Method: Subjects (n=15) were diagnosed with TMJ OA by clinical research diagnostic criteria for temporomandibular disorders (RDC/TMD) at their first appointment at the UNC Orofacial Pain Clinic. Age and gender-matched healthy controls with no history of TMJ arthritis (n=15) were selected through public advertisement. All subjects underwent complete RDC/TMD exam by an Orofacial pain specialist, and an Oral Maxillofacial Radiologist evaluated CBCTs. CBCT images were converted to 3D models, and subsequently registered. Sample-based average models of TMJ OA and healthy TMJs were generated by formulating a composite model of both the OA and control groups, respectively.
Result: Shape analysis evaluated morphological variation between the two composite models, as well as between individual condylar models and the constructed sample-based composites. There were statistically significant differences (P<0.05) in the magnitude and vectors visualized with color-coding between the OA and healthy TMJ sample-based composite models. The composite OA surface model revealed generalized flattening and bone resorption of the superior and lateral surfaces of the condyles relative to healthy TMJ condyles. However, these differences were less marked than in a previous study on a sample with chronic TMJ arthritis. Individual comparisons of the TMJ OA condyles to the composite healthy condyle model revealed resorption in 73.3% and 76.7% of the superior and lateral surfaces, respectively in the OA condyles.
Conclusion: Substantial changes in bone morphology are present even at the earlier clinical diagnostic stage of TMJ OA. The findings indicate the need for further investigations of the role of bone changes in the onset and progression of TMJ OA. Supported by NIDCR DE018962