Bone Mineral Density Distribution in Mandibular Incisors Region

Objectives: The primary function of incisors is cutting and shearing. We hypothesize that bone surrounding incisors may adapt to maintain the specific masticatory force. Thus, the objective of this study was to examine the quantitative pattern of bone mineral density (BMD) surrounding the mandibular central incisors.
Methods: Following approved IRB, clinical cone beam CT (CBCT) images (300 µm voxel size) obtained from 10 patients (4 male and 6 female, 61 to 70 years of age) were used to digitally cut bone surrounding 2 mandibular central incisors. After teeth were extracted, bone voxel were segmented from non-bone voxels. Three-dimensional layer of bone with one voxel thickness was isolated from the teeth socket to the periosteal direction. A total of 56 to 60 layers were collected. A histogram of grey level, which is proportional to BMD, was obtained from each layer to measure its mean, standard deviation (SD), fifth percentile low (Low₅) and high (High₅). Paired t-tests were performed for layer by layer comparisons within the same patient image.
Results: The mean, SD, and High₅ values of BMD rapidly increased up to 2.4 mm (layer 8) away from the teeth socket (p<0.05).
Conclusions: The current findings indicate that the masticatory force influences BMD at the local region surrounding mandibular central incisors. Active bone remodeling triggered by masticatory force likely results in the rapid BMD changes. The heterogeneous BMD distribution provides useful baseline data to make a better treatment plan for oral bone complication.