title: Regional 3D superimposition to assess temporomandibular joint condylar morphology.
abstract: OBJECTIVE
  To investigate the reliability of regional three-dimensional registration and superimposition methods for assessment of temporomandibular joint condylar morphology across subjects and longitudinally.
  
  
  METHODS
  The sample consisted of cone beam CT scans of 36 patients. The across-subject comparisons included 12 controls, mean age 41.3 ± 12.0 years, and 12 patients with temporomandibular joint osteoarthritis, mean age 41.3 ± 14.7 years. The individual longitudinal assessments included 12 patients with temporomandibular joint osteoarthritis, mean age 37.8 ± 16.7 years, followed up at pre-operative jaw surgery, immediately after and one-year post-operative. Surface models of all condyles were constructed from the cone beam CT scans. Two previously calibrated observers independently performed all registration methods. A landmark-based approach was used for the registration of across-subject condylar models, and temporomandibular joint osteoarthritis vs control group differences were computed with shape analysis. A voxel-based approach was used for registration of longitudinal scans calculated x, y, z degrees of freedom for translation and rotation. Two-way random intraclass correlation coefficients tested the interobserver reliability.
  
  
  RESULTS
  Statistically significant differences between the control group and the osteoarthritis group were consistently located on the lateral and medial poles for both observers. The interobserver differences were ≤0.2 mm. For individual longitudinal comparisons, the mean interobserver differences were ≤0.6 mm in translation errors and 1.2° in rotation errors, with excellent reliability (intraclass correlation coefficient >0.75).
  
  
  CONCLUSIONS
  Condylar registration for across-subjects and longitudinal assessments is reliable and can be used to quantify subtle bony differences in the three-dimensional condylar morphology.
authors.affiliation: Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA.
authors.forename: J
authors.initials: J
authors.lastname: Schilling
authors.forename: L C R
authors.initials: LC
authors.lastname: Gomes
authors.forename: E
authors.initials: E
authors.lastname: Benavides
authors.forename: T
authors.initials: T
authors.lastname: Nguyen
authors.forename: B
authors.initials: B
authors.lastname: Paniagua
authors.forename: M
authors.initials: M
authors.lastname: Styner
authors.forename: V
authors.initials: V
authors.lastname: Boen
authors.forename: J R
authors.initials: JR
authors.lastname: Gonçalves
authors.forename: L H S
authors.initials: LH
authors.lastname: Cevidanes
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D003196:Computer Graphics; D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography / Q000379:methods* / Q000706:statistics & numerical data; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008137:Longitudinal Studies; D008335:Mandibular Condyle / Q000000981:diagnostic imaging* / Q000601:surgery; D008953:Models, Anatomic; D015588:Observer Variation; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000601:surgery; D015203:Reproducibility of Results; D012984:Software; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging / Q000601:surgery
keywords: condyle; measurements; morphology; registration; reliability; temporomandibular joint