Boosting effect of bisphosphonates on osteoconductive materials: a histologic in vivo evaluation

Abstract

The effect on bone regeneration, of adding pamidronate disodium to bovine-derived hydroxyapatite, was histologically evaluated, using the sheep bone model. Twenty-four intrabony defects were prepared in the lower jaw of eight sheep using trephine 6 mm burs. One cavity was left unfilled and the other two were filled with bovine-derived hydroxyapatite (BioOss) alone (control group) or with bovine-derived hydroxyapatite mixed with pamidronate disodium (Aredia) (case group), respectively. After 6 wk, the animals were killed and the coded samples observed using an optical microscope. The percentage of regenerated bone, number of osteoclasts and amount of inflammation was recorded. Statistical analysis was carried out using chi-square and Mann-Whitney U-tests. The results manifested a significant difference in the amount of bone formation, with the most being observed in the case group and the least in the negative-control group (p<0.001). Significantly fewer osteoclasts were observed in the case group than in the other groups (p<0.001). The amount of inflammation did not seem to differ within the case and control groups (p>0.05). Adding pamidronate disodium to bovine-derived hydroxyapatite improves its osteoconductive and regenerative specifications. Further study should determine the systemic effects of a single local administration of these drugs, and their appropriate dose and type, with minimal risk.