title: Longitudinal study on TMJ disk status and its effect on mandibular growth.
abstract: OBJECTIVE
  This longitudinal study assessed the potential contribution of temporomandibular joint (TMJ) disk status over mandibular linear and angular changes.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Edmonton, Alberta, Canada.
  
  
  METHODS
  Seventy-three adolescent subjects attending TMJ or orthodontic clinics with or without TMJ disk abnormality were followed during a mean 3 years 7 months. From this sample 39 subjects underwent orthodontic treatment.
  
  
  METHODS
  Disk displacement and disk length measurements taken from MRIs were utilized to evaluate the TMJ disk status. Mandibular changes were quantified from cephalometric radiographs by superimposing the mandible around the internal cortex of the posterior wall of the mandibular symphysis. Fishman's skeletal maturation system was used to calculate the percentage of mandibular growth remaining during the follow-up. This expected mandibular growth was factored out through a statistical normalization process applied to the actual difference between the initial and final mandibular measurements. In addition, previous orthodontic treatment was also considered for the analysis. A multiple analysis of variance (MANOVA) was used to evaluate interaction between the independent variables (TMJ disk status and previous orthodontic treatment) over the dependent variables (mandibular ramus, mandibular body, mandibular length and gonial angle measurements).
  
  
  RESULTS
  No significant contribution was found of any of the evaluated variables or its interactions over the mandibular measurements.
  
  
  CONCLUSIONS
  No evidence was found of TMJ disk abnormality as an associated significant factor with mandibular dimensional changes. The findings have to be evaluated with caution because of some limitations identified in this study.
authors.affiliation: University of Alberta, Edmonton AB T6G 2N8, Canada., carlosflores@ualberta.ca
authors.forename: C
authors.initials: C
authors.lastname: Flores-Mir
authors.forename: L
authors.initials: L
authors.lastname: Akbarihamed
authors.forename: B
authors.initials: B
authors.lastname: Nebbe
authors.forename: G
authors.initials: G
authors.lastname: Heo
authors.forename: P W
authors.initials: PW
authors.lastname: Major
mesh_terms: D000293:Adolescent; D002508:Cephalometry; D002648:Child; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008334:Mandible / Q000254:growth & development*; D015999:Multivariate Analysis; D009971:Orthodontics, Corrective; D019224:Temporomandibular Joint Disc / Q000503:physiopathology*; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology*