the position of mandibular incisors in the three planes of space might help in the decision-making process for extraction of the impacted third molars in adult patients.\u003c/p\u003e","manuscriptTitle":"Three-dimensional relationship between the degree of bilateral impacted mandibular third molars angulation and the mandibular dental arch parameters: a cross-sectional comparative study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-12-14 16:07:51","doi":"10.21203/rs.3.rs-2365433/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2023-02-28T20:28:28+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2023-02-21T00:18:31+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"bee28606-0e00-4735-b92e-9c711a4f50f3","date":"2023-02-11T07:58:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"02d85f86-2d16-4f66-8e76-d31b83a8fabb","date":"2022-12-29T08:29:14+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-12-22T09:35:54+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-12-12T06:25:49+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-12-12T06:25:46+00:00","index":"","fulltext":""},{"type":"submitted","content":"Clinical Oral Investigations","date":"2022-12-10T20:29:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"clinical-oral-investigations","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cloi","sideBox":"Learn more about [Clinical Oral Investigations](http://link.springer.com/journal/784)","snPcode":"784","submissionUrl":"https://submission.nature.com/new-submission/784/3","title":"Clinical Oral Investigations","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"bdd86572-0e06-4064-bb14-0f72abdcfb2f","owner":[],"postedDate":"December 14th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T21:00:14+00:00","versionOfRecord":{"articleIdentity":"rs-2365433","link":"https://doi.org/10.1007/s00784-023-05047-6","journal":{"identity":"clinical-oral-investigations","isVorOnly":false,"title":"Clinical Oral Investigations"},"publishedOn":"2023-05-15 20:52:52","publishedOnDateReadable":"May 15th, 2023"},"versionCreatedAt":"2022-12-14 16:07:51","video":"","vorDoi":"10.1007/s00784-023-05047-6","vorDoiUrl":"https://doi.org/10.1007/s00784-023-05047-6","workflowStages":[]},"version":"v1","identity":"rs-2365433","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2365433","identity":"rs-2365433","version":["v1"]},"buildId":"FbvkV6FR0MCFSLy54lSbu","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}