title: Changes in temporomandibular joint sagittal disc position over time in adolescents: a longitudinal retrospective study.
abstract: BACKGROUND
  Temporomandibular joint (TMJ) disc displacement (DD) is a common finding in preorthodontic adolescents. The natural progression of this disorder has not been described with magnetic resonance imaging.
  
  
  METHODS
  The TMJs of a longitudinal sample of 94 preorthodontic adolescents were evaluated with magnetic resonance imaging to quantify sagittal disc position (SDP). The average time between imaging visits (V1 and V2) was 3.7 years (range, 1-6 years). Boys and girls had significantly different SDP values at V1, and therefore changes in SDP from V1 to V2 were analyzed separately for each sex.
  
  
  RESULTS
  The highest standard deviation was 0.58 mm for intraobserver measurement error. Regression analysis identified no significant association between change in disc status and time between imaging. There was no significant difference in mean change in SDP in girls or the right TMJ in boys. The boys' left TMJ showed a significant mean increase (0.87 mm of anterior displacement). Approximately 10% of right TMJs and 15% of left TMJs had more than 2 mm of anterior DD during the study. In the girls, approximately 8% of the right TMJs and 3% of the left TMJs showed more than 2 mm of posterior disc position changes from V1 to V2.
  
  
  CONCLUSIONS
  A natural progression in severity of DD in adolescents was not identified. Some subjects had large increases in anterior DD.
authors: Department of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors: Pablo
authors: P
authors: Kimos
authors: Brian
authors: B
authors: Nebbe
authors: Giseon
authors: G
authors: Heo
authors: Garnet
authors: G
authors: Packota
authors: Paul W
authors: PW
authors: Major
mesh_terms: D000293:Adolescent; D002648:Child; D018450:Disease Progression; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000473:pathology; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D012044:Regression Analysis; D012189:Retrospective Studies; D012737:Sex Factors; D019224:Temporomandibular Joint Disc / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000473:pathology*