Alveolar Bone Quality Changes Depending on Masticatory Functional Demands

Objectives: Masticatory loading on teeth is transmitted to alveolar bone (AB) and stimulates bone remodeling. As teeth have different functions depending on their locations at the oral anatomical sites, the types and amounts of transmitted loadings are likely to be different as well. Thus, the objective of the current study was to examine whether the functional demands of the teeth produce variations of oral bone densities as a result of site-specific bone remodeling.
Methods: After IRB approval, total of 53 clinical cone beam computerized tomography(CBCT) images were retrospectively obtained from 30 female and 23 male patients (41 to 69 years of age). Bone voxels in CBCT images were segmented from non-bone voxels. The AB regions surrounding incisors and left first premolar in the mandibular bone were digitally isolated within 1mm outside the root surface and the basal cortical bone (CB) regions were determined at 0.6mm inside the mandibular bone borders. Bone mineral density (BMD) was assessed by averaging CT attenuation values of bone voxel. Paired t-tests were performed for comparison of AB and CB mineral densities between incisors and premolars.
Results: The BMD value of AB of the incisors was significantly higher than that of the premolars (p<0.001) while BMD values of the two CB regions were not significantly different (p=0.08).
Conclusions: The current findings indicate that oral bone develops to adapt masticatory functional demands at different anatomical sites. The higher BMD values of smaller sized incisor regions than larger sized premolar regions can be helpful in maintaining the stability of incisors under masticatory loading. The BMD differences were found only at the AB regions suggesting that the effect of masticatory loading is limited to the local bone region adjacent to teeth.