title: Diagnostic value of 4 criteria to interpret temporomandibular joint normal disk position on magnetic resonance images.
abstract: OBJECTIVE
  This study was undertaken to evaluate different criteria to establish normal disk position on magnetic resonance images.
  
  
  METHODS
  Magnetic resonance image findings of 137 consecutive patients with temporomandibular disorders and 23 asymptomatic volunteers were used in this study. Three calibrated observers interpreted the images individually. Four closed-mouth and 1 open-mouth criteria were tested for their ability to define normal and abnormal temporomandibular joint disk positions on magnetic resonance images.
  
  
  RESULTS
  For the 46 joints in the asymptomatic volunteers, the criterion that yielded the highest percentage of normal disk position diagnoses was the disk's intermediate zone (93.5%). Clock face criteria produced the following declining percentages of normal disk position diagnoses: 10 o'clock, 82.6%; 11 o'clock, 63.0%; and 12 o'clock, 39.1%. Similar results were obtained for the patients with temporomandibular disorders. In both groups, as the number of normal disk position diagnoses declined, the percentage of joints with a diagnosis of disk displacement with reduction increased. Conversely, the percentage of joints with a diagnosis of disk displacement without reduction (in the group of patients with temporomandibular disorders) did not appear to be substantially affected by the 4 closed-mouth disk position criteria.
  
  
  CONCLUSIONS
  These results suggest that the intermediate zone criterion for disk displacement is the more stringent criterion and the one that would yield the lowest number of false positives when the disk position is being judged in the closed-mouth sagittal view.
authors.affiliation: Department of Fixed Prosthodontics, Okayama University Dental School, Japan.
authors.forename: M G
authors.initials: MG
authors.lastname: Orsini
authors.forename: T
authors.initials: T
authors.lastname: Kuboki
authors.forename: S
authors.initials: S
authors.lastname: Terada
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuka
authors.forename: A
authors.initials: A
authors.lastname: Yamashita
authors.forename: G T
authors.initials: GT
authors.lastname: Clark
mesh_terms: D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D016037:Single-Blind Method; D019224:Temporomandibular Joint Disc / Q000033:anatomy & histology* / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000473:pathology*