Temporomandibular joint osteoarthritis (TMJ OA) is a degenerative bone disease that has been observed more in women than men. However, the causes of TMJ OA are multifactorial in nature and its diagnostic criteria are highly controversial. Recently, researchers have suggested using cone beam computed tomography (CBCT) to diagnose TMJ OA by counting imaging characteristics of mandibular condyle. The objective of this study was to examine whether bone mineral density (BMD) distribution in the TMJ condyle and mandibular facial morphology are associated with TMJ OA using patients’ CBCT images.
Methods: CBCT images of 35 adult patients (16 male and 19 female between 20 and 50 years old were retrospectively examined. Experienced clinicians including a dental radiologist determined TMJ OA counts. Right and left mandibular condyles were digitally cropped from CBCT images. A histogram of gray level that is proportional to BMD was obtained for each TMJ condyle. Mean, standard deviation (SD), fifth percentile low and high values (Low5 and High5) of the gray level histogram were determined. The CBCT based cephalometric images were used to measure the mandibular morphology.
Results: Female group had significantly higher values of TMJ OA counts, mean and SD at the right mandibular condyle, High5 at both sides, and all gray value parameters for total (right + left) compared to male group (p<0.05). TMJ OA counts showed negative correlation with volume (p=0.005) and mean, Low5, High5. Specifically, antero-lateral (AL) region TMJ OA count showed significant interaction with gray value parameters (p<0.05).
Conclusion: Female has more TMJ OA changes in mandibular condyle compared to male and BMD distribution confirmed its trend with significant positive correlations of gray value parameters. CBCT based gray value parameters of the condyles may provide useful information in patients for TMJ OA risk assessment especially when AL region of the condyle is captured.