Differences in static cortical bone remodeling parameters in human mandible and iliac crest.

Knowledge of the baseline turnover characteristics, and of possible general and local factors influencing alveolar bone responses, is particularly important in the planning of oral rehabilitation. The conventional tool used to obtain information on bone turnover is the iliac crest biopsy, but it is not clear whether it mirrors the situation involving the jaws. The aim of this study was to compare static bone remodeling parameters in the mandible and in the iliac crest to obtain baseline values for the mandible and to test the hypothesis of site specificity of bone remodeling. Bone specimens were obtained from 50 subjects (mean age 64 +/- 17) at autopsy. Three sites were sampled: iliac crest; jaw angle; and foramen mentalis area. In addition, occlusal status was recorded. On undecalcified thin sections, cortical porosity (Ct.Po), eroded sites (ESi), formative sites (FSi), osteonal diameter (On.Dm), Haversian canal diameter (H.Ca.Dm), and wall width (W.Wi) were measured. Ct.Po in the jaw angle and in the foramen mentalis area was lower (48% and 50%, respectively) than in the iliac crest, as was ESi and FSi (80% in the jaw angle and 74% in the foramen mentalis area). In the foramen mentalis area, Ct.Po was greater in subjects with occlusion. On.Dm, H.Ca.Dm, and W.Wi were significantly larger and mutually correlated within the mandible, whereas no correlation was found between mandibular sites and iliac crest. Static cortical bone remodeling parameters are different in the mandible and the iliac crest, thus confirming the hypothesis of site specificity of bone remodeling. Within the mandible, the parameters were correlated, whereas there was no correlation between the mandible and the iliac crest. This could be ascribed to the different functional demands to the mandible and the iliac crest, which was also reflected in the observed influence of functional occlusion on bone remodeling in the mandible. It can thus be concluded that bone reaction to dental intervention is more dependent on the local environment than on general bone turnover as reflected by the iliac crest.