Efeito do uso combinado de bisfosfonato e enxerto xenógeno na reparação óssea alveolar : estudo histomorfométrico

Abstract

Bisphosphonates have been associated with medication-related osteonecrosis of the jaw (MRONJ), a disorder that has some risk factors such as surgical interventions in the jaw bones, especially tooth extractions. On the other hand, xenogeneic grafts have been widely used to fill the alveolar socket after tooth extraction, with clinical evidences of improving local conditions of the surgical bed for oral rehabilitation. The aim of this study was to investigate the effect of combined bisphosphonate and the xenogeneic graft Bio-Oss® Collagen on alveolar bone repair after tooth extraction. Sixty rats were allocated into five groups according to the treatment received: zoledronic acid (group 1) and alendronate (group 2) both with xenogeneic graft; zoledronic acid (group 3) and alendronate (group 4) both without xenogeneic graft; and control (group 5). All animals were subjected to tooth extractions, and maxillae were dissected and macro- and microscopically analyzed. Frequency of oral mucosal wounds did not significantly differ between the groups; however, these lesions were significantly smaller in the control group. The amount of fibrous connective tissue was greater in groups 2 (alendronate/Bio-Oss) and 5 (control) than in 3 (zoledronic acid) and 4 (alendronate). Group 4 showed greater amounts of vital bone than did groups 1 (zoledronic acid/Bio-Oss), 3 and 5. The amounts of non-vital bone were greater in the zoledronic acid groups (1 and 3), where non-vital bone was less in group 1 than 3. Group 3 showed more inflammatory infiltrate than groups 2, 4 and 5. There were greater amounts of microbial colonies in group 3. Inflammatory infiltrate and microbial colonies were negatively correlated to vital bone and positively correlated to non-vital bone. Inflammatory infiltrate and microbial colonies were positively correlated to each other. Conclusion: Post-extraction socket filling with Bio-Oss® Collagen did not prevent the occurrence of non-vital bone and infection, but it did lower the extent of these variables in rats under treatment with zoledronic acid.