Correlations Between Dentition and Temoromandibular Joint Condylar Bone Mineral Density

Objectives: Temporomandibular joint (TMJ) disorder (TMD) is more prevalent in women than men. However, the exact etiology for sex differences in TMD is not fully understood. We hypothesize that masticatory loading increases with a full dentition and may have different effects on TMJ between sexes. Thus, the objective of this study was to investigate sex differences between dentition and bone mineral density (BMD) of TMJ condylar bone.
Methods: IRB approval was obtained for retrospective analysis of cone beam computed tomography (CBCT) images taken from 24 male and 24 female, age-matched patients (40±22 years). Right and left mandibular condyles were digitally isolated from the 3D CBCT images. BMD was estimated using CT gray values. The number of teeth present was counted using the CBCT image. A t-test was used to compare the number of teeth between male and female groups. Pearson’s correlations between BMD and the number of teeth were examined.
Results: The number of teeth was not significantly different between male and female groups (p=0.434). Significant positive correlations were found between the number of teeth and the BMD of both right and left mandibular condyles for the female group (<0.014), but not for the male group (p>0.157).
Conclusions: The current findings suggest that masticatory loading associated with the number of teeth present can alter the properties of the female mandibular condyle. An unstable environment in the female mandibular condyle may contribute to the higher risk of TMD in females over males.