title: [Temporomandibular joint osteoarthrosis in patients receiving orthodontic treatments: a clinical investigation].
abstract: OBJECTIVE
  To investigate the clinical characteristics of temporomandibular joint osteoarthrosis (TMJOA) in patients with malocclusion before orthodontic treatment and evaluate the radiographic changes of temporomandibular joint during treatment.
  
  
  METHODS
  Complete clinical recordings of 10,032 patients referring to the Orthodontic Department of Peking University School and Hospital of Stomatology from January 1998 to December 2003 were reviewed in present study. Patients with a history of previous orthodontic treatment, jaw surgery, facial trauma or systemic diseases which could potentially involve temporomandibular joint were excluded. The detection rate of TMJOA was calculated and its association with the possible risk factors of age, gender and malocclusion classifications was analyzed using the method of chi-square and multivariate logistic regression analysis. The clinical and radiographic characteristics were investigated and the radiographic findings before and after treatment were compared to evaluate the orthodontic effect on the articular bony structures.
  
  
  RESULTS
  The detection rate of TMJOA in 10,032 patients before orthodontic treatment was 1.6% (159/10,032) and significantly higher in females (1.9%, 124/6,409) than in males(1.0%, 35/3,623)(chi-square = 13.925, P < 0.01).The detection rate increased positively with age (chi-square = 136.381, P < 0.01). Multivariate logistic regression analysis showed that patients with Angle II malocclusion were 1.683 times more likely to suffer from TMJOA compared with patients with Angle I malocclusion(Wald chi-square = 9.007, OR = 1.683, P < 0.01), while there was no significantly difference between the patients with Angle III and I malocclusion. Among the 85 TMJOA patients who finished their orthodontic treatments, 63 patients (74.1%, 63/85) maintained stable articular bony structure and the remaining 9(10.6%, 9/85) and 13 (15.3%, 13/85) patients showed recovering and deteriorating signs respectively according to the radiographs.
  
  
  CONCLUSIONS
  The detection rate of TMJOA associated with age, gender and malocclusion classifications. Stable articular bony structure was maintained in the majority of the TMJOA patients (74.1%, 63/85) during the orthodontic treatments.
authors.affiliation: Center for Temporomandibular Joint Diseases and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081,China.
authors.forename: Zhi-Peng
authors.initials: ZP
authors.lastname: Sun
authors.forename: Bing-Shuang
authors.initials: BS
authors.lastname: Zou
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009971:Orthodontics, Corrective; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis / Q000453:epidemiology*; D055815:Young Adult