Evaluation of dental and skeletal asymmetry of class i, class ii and class III patients with different vertical skeletal pattern

The aim of this study is to evaluate dental and skeletal asymmetry of Class I, Class II and Class III patients with different vertical skeletal pattern. CBCT of 200 patients that sorted according to our criteria were divided into 9 subgroups by classifying with ANB angle in the sagittal direction and SNGoGn angle in the vertical direction. These subgroups include; 26 Class I hypodivergent, 31 Class I normodivergent, 24 Class I hyperdivergent, 19 Class II hypodivergent, 26 Class II normodivergent, 21 Class II hyperdivergent, 20 Class III hypodivergent, 17 Class III normodivergent and 16 Class III hyperdivergent patients. The data obtained from the CBCT images were transferred to the Dolphin 3D (version 11.9, Dolphin Imaging, Chatsworth, California) software and a total of 97 parameters (89 linear and 8 angular) were studied on these 3 dimensional hard tissue models. For statistical evaluation, One way ANOVA test was used to evaluate the difference between the groups and Tukey HSD test was used to compare the groups with each other. Paired-t test was used to compare the right and left parameters within groups. Dental asymmetry evaluation showed that in the intra-group comparison, the left side of the maxillary arch is longer than the right side in the Class II hypodivergent and normodivergent groups, right molar difference is more than left molar difference and left mandibular molar tooth is more mesially positioned than right mandibular molar tooth in the Class II hypodivergent group. In the inter-group comparison, right molar difference was found to be greater in the Class II and III groups than in the Class I group and overbite was found to be higher in the Class II group than in the Class I and Class III groups. While there was no statistically significant difference in the distance of the right and left gonion points to the sagittal plane in the intra-group comparison of asymmetry measurements made in maxilla and mandible and also no statistically significant difference in the mandibular plane angle and distance of the right and left gonion points to the sagittal plane in the inter-group comparison of asymmetry measurements made in maxilla and mandible, asymmetry was found in all other parameters. There was statistically significant difference in the anteroposterior and mediolateral dimensions of the condylar head in both intra- and intergroup comparisons of condylar asymmetry. In the inter-group comparison, condylar head was found to be longer in the mediolateral and anteroposterior direction in the Class I hyperdivergent and normodivergent groups than the other groups. In the intra-group comparisons of orthogonal asymmetry measurements in the coronal plane, it was found that in the sagittal direction orbita was more anteriorly positioned on the right side than the left side. In intra-group comparisons of orthogonal asymmetry measurements in the axial plane; condylar head is usually located lower on the left side than the right side. Inter-group comparison showed that teeth were located lower and the chin were located upper in Class III patients with normal vertical facial pattern than Class I and II patients in the same vertical group and condyle was located lower in the Class II patients than Class I and III patients. Consequently, asymmetry was found in almost all parameters of all groups, especially in maxillary-mandibular measurements. However, the values of asymmetry in statistically significant parameters are generally less than 2 mm, so these asymmetric values are clinically negligible.