LAUSR

AIM To investigate the immunohistochemical characteristics of a highly porous synthetic bone substitute and a cross-linked collagen membrane for guided bone regeneration. METHODS Three experimental groups were randomly allocated at chronic peri-implant dehiscence defect in 8 beagle dogs: (i) biphasic calcium phosphate covered by a cross-linked collagen membrane (test group), (ii) deproteinized bovine bone mineral covered by a natural collagen membrane (positive control), and (iii) no treatment (negative control). After 8 and 16 weeks of submerged healing, dissected tissue block were processed for immunohistochemical analysis. Seven antibodies were used to detect the remaining osteogenic and angiogenic potential, and quantitative immunohistochemical analysis was done by software. RESULTS The antigen reactivity of alkaline phosphatase was significantly higher in the test group compared to the positive and negative controls, and it maintained till 16 weeks. The intensity of osteocalcin was significantly higher in the positive control at 8 weeks than the other groups, but significantly decreased at 16 weeks and no difference was found between the groups. A significant large number of TRAP-positive cells were observed in the test group mainly around the remaining particles at 16 weeks. The angiogenic potential was comparable between the groups showing no difference in the expression of transglutaminase II and vascular endothelial growth factor. CONCLUSION Guided bone regeneration combining a highly porous biphasic calcium phosphate synthetic biomaterial with a crosslinked collagen membrane, resulted in extended osteogenic potential, when compared with to the combination of deproteinized bovine bone mineral and a native collagen membrane.