Mandibular condyle bone mineral density measurement by quantitative computed tomography: A gender-related difference in correlation to spinal bone mineral density

We conducted volunteer studies to assess age-related changes of mandibular condyle bone mineral density (BMD) and its correlation to the spinal BMD. Quantitative computed tomography was performed on the condyles and spines (L1–3) of 210 healthy subjects (114 men and 96 women, aged 5–85 years). A separate study was performed on 73 young student subjects (39 men and 34 women, aged 23–25 years). The mandibular condyle BMD showed a decrement rate similar to spinal BMD in men, but in women the decrement rate of the mandibular condyle BMD was lower than that of the L1–3 BMD. On the other hand, correlation coefficients in BMD between the mandibular condyle and spine were similar in women and men. Gender-related differences were found to be dramatic when assessed in the young student group; the mandibular condyle and spinal BMDs were highly correlated in women (r = 0.82, p< 0.0001), but no correlation was found in men (r = 0.22). Taken together, these results suggest that the same regulatory mechanisms exist in the mandibular condyle and spine BMDs. However, aside from the spine BMD, additional undefined factor(s), including mechanical stress from the occlusion, may be involved in maintaining mandibular BMD.