Three-dimensional condylar positions and forms associated with different anteroposterior skeletal patterns and facial asymmetry in Chinese adolescents

Mandibular condyle volumes are associated with facial asymmetry in patients with cleft lip and palate: A retrospective cohort study

This study compares condylar volumetric asymmetry and facial asymmetry in patients with cleft lip and/or palate (CLP) and controls. The mandibular condyle is important to facial growth, but its role in facial asymmetry for those with CLP has not been described. Condylar volumes and mandibular asymmetry were retrospectively calculated using Mimics Version 23.0 (Materialise, Leuven, Belgium) from patients with CLP undergoing computed tomography (CT) imaging and a cohort of controls. A total of 101 participants, 60 with CLP and 41 controls, had mean condylar volumetric asymmetry of 16.4 ± 17.4 % (CLP) and 6.0 ± 4.0 % (controls) (p = 0.0002). Patients with CLP who had clinically significant chin deviation (>4 mm) had more asymmetric condyles than those without significant chin deviation (p = 0.003). The chin deviated toward the smaller condyle in patients with facial asymmetry more often than in patients without facial asymmetry (81 % vs. 62 %, p = 0.033). While controls had some degree of condylar asymmetry, it tended to be milder and not associated with facial asymmetry. There is a greater degree of condylar volumetric asymmetry in patients with CLP compared to individuals in the general population. Clinically significant facial asymmetry in CLP is associated with a higher degree of condylar asymmetry, with the facial midline deviating toward the smaller condyle.

Mandibular asymmetry in patients with skeletal class I and skeletal class II Malocclusions: A cone-beam computed tomography study

OBJECTIVE

To study the difference in mandibular asymmetry between patients with skeletal Class I and skeletal Class II malocclusions and analyze the correlation between mandibular asymmetry and different facial skeletal sagittal patterns based on CBCT measurements.

METHODS

One hundred and twenty patients were selected according to the inclusion and exclusion criteria. Patients were divided into two groups (60 in the skeletal Class I group and 60 in the skeletal Class II group) based on ANB angles and Wits values. Patients' CBCT data were collected. Dolphin Imaging 11.0 was used to determine the mandibular anatomic landmarks and calculate the linear distance in patients in the two groups.

RESULTS

Intragroup comparison: in skeletal Class I group, measurements of the most posterior point of the condyle (Cdpost), the outer lateral point of the condyle (Cdlat), sigmoid notch point (Sn)), coronoid process point (Cop), gonion point (GO) and antimony notch point (Ag), right>left (P<0.05); in skeletal Class II group, measurements of Cdpost and Cop, right>left (P<0.05). Intergroup comparison: for measurements of GO and Ag, skeletal Class I group>skeletal Class II group (P<0.05). The asymmetry of the Ag and GO points was negatively correlated with the ANB angle (p<0.05).

CONCLUSION

Mandibular asymmetry was significantly different between patients with skeletal Class I and skeletal Class II malocclusions. The asymmetry of the mandible angle region in the former group was greater than that in the latter group, and the asymmetry of the mandibular angle was negatively correlated with the ANB angle.

Three-dimensional analysis of mandibular characteristics in patients with skeletal Class II malocclusion and chin deviation

INTRODUCTION

This study aimed to analyze adults with mandibular characteristics of skeletal Class II malocclusion with chin deviation.

METHODS

Seventy-five adult patients aged from 18 to 35 years were included and divided into 3 groups on the basis of sagittal skeletal pattern and chin deviation: skeletal Class I symmetry group, skeletal Class II symmetry group, and skeletal Class II asymmetry group (25 patients per group). Mandibular measurements on cone-beam computed tomography images were performed, and the differences between 2 sides in each group and the differences among the 3 groups were investigated.

RESULTS

Compared with the contralateral side, the deviated side of patients in the Class II asymmetry group showed significantly smaller condyle angle to midsagittal plane, condylar height, ramal length, and length of the mandibular body, whereas it showed a significantly larger distance from condylion to the midsagittal plane, ramus angle to the horizontal plane, and distance from gonion to the midsagittal plane. Most linear measurements in the Class II symmetry group were significantly smaller than those in the Class I symmetry group. These linear measurements on the contralateral side of the Class II asymmetry group showed no significant difference with the Class I symmetry group, and these measurements on the deviated side of the Class II asymmetry group showed no significant difference with the Class II symmetry group.

CONCLUSIONS

Length of the mandible, rotation of condyle, the inclination of the ramus, and position of gonion should be considered in subjects with skeletal Class II asymmetry when making diagnosis and treatment planning.

Comprehending the three-dimensional mandibular morphology of facial asymmetry patients with mandibular prognathism

Background

The purpose of this study was to elucidate the factors that cause facial asymmetry by comparing the characteristics of the mandibular morphology in patients with mandibular prognathism with or without facial asymmetry using three-dimensional computed tomography (3D-CT).

Methods

We studied 28 mandibular prognathism patients whose menton deviated by ≥ 4 mm from the midline (FA group, n = 14) and those with a < 4-mm deviation (NA group, n = 14). DICOM data from multislice CT images were reconstructed and analysed using 3D image analysing software. Mandibular structures were assessed via linear, angular, or volumetric measurements and analysed statistically.

Results

The lengths of the ramal and body components and condylar volume in the FA group were significantly greater on the nondeviated side than those on the deviated side. The mandibular body length of the nondeviated side in the FA group was significantly longer than that of the NA group. Other components of the FA group did not significantly differ from those of the NA group.

Conclusions

Imbalances in the sizes of the ramal and body components as well as the increased body length of the nondeviated side in the FA group compared with that of the NA group may contribute to facial asymmetry in patients with mandibular prognathism.

Mandibular vertical asymmetry in adult orthodontic patients with different vertical growth patterns: A cone beam computed tomography study

OBJECTIVE

To evaluate condylar and ramal vertical asymmetry in adult orthodontic patients with different vertical growth patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

The study sample consisted of 101 adult orthodontic patients (48 men and 53 women) divided into three groups according to their vertical growth patterns: high- (33 patients; mean age, 25.06 ± 6.05 years), low- (34 patients; mean age, 24.88 ± 5.22 years), and normal-angle (34 patients; mean age, 24.14 ± 4.26 years) groups. Condylar, ramal, condylar plus ramal height, and index measurements were performed using CBCT images and analyzed using one-way analysis of variance and post hoc Tukey tests.

RESULTS

There was no statistically significant difference in height measurements between right and left sides in each group, except a slight difference of approximately 0.5 mm for condylar height (CH) in the low-angle group (P < .05). No statistically significant gender differences were found for the values (P > .05). In the high-angle group, the ramal height (RH) and condylar plus ramal height (CH + RH) on both sides were found to be less than those of the low- (P < .001) and normal-angle groups (P < .017 and P > .017, respectively), and the asymmetry index values were slightly higher than those of the low- and normal-angle groups (P > .05).

CONCLUSIONS

The high-angle group showed statistically significantly smaller values of RH and CH + RH on both sides and statistically insignificantly higher asymmetry index values than the low- and normal-angle groups.