title: Magnetic resonance imaging findings and clinical symptoms in the temporomandibular joint in patients with mandibular continuity defects.
abstract: OBJECTIVE
  This study explored the morphologic changes and clinical symptoms related to the temporomandibular joint (TMJ) associated with long-term lack of mandibular continuity.
  
  
  METHODS
  The subjects were 20 patients (40 TMJs) who underwent mandibulectomy including the condyle or segmental mandibulectomy without mandibular reconstruction more than 6 months previous to the study. The 40 TMJs were classified into the following 3 groups: group I: TMJs with a major mandibular fragment including the mandibular body (n = 21), group II: TMJs with a minor mandibular fragment including only the condylar process or the mandibular ramus (n = 10), and group III: TMJs without a condyle (n = 9). All TMJs were examined with respect to disc position, condylar position, bony changes, and appearance of joint effusion on magnetic resonance imaging, as well as for the presence of joint or muscle pain and joint noise.
  
  
  RESULTS
  The rate of anterior disc displacement was 28.6% in group I, 10.0% in group II, and 100% in group III. All condyles in group I were located in the glenoid fossa. Seven of 10 condyles in group II were dislocated anteriorly out of the glenoid fossa. However, these condyles were situated in the intermediate zone of the disc. Osteoarthritic changes was found in 1 joint in group II. Joint effusion was not observed in group I. However, joint effusion was detected in the posterior region of the upper joint compartment in 7 of 10 TMJs in group H and in 8 of 9 TMJs in group III. In group II, the 7 TMJs with joint effusion were the same joints with anteriorly dislocated condyles. Clinical symptoms of TMJ pain, TMJ noise, or muscular pain were not found in any patients.
  
  
  CONCLUSIONS
  Partial mandibulectomy does not affect the relationship between the disc and the condyle or the bony condition of the TMJ. The disc without a condyle will become anteriorly displaced with time. The condyle not connected to the mandibular body often dislocates anteriorly out of the glenoid fossa, while retaining a normal relationship with the disc. Joint effusion, which is detected in nonfunctional TMJs, is not associated with an inflammatory reaction in the joint compartment.
authors.affiliation: First Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hamada
authors.forename: T
authors.initials: T
authors.lastname: Kondoh
authors.forename: K
authors.initials: K
authors.lastname: Nakaoka
authors.forename: K
authors.initials: K
authors.lastname: Seto
mesh_terms: D006801:Humans; D004204:Joint Dislocations / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008334:Mandible / Q000601:surgery*; D008335:Mandibular Condyle / Q000473:pathology / Q000601:surgery; D019647:Oral Surgical Procedures / Q000009:adverse effects*; D018709:Statistics, Nonparametric; D013704:Temporomandibular Joint / Q000473:pathology*; D019224:Temporomandibular Joint Disc / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000209:etiology* / Q000473:pathology*