Effects of occlusal loading on alveolar bone remodeling and changes in the distribution of neuropeptides after tooth replantation in rats.

Biomechanical and biochemical factors are involved in bone remodeling. Occlusal loading is a well-known mechanical modulator of alveolar bone remodeling. Neuropeptides, such as vasoactive intestinal peptide (VIP) and calcitonin generelated peptide (CGRP), have been described within the biochemical bone regulators. In this study, the influences of occlusal loading on the alveolar bone remodeling and the distribution of VIP- and CGRP-immunoreactive (IR) fibers were investigated 1, 3 and 5 days after tooth replantation in rats. At day 5, occlusal loading induced a significant increase (p<0.05) in osteoclast number and osteoblast surface compared to those in the nonoccluded group. VIP-IR fibers were observed beside osteoblastic layers and their distribution was significantly enhanced (p<0.05) at day 5 in the occluded group, compared to the non-occluded group. Although there was immunoreactivity for CGRP in the periodontal ligament and alveolar bone apically, CGRP-IR fibers were not detected above the furcation. These results suggest that, after tooth replantation in rats, occlusal loading induced an increase in osteoclast and osteoblast formation, and that VIP might play a functional role in osteoblasts.