Alveolar Ridge Conservation by Early Bone Formation After Tooth Extraction in Rabbits. A Histomorphological Study

Alveolar ridge volume loss is an irreversible process. To prevent this physiological event, which typically result in significant local anatomical changes in both the horizontal and the vertical dimension, some strategies are indicated to minimize the loss of ridge volume that typically follows tooth extraction. The purpose of this study was to evaluate if three different bone grafts could promote new bone formation in the alveolar socket following tooth extraction for the alveolar ridge conservation. First mandibular molars of male adults rabbits were extracted and the extraction sockets were randomly treated with three different bone grafts, one xenograft and two alloplastic grafts, and a group that received no treatment (blood clot). The extraction sockets of selected rabbits from each group were evaluated at 4, 6, or 8-week post-extraction. The results indicated that the extraction sockets treated with alloplastic graft (biphasic calcium phosphate) exhibited lamellar bone formation (6.5%) as early as four weeks after the extraction was performed. Moreover, the degree of new bone formation was significantly higher (P<0.05) in the extraction sockets treated with biphasic calcium phosphate at 8-week post-extraction than that in the other study groups. In this study, we demonstrated that the proposed animal model is useful to evaluate the bone formation after tooth extraction and the alveolar ridge conservation is feasible. The new bone formation and alveolar ridge preservation with bone graft after extraction of molar teeth, could result in the maintenance of sufficient bone volume to place an implant in an ideal restorative position without the need for ancillary implant site development procedures.