title: Mandibular asymmetry: a three-dimensional quantification of bilateral condyles.
abstract: BACKGROUND
  The shape and volume of the condyle is considered to play an important role in the pathogenesis of the mandibular deviation. Curvature analysis is informative for objectively assess whether the shape of the condyles matches that of the glenoid fossa. In this study, a three-dimensional (3-D) quantification of bilateral asymmetrical condyles was firstly conducted to identify the specific role of 3-D condylar configuration for mandibular asymmetry.
  
  
  METHODS
  55 adult patients, 26 males (26 ± 5 yrs) and 29 females (26 ± 5 yrs), diagnosed with mandibular asymmetry were included. The examination of deviation of chin point, deviation of dental midlines, inclination of occlusal plane, and depth of the mandibular occlusal plane were conducted. After the clinical investigation, computed tomography images from the patients were used to reconstruct the 3-D mandibular models. Then the condylar volume, surface size, surface curvature and bone mineral density were evaluated independently for each patient on non-deviated and deviated sides of temporomandibular joint.
  
  
  RESULTS
  Both the condylar surface size and volume were significantly larger on deviated side (surface size: 1666.14 ± 318.3 mm2, volume: 1981.5 ± 418.3 mm3). The anterior slope of the condyle was flatter (0.12 ± 0.06) and the posterior slope (0.39 ± 0.08) was prominently convex on the deviated side. The corresponding bone mineral density values were 523.01 ±118.1 HU and 549.07 ±120. 6 HU on anterior and posterior slopes.
  
  
  CONCLUSIONS
  The incongruence presented on the deviated side resulted in a reduction in contact areas and, thus, an increase in contact stresses and changes of bone density. All aforementioned results suggest that the difference existing between deviated and non-deviated condyles correlates with facial asymmetrical development. In mandibular asymmetry patients, the 3-D morphology of condyle on deviated side differ from the non-deviated side, which indicates the association between asymmetrical jaw function and joint remodeling.
authors.forename: Han
authors.initials: H
authors.lastname: Lin
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
authors.forename: Yi
authors.initials: Y
authors.lastname: Lin
authors.forename: Shuangquan
authors.initials: S
authors.lastname: Wan
authors.forename: Xin
authors.initials: X
authors.lastname: Shu
authors.affiliation: Department of Orthodontics, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Lingyuan Xilu No,56, Guangzhou 510055, China. dr-zheng@hotmail.com.
authors.forename: Yue
authors.initials: Y
authors.lastname: Xu
authors.forename: Youhua
authors.initials: Y
authors.lastname: Zheng
mesh_terms: D000328:Adult; D015519:Bone Density; D054893:Cone-Beam Computed Tomography; D005146:Facial Asymmetry / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008335:Mandibular Condyle / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging / Q000502:physiology; D055815:Young Adult