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Purpose The purpose of this was to construct finite element (FE) models based on computed tomography (CT) data of individual patients during orthodontic treatment and to evaluate the relationship between strain energy density (SED) in the temporomandibular joint (TMJ) disc and the facial morphology of three skeletal patterns (Class 1–3) by cephalometric analysis. Methods Cephalometric analyses were performed on 53 patients. FE models based on the CT images of each patient were constructed, and the mean SED in the bilateral TMJ disc was calculated. The relationships between SED and the cephalometric parameters were evaluated. Results SED was significantly greater in Classes 1 and 2 than in Class 3 ( p  < 0.05). Positive correlations were observed between SED and convexity, ANB angle ( p  < 0.01), and gonial angle in Class 1 ( p  < 0.05). A negative correlation was observed between SED and facial angle in Class 3 ( p  < 0.05). Overall, correlations were found between SED and facial angle, convexity, mandibular angle, Y-axis, SNB, ANB angle, and overjet ( p  < 0.05). Conclusion Increased SED in the TMJ disc was associated with clockwise mandibular rotation and superior posterior positioning. Mandibular morphology primarily affected SED, with facial angle, convexity, and ANB being useful predictors of TMJ dysfunction.

Objective This study aimed to investigate the normal volumetric space and variations in the measurements of different landmarks in adults with different skeletal relations of the maxilla and the mandible based on CBCT data. The study also analyses these landmarks to locate any correlations. Background Numerous studies in orthodontics have found a relationship between orthodontic treatment and changes in the anatomy and function of the airway. Severe changes in airway morphology can cause breathing difficulties, lower quality of life, and even result in life-threatening conditions such as obstructive sleep apnoea. Consequently, orthodontic diagnosis and treatment planning require a thorough understanding of the airway space and its function. Methods The present retrospective study was conducted using CBCT records of 120 adult patients, containing 40 samples of each skeletal class (20 males and 20 females). The boundaries were defined for the 3 major regions: the nasopharynx, the oropharynx, and the hypopharynx. Various measurements were recorded across these regions, as well as selective cephalometric landmarks. The obtained data was used to calculate average and standard deviation, while regression analysis was used to evaluate correlations and t-test was used to test statistical significance of gender differences. Results The results demonstrate that skeletal Class III individuals exhibit a reduced airway volume in the nasopharynx compared to other groups, whereas skeletal Class II individuals displayed a diminished airway volume in the hypopharynx. A strong correlation was observed for Sella turcica parameters. There were no significant differences in skeletal parameters across genders. Nasopharynx cavity volume demonstrated significant differences between skeletal Class I–Class III as well as between skeletal Class II–Class III. Hypopharynx cavity volume also demonstrated significant differences between skeletal Class I–Class II and between skeletal Class II–Class III. Conclusion The major findings are the presence of a reduced nasopharyngeal volume in skeletal Class III malocclusions while skeletal Class II individuals displayed a diminished hypopharyngeal volume, making these critical areas to consider during the diagnostic and orthodontic treatment planning stages. This study also revealed a consistent correlation between Sella turcica parameters across various facial skeletal profiles, with skeletal Class II patients exhibiting a distinct pattern and skeletal Class I and Class III demonstrating an average relationship.

Background Tongue position plays a vital role in craniofacial development, influencing skeletal structure and dental alignment. This study aims to assess tongue position and investigate its relationship with various dentofacial skeletal patterns using a novel cephalometric analysis method. Methods This cross-sectional study included 550 orthodontic patients (ages 6–50) with pre-treatment lateral cephalograms. Participants were divided into mixed dentition (6–11 years) and permanent dentition (12–50 years) groups and classified into three sagittal skeletal patterns (Class I, II, III) based on ANB angle and three vertical patterns (high, average, low angle) based on FMA angle. Statistical analyses were selected according to data distribution and variance. Correlation analysis included Spearman’s rank and partial correlation, the latter of which adjusted for age, FMA, and adenotonsillar hypertrophy. Results In the mixed dentition group, tongue position showed no significant variation by vertical pattern. In the permanent group, patients with low angles had a lower tongue tip. Class III patients exhibited an anterior and inferior tongue tip, while Class II patients had a higher tongue tip in the permanent group, after controlling for adenotonsillar hypertrophy, age, and FMA. Conclusions This study introduces a simplified method for measuring tongue position. A superior tongue tip correlates with skeletal Class II malocclusion, while an anterior and inferior tongue tip and lower tongue position are linked to skeletal Class III malocclusion. A lower tongue tip is also associated with low angle skeletal patterns.

Background This study aimed to assess the relationship between sagittal skeletal patterns and nasal morphology in Iranian orthodontic patients. Methods This descriptive study included 120 orthodontic patients aged 18–30 years with different sagittal skeletal pattern, classified based on ANB angle and Wits appraisal. A lateral cephalogram and frontal- and profile-view photographs were obtained from the patients. Nasal length was measured on both the cephalograms and photographs. Nasal parameters were assessed and compared using the Chi-square test, independent t-test, ANOVA, and Tukey’s post hoc test (α = 0.05). Results Of all participants, 77 (64.2%) were female and 43 (35.8%) were male, with a mean age of 22.42 ± 4.39 years. The three sagittal skeletal classes of malocclusion (Class I, II, and III) demonstrated distinct nasal morphology characteristics. No significant differences were found among the three classes in nasal length, nasal depth 1 (the perpendicular distance between point Pe and the line drawn from N to Sn), nasal depth 2 (the distance between points Ac and Pr), intercanthal distance, or facial height ( P  > 0.05). However, alar width, nasolabial angle, and dorsum convexity were significantly greater in Class II patients compared to Class I and III patients, while the nasomental angle and columella convexity were significantly greater in Class III patients compared to Class I and II patients ( P  < 0.05). Conclusion This study revealed significant differences in nasal morphology among different sagittal skeletal patterns, emphasizing the importance of considering nasal features in orthodontic treatment planning. Gender-specific variations further underscore the value of personalized treatment approaches for optimal aesthetic and functional outcomes.

Background Many indices have been suggested to help orthodontists in predicting the ideal dental arch width. One of these was Pont’s index which was established by Pont. He suggested equations to predict the ideal maxillary dental arch width (interpremolar and intermolar) from the combined mesiodistal width of the maxillary incisors. This study aimed to test the applicability of Pont’s index as an orthodontic diagnostic tool in Egyptian population and to compare the results with those obtained from studies of different ethnic subjects. Methods This study was performed using dental casts of 184 Egyptian individuals (82 males and 102 females; age range, 19–24 years). The casts were divided into 46 casts with normal occlusion, 46 casts with class I, 46 casts with class II and 46 casts with class III malocclusion, according to Angle’s classification. Alginate impressions were taken for all patients and poured immediately using dental plaster. The real models were transformed into digital models using three-dimensional laser scanner to allow digital model analysis. Predicted arch widths were calculated using Pont’s equations. The predicted values were compared to the measured values. Results Intra class correlation coefficient (ICC) (absolute agreement) between measured and predicted arch widths was determined. Poor absolute agreement was found between measured arch width values and the corresponding values calculated according to Pont’s index. Conclusion According to the results of this study, Pont’s index is not a reliable method for predicting the ideal dental arch widths in Egyptian populations.

Background The aim of the study was to assess the thickness of the soft tissue facial profile (STFP) in relation to the skeletal malocclusion, age and gender. Methods All patients, aged 7–35 years, who were seeking orthodontic treatment at the Department of Orthodontics, Medical University of Warsaw between 2019 and 22 were included in the study. All patients had lateral head radiographs taken before the treatment. The cephalometric analysis was performed including the STFP analysis. The patients were allocated to one of six groups based on age and skeletal relations (ANB angle). The minimum number of patients in each group was 60 with equal gender distribution. The STFP analysis included ten linear measurements. Results A total of 300 patients were included in the study and allocated to five groups. Group 6 (growing patients with skeletal Class III malocclusion) was not included in the study as it failed to achieve the assumed group size. There were significant differences in the thickness of the STFP in relation to the skeletal malocclusions. Adults with skeletal Class III malocclusion had significantly thicker subnasal soft tissues compared to patients with skeletal Class I and Class II malocclusions. The thickness of the lower lip in patients with Class II skeletal malocclusion was significantly bigger compared to the other groups. Children and adolescents with Class II malocclusions had thicker lower lip in comparison to the group with Class I malocclusion. The majority of the STFP measurements were significantly smaller in children and adolescents compared to adults. The thickness of the STFP in males was significantly bigger in all age groups compared to females. Conclusions The thickness of facial soft tissues depends on the patient’s age and gender. The degree of compensation of the skeletal malocclusion in the STFP may be a decisive factor during orthodontic treatment planning regarding a surgical approach or a camouflage treatment of skeletal defects.

Background This study aimed to investigate the facial soft tissue characteristics of patients with different types of malocclusion. Methods The 3dMD scanning data of patients with malocclusion admitted to our hospital from January 2018 to April 2022 were analyzed retrospectively. Forty-seven patients with Class I malocclusion, 43 patients with Class II malocclusion and 44 patients with Class III malocclusion were selected. All patients underwent 3dMD scans prior to orthodontic treatment. Then the differences in the 3D morphological parameters of the facial soft tissues were compared between different sexes and different types of malocclusion. Spearman’s correlation was further used to analyze the correlation between each parameter and the classification of malocclusion. Results In the Class I group and Class II group, there were no significant differences in the 3D morphometric parameters of malocclusion patients of different sexes ( P  > 0.05). There were significant differences between Al (R)-AL (L), Ac (R)-Ac (L), Prn-Ac (L), n-Prn-Sn, and Al (R)-Al (L)/Ac (L)-Ah (L) values among the three groups of patients. Spearman correlation analysis showed that Ac (R)-Ac (L) and Al (R)-Al (L)/Ac (R)-Ac (L) were correlated with the type of malocclusion. Conclusion Differences in facial soft tissues exist in patients with Class I, II, and III malocclusion. 3dMD technique may be helpful in developing an effective treatment plan prior to orthodontic treatment.

The objective of this study was to compare the aging changes of the dental arches in patients treated without extractions and untreated normal occlusion subjects after a four-decade follow-up. This retrospective study evaluated two groups: The Treated Group (Group T) comprised 16 patients (6 male; 10 female) presenting with Class I or Class II malocclusions treated orthodontically without extractions. Dental models were evaluated 3 stages: T1 (pretreatment, 13.20 years), T2 (posttreatment, 15.07 years) and T3 (long-term posttreatment, 50.32 years). The Untreated Group (Group UT) consisted of 22 untreated normal occlusion individuals. The dental casts were evaluated at the ages of 13.32 (T1), 17.82 (T2) and 60.95 years (T3). The dental casts were digitized and the irregularity index, intercanine, interpremolar and intermolar widths, overjet and overbite, arch length and perimeter were measured. Intergroup comparisons were performed with independent t tests ( P  < 0.05). From T1 to T2, the treated group showed maxillary and mandibular crowding and overjet decrease and a maxillary interpremolar and intermolar width increase compared to the untreated group. From T2 to T3, a greater maxillary and mandibular crowding increase and a greater arch length decrease were observed in the treated group compared to the normal occlusion subjects. Overbite increased in the treated group and decreased in the untreated group. The maturational changes of treated patients were different from untreated normal occlusion subjects. Relapse might have contributed for the greater changes observed in incisor crowding and arch length observed in orthodontically treated patients. The aging changes of untreated normal occlusions and nonextraction treated patients, after a four-decade follow-up, proved to be different, indicating that relapse of orthodontic treatment played a role in aging changes of treated patients.

Background The objectives of this paper are to (1) study use of soft tissue analyses advocated by Steiner, Ricketts, Burstone, Sushner and Holdway to develop soft tissue cephalometric norms as baseline data for sagittal lip position in Northeast Chinese adult population, (2) compare the sagittal lip positions in different skeletal malocclusions and (3) compare the sagittal lip positions in Northeast Chinese adults with other reported populations. Methods Lateral cephalometric radiographs of subjects were taken in natural head position. Radiographs were manually traced and five reference lines - Sushner, Steiner, Burstone, Holdway and Ricketts, were used. The linear distance between the tip of the lips and the five reference lines were measured. Statistical analysis was done using the Statistical Package for Social Sciences (SPSS) 21. Descriptive analysis was done for each variable for each subject. Coefficient of variation between lip positions as assessed by reference lines was determined. Post hoc Tukey’s test was used for comparison of the mean cephalometric values of three skeletal malocclusions. The level of significance for the analysis was set at p  < 0.05. Results The findings showed significant difference in the sagittal lip positions in different skeletal malocclusions. There was variation in consistent reference line in each skeletal malocclusion. The S2 line was the most consistent reference line in skeletal class I and class II group. The B line was the most consistent line in skeletal class III. In skeletal class II group, upper lips were the most protrusive and lower lips were retrusive than in skeletal class I and class III groups. In case of skeletal class III group, upper lips were retrusive and lower lips were more protrusive than in skeletal class I and class II groups. Conclusions The sagittal lip positions were found to be associated with the skeletal malocclusion pattern. Northeast Chinese population has protrusive upper and lower lip in comparison to Caucasians. Each skeletal malocclusion group showed different preferable reference lines for analysis of sagittal lip position.

Backgound This study cephalometrically evaluated the posterior teeth angulation changes of anterior open-bite non-extraction and extraction treatment in the permanent dentition, with anterior vertical elastics. Methods The sample consisted of initial and final lateral headfilms of 60 patients divided into 2 groups: Group 1 consisted of 30 patients treated with non-extraction with an initial mean age of 15.26 years and treated with fixed appliances for a mean period of 2.46 years. Group 2 consisted of 30 patients treated with extractions, with an initial mean age of 14.03 years, and treated with fixed appliances for a mean period of 2.49 years. Within-group treatment changes were evaluated with paired t tests. Results were considered statistically significant at P  < 0.05. Results The mandibular posterior teeth were significantly uprighted in both groups with both treatment protocols. Conclusions Correction of anterior open bite with either non-extraction or extractions with continuous archwires and vertical anterior elastics uprights the mandibular posterior teeth.