Regional Variation of Bone Mineralization in the Human Mandible

Objectives: In an animal model, masticatory force stimulated more bone turnover in alveolar bone (AB) surrounding teeth than in other areas of oral bone. This resulted in a higher variability of degree of bone mineralization (DBM) in AB surrounding teeth determined by micro-computed tomography (micro-CT). The objective of this study was to determine if the regional variation of DBM can be assessed using clinical cone beam computed tomography (CBCT) for human mandibles.

Methods: After approval of IRB, 15 clinical CBCT images were identified from 350 CBCT images in patient database. These patients (7 males and 8 females, mean 18.9yrs) were all healthy individuals without any medical complications or medications. Bone voxels in CBCT images were segmented from non-bone voxels using a heuristic algorithm. The 3D AB region of left mandibular premolar region was digitally isolated within 1 mm outside the root surface and the basal control bone (CB) was determined at 0.6 mm inside mandibular bone borders. The DBM histogram was obtained by calibrating a CT attenuation value of each bone voxel to a mineral density using known phantoms. Mean, standard deviation (SD), and coefficient of variation (COV=SD/mean) of DBM in AB and CB were obtained. Paired t-tests were used for comparison.

Results: Mean of DBM in AB was significantly lower than that in CB (1940±130 vs. 2822±100 mg/cm³) (p<0.001) while SD and COV were significantly higher in AB than CB for all patient CBCT images (p<0.001).

Conclusions: Only the oral bone in healthy patients was examined. Thus, it is likely that masticatory functional demand is a major factor in the regional variation of DBM parameters. Current findings suggest that clinical CBCT can be used for DBM analysis to help provide more accurate diagnosis of the health status of oral bone in patients.