title: Correlation between the disc status in MRI and the different types of traumatic temporomandibular joint ankylosis.
abstract: OBJECTIVE
  We aimed to investigate the correlation between the disc status in MRI and the different types of traumatic temporomandibular joint (TMJ) ankylosis.
  
  
  METHODS
  51 consecutive patients (69 joints), diagnosed with traumatic TMJ ankylosis with a residual condyle (Types A2 and A3), were included in this study. All patients had pre-operative MRI, which was reviewed to determine the disc shape, length and position. The results were compared using the Mann-Whitney test.
  
  
  RESULTS
  There were 37 joints of Type A2 ankylosis and 32 joints of Type A3. All joints of Type A2 and 27 joints of Type A3 (84.4%) definitely had a discernible disc, while 5 joints of Type A3 had no discernible discs. Among the discernible discs, the lateral disc of Type A2 and the whole disc of Type A3 had severe deformity, while the medial disc of Type A2 had mild deformity. The mean (standard deviation) disc length was 10.88 (1.19) mm in Type A2, but 7.50 (0.82) mm in Type A3. There was a significant difference between Types A2 and A3 (p < 0.05). As for the disc position, the intermediate position was found in all joints.
  
  
  CONCLUSIONS
  There is a correlation between the disc status and the different types of traumatic TMJ ankylosis. Therefore, MRI examination is needed to help treatment planning and predict post-operative TMJ function.
authors.affiliation: 1 Department of Oral and Maxillofacial Surgery, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, and Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China.
authors.forename: J S
authors.initials: JS
authors.lastname: Zheng
authors.forename: Z X
authors.initials: ZX
authors.lastname: Jiao
authors.forename: S Y
authors.initials: SY
authors.lastname: Zhang
authors.forename: C
authors.initials: C
authors.lastname: Yang
authors.forename: A
authors.initials: A
authors.lastname: Abdelrehem
authors.forename: M J
authors.initials: MJ
authors.lastname: Chen
authors.forename: D M
authors.initials: DM
authors.lastname: He
authors.forename: M J
authors.initials: MJ
authors.lastname: Dong
mesh_terms: D000293:Adolescent; D000328:Adult; D000844:Ankylosis / Q000145:classification* / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000473:pathology; D008875:Middle Aged; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging / Q000293:injuries*; D019224:Temporomandibular Joint Disc / Q000000981:diagnostic imaging / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000145:classification* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
keywords: MRI; disc shape; length; position; traumatic temporomandibular joint ankylosis