Science Letters

3D Condylar Forms and Positions in Association with Various Vertical Skeletal Patterns in Chinese Adolescents

Mehjabeen Al Jabri, Yang Zhang, Lin Wang, Junqing Ma*

Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, 210029, Nanjing, China

Abstract

In this study, the relationship between condylar asymmetry and the positions of the chin among various vertical skeletal patterns was evaluated with the use of images in cone-beam computed Tomography (CBCT). The CBCT scans of 75 Chinese adolescent patients attending the orthodontic clinics (aged 12-16 years, 42 girls and 33 boys) with 26 normodivergent, 25 hypodivergent and 24 hyperdivergent were selected. Bilateral reconstruction of the condyles of the subjects and the evaluation of asymmetries in the condyles and in the position of the chin was performed using 23 linear and angular measurements. The absolute difference in the values between that of the left and right side to that of the smaller side values contributed in the calculation of proportions of condylar asymmetries among different skeletal groups. The values for left condylar height (HCL), angle of condylar growth directions and horizontal plane (LHrp), angle of point (R-CyH), the most superior point on the right condyle to (R-Go) gonion, the midpoint on the contour connecting the ramus and the body of the mandible on the right lateral view to (R-Me) menton, the most inferior point on the mandibular symphysis (RCGM), angle of point (L-CyH), the most superior point on the left condyle to (L-Go) gonion, the midpoint on the contour connecting the ramus and the body of the mandible on the left lateral view to (L-Me) menton, the most inferior point on the mandibular symphysis (LCGM),distance of L-CyH) and the most superior point on the left condyle to (Meplane) horizontal crossing menton (LcyMe) showed significant differences amongst the three skeletal groups (p<0.05).Differences for CrP, Cy-Shr, Cy-Ssg, SgP, LC and HC amongst the condyles of both sides (right and left) surpasses a total of 20% in ratio for more than 40% of all the subjects. Significant variation of condylar asymmetries amongst the three groups, with the condyles in vertical position (Cy-Ssg) and angle of the condyle to the sagittal plane (SgP) having significant and positive relation to the position of the chin were determined .

Keywords CBCT, condylar asymmetries, vertical skeletal patterns, 3D reconstruction.

Received June 20, 2016 Accepted September 01, 2016 Abstract Published September 25, 2016 Manuscript Published December 15, 2016

*Corresponding author Junqing Ma E-mail jma@njmu.edu.cn Tel +86-25-85031976