Internal-Density Calibration of Mandibular Condyles for Osteoporosis Screening Among Females

Objectives: Early diagnosis of osteoporosis is critical to lowering bone fracture risk. Despite prior studies on opportunistic screening using readily accessible cone-beam computed tomography (CBCT), the inconsistencies between its gray values (GV) and bone mineral density (BMD) persist. Our aim was to evaluate the effectiveness of mandibular condyle trabecular bone density (MCTBD) obtained via CBCT-based patient-specific internal calibration in osteoporosis screening.
Methods: We conducted a cross-sectional study on 357 de-identified CBCT DICOM files of dentate females. ImageJ software 2.0 was used to determine the gray value (GV) of bilateral mandibular condylar heads’ trabecular portion at its greatest mediolateral dimension. MCTBD was derived through an internal calibration formula involving GV of condyles, soft tissue, and air. A paired t test was performed to compare both sides of the MCTBDs. On a subset of population (n-110), who had undergone a standard of care, dual-energy X-ray absorptiometry (DXA) scan within ±5 years of CBCT examination, the hip and femur variables were correlated with the MCTBD.
Results: A significant correlation (p < 0.001) was found between right MCTBD and total hip BMD (r = 0.48), total hip T score (r = 0.56), and femur T score (r = 0.44). Patients with low bone mass (hip T score <-1) had a highly significant 30% reduction in right MCBD compared to healthy patients, while there is no such difference in the left condyle (p = 0.13). Around 45 - 60 years of age, there was a notable (p < 0.001) difference in the MCTBD between two sides, with the right side being denser. The linear regression model involving right MCTBD, body mass index, and age showed 80% sensitivity, 66.6% specificity, and 79% area under the ROC in predicting low bone mass.
Conclusions: Our study revealed a distinct correlation of right MCTBD with other joints' BMD during menopause, suggesting a potential for improved osteoporosis screening through dental CBCT. It further warrants investigations into its correlation with degenerative joint diseases.