3D Quantitative Morphometry of the Temporomandibular Joint

Objectives: Temporomandibular joint disorders (TMJD) disproportionally affect women, with unknown etiological factors contributing to TMJD development and progression. Joint morphometric features may be predictive of the development of TMJDs, and have been implicated clinically. The objective of this study was to establish a database of high-resolution 3D morphometric features of the temporomandibular joint (TMJ) for a geriatric normal population.
Methods: 18 cadaveric heads, 9 females (age 73.2±14.2 years) and 9 males (age 74.4±7.5 years) with no evidence of pathology underwent CBCT, and had their TMJs removed en bloc bilaterally. Contrast enhanced high-resolution 7 T preclinical MR scans using a proton density weighted sequence were obtained for intact TMJs. Surface models were generated including the mandibular condyle, temporal bone, articular disc, retrodiscal tissue and capsule by reconstruction segmentation. 3D morphometric features were assessed, with covariates accommodating variations in cephalometrics: skull length, skull width, skull height, bizygomatic breadth, and mandibular breadth at angle.
Results: Soft and hard tissue features of the intact TMJs were successfully captured, with an in-plane resolution of 0.234 mm x 0.234 mm, and slice thickness of 0.5 mm. Anatomical features were successfully registered in 3D: condylar major and minor axes, condylar height, condylar volume on the buckle and lingual sides, temporal fossa angle, disc thicknesses, disc widths and disc lengths. Descriptive statistics were calculated, and normalcy tested. Statistical differences between males and females and left-right asymmetry were determined, controlling for skull size and shape.
Conclusions: TMJ anatomy varies among individuals, with morphometric differences between sexes. Patient specific models of the TMJ using a database of morphologically normal anatomic parameters is supportive of musculoskeletal system modeling of the TMJ.