title: Evaluation of intra-articular distance narrowing during temporomandibular joint movement in patients with facial asymmetry using 3-dimensional computed tomography image and tracking camera system.
abstract: BACKGROUND
  Functional overloading can lead to disc displacement in the temporomandibular joint (TMJ), and a high incidence of disc displacement has been reported in patients with facial asymmetry. The aim of this study was to assess the dynamic condylar movement in patients (n = 26) with facial asymmetry using a simulation system with 3-dimensional computed tomographic images and tracking camera system.
  
  
  METHODS
  The intra-articular distance (IAD) between the condyle and glenoid fossa was recorded during TMJ movement as a parameter for functional overloading and compared between Group I with severe asymmetry and Group II with mild asymmetry.
  
  
  RESULTS
  The average IAD was shorter in Group I than Group II, especially at the lowest point (P < 0.05). The ratio of IAD narrowing in Group I was significantly larger than in Group II (P < 0.05). The mean IAD were slightly smaller on the deviated side (3.41 mm) than on the nondeviated side (3.55 mm) in Group I, even though there was no statistical significance. The maximum displacement in Group I was longer than in Group II and had no significant difference between deviated side and nondeviated side.
  
  
  CONCLUSIONS
  We suggested that the reduced IAD resulting from TMJ overloading can lead to internal derangement in severe facial asymmetry.
authors: Department of Oral and Maxillofacial Surgery, School of Dentistry, Dental Research Institute, Seoul National University, Republic of Korea.
authors: Ah Ryum
authors: AR
authors: Chang
authors: Department of Oral and Maxillofacial Surgery, School of Dentistry, Dental Research Institute, Seoul National University, Republic of Korea.
authors: Jeong Joon
authors: JJ
authors: Han
authors: Interdisciplinary Program in Radiation, Applied Life Science Major, College of Medicine, BK21, and Dental Research Institute, Seoul National University, Republic of Korea.
authors: Dae-Seung
authors: DS
authors: Kim
authors: Department of Oral and Maxillofacial Radiology, BK21, and Dental Research Institute, School of Dentistry, Seoul National University, Republic of Korea. Electronic address: wjyi@snu.ac.kr.
authors: Won-Jin
authors: WJ
authors: Yi
authors: Department of Oral and Maxillofacial Surgery, School of Dentistry, Dental Research Institute, Seoul National University, Republic of Korea. Electronic address: sjhwang@snu.ac.kr.
authors: Soon Jung
authors: SJ
authors: Hwang
mesh_terms: D000328:Adult; D000465:Algorithms; D001696:Biomechanical Phenomena; D002508:Cephalometry / Q000379:methods; D003198:Computer Simulation; D005146:Facial Asymmetry / Q000145:classification / Q000503:physiopathology*; D005260:Female; D057918:Fiducial Markers; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D004204:Joint Dislocations / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008335:Mandibular Condyle / Q000473:pathology* / Q000503:physiopathology; D010781:Photography / Q000379:methods; D016059:Range of Motion, Articular / Q000502:physiology*; D013314:Stress, Mechanical; D013701:Temporal Bone / Q000473:pathology*; D013704:Temporomandibular Joint / Q000473:pathology* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods; D014584:User-Computer Interface; D055815:Young Adult
keywords: 3D TMJ simulation; Condylar maximum displacement; Facial asymmetry; Intra-articular distance changes