Periodontal repair in dogs: effect of rhBMP-2 concentration on regeneration of alveolar bone and periodontal attachment

The objective of this study was to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) concentration on regeneration of al veolar bone and cementum, and on associated root resorption and ankylosis. Contralateral, critical size, supra-alveolar, periodontal defects were surg ically produced and immediately implanted with rhBMP-2 in an absorbable col lagen sponge (ACS) carrier in 8, young adult, male, beagle dogs, 6 animals received rhBMP-2/ACS (rhBMP-2 at 0.05, 0.10, or 0.20 mg/mL; total construct volume/ defect similar to 4.0 mt) in contralateral defects following an in complete block design. 2 animals received rhBMP-2/ACS (rhBMP-2 at 0 and 0.1 0 mg/mL) in contralateral defects (controls), The animals were euthanised a t 8 weeks post-surgery and block sections of the defects were collected for histologic and histometric analysis. Supra-alveolar periodontal defects re ceiving rhBMP-2 at 0.05, 0.10, or 0.20 mg/ml exhibited extensive alveolar r egeneration comprising 86%, 96%, and 88% of the defect height, respectively . Cementum regeneration encompassed 8%, 6%, and 8% of the defect height, re spectively. Root resorption was observed for all rhBMP-2 concentrations. An kylosis was observed in almost all teeth receiving rhBMP-2. Control defects without rhBMP-2 exhibited limited, if any, evidence of alveolar bone and c ementum regeneration, root resorption, or ankylosis. Within the selected rh BMP-2 concentration and observation interval, there appear to be no meaning ful differences in regeneration of alveolar bone and cementum. There also a ppear to be no significant differences in the incidence and extent of root resorption and ankylosis, though there may be a positive correlation with r hBMP-2 concentration.