Osteoporosis is a systematic skeletal disease that reduces bone mineral density (BMD) leading to a high risk of bone fracture with aging. While dual energy x-ray absorptiometry (DEXA) has been widely used to diagnose the osteoporosis, its 2D image limits its reliability to measure BMD. Otherwise, conventional medical computed tomography (CT) provides more comprehensive 3D images to improve the BMD based diagnosis. However, its high radiation dose limits access of patients. The objective of this study was to examine whether 3D dental cone beam CT (CBCT) can assess agedependent changes of volumetric BMD and morphology with less radiation dose than the medical CT.

Methods:​ After IRB approval, total of 138 clinical CBCT images were retrospectively obtained from 73 female and 65 male patients (20 to 69 years of age). The 3D images of cervical vertebral bodies (C2 and C3) were digitally isolated by removing lateral and posterior processes at 10 voxels from either side of the vertebral end plate. Non-bone voxels outside of the C2 and C3 were removed using a segmentation algorithm. A gray level, which is proportional to BMD, was obtained for each bone voxel and averaged to compute the mean gray value. Morphology including volume, heights, widths and concavities was also measured. Two-way ANOVA was performed with p<0.05.

Results:​ The C2 and C3 BMD of women over age 60 were significantly lower than those younger age 50 (p<0.010), while they were not significantly different between the age groups of men (p>0.061). The morphology of C2 and C3 were not significantly different between age groups of women (p>0.084).

Conclusion:​ The reduced BMD of older women likely results from postmenopausal demineralization of bone. The current findings suggest that CBCT can detect agedependent changes of cervical BMD providing baseline information to develop an alternative tool to diagnose osteoporosis.