Associations of bone mineral densities between cervical vertebrae and mandibles

Objectives: Vertebral bone mineral density has been widely utilized to assess age-related bone disease in orthopedic clinical settings, while its relationship with dental bone mineral density has not been fully investigated. Thus, the objective of this study was to examine associations between cervical vertebral (C2 and C3) and mandibular bone mineral densities measured using 3D cone beam computed tomography (CBCT) of dental patients.
Methods: Following IRB approval, CBCT images taken from 44 patients (16 males and 28 females, 40 to 60 years) were retrospectively obtained. A heuristic algorithm was used to segment bone voxels in CBCT images from non-bone voxels. Then, the C2 and C3 vertebrates were digitally isolated by removing posterior processes at 10 voxels from either side of vertebral endplate remaining only vertebral body. Alveolar bone (AB) and basal control bone (CB) regions of left mandibular canine and first premolar were digitally determined within 1mm outside root surface and at 0.6 mm inside mandibular bone borders, respectively. Histogram of CT attenuation values for those bone voxels, which are proportional to mineral contents, was used to assess mean, fifth percentile of low and high attenuation values (low₅ and high₅). Pearson correlation tests between the CT attenuation values were conducted with p<0.05.
Results: Values of mean, low₅ and high₅ of cervical vertebrates (C2 and C3) have significant positive correlation with those of corresponding parameters of alveolar and basal cortical mandibular bone (r = 0.725 to 0.312, p < 0.039).
Conclusions: The significant association of bone mineral density between cervical vertebrae and mandibular bone gives an insight that the age related bone disease can systemically influence oral bone as well as vertebral bone. This finding provides more information to understand a mechanism involved in oral bone osteoporosis.