Bone morphogenetic protein-2 for peri-implant bone regeneration and osseointegration

Recombinant human bone morphogenetic protein-2 (rhBMP-2) induced bone regeneration and osseointegration was evaluated in supraalveolar peri-implant defects in 5 beagle dogs. Alveolar bone was reduced 5 mm in height in mandibular premolar areas and the premolars were extracted. Three 10 mm titanium fixtures were placed 5 mm into each reduced alveolar crest, leaving 5 mm in a supraalveolar position. Alternate quadrants in consecutive animals received a surgical implant consisting of 2 ml rhBMP-2 (0.43 mg/ml) in a type I bovine collagen carrier, or the carrier alone (control). Fixtures and surgical implants were submerged under the gingival flaps. The healing interval was 16 weeks. Histometric and radiographic evaluations were made. Defect height averaged (±SD) 5.3±0.2 and 5.1±0.2 mm for rhBMP-2 and control defects, respectively (P>0.05, n=5, paired, t-test) Bone regeneration (height) averaged 4.2±1.0 and 0.5±0.3 mm for rhBMP-2 and control defects, respectively (P<0.05). Bone regeneration (area) averaged 6.1±6.3 and 0.2±0.2 mm² for rhBMP-2 and control defects, respectively (P>0.05). Osseointegration within the confines of the defect averaged 19.1±10.1% and 8.2±4.6% for rhBMP-2 and control defects, respectively (P>0.05). Osseointegration within regenerated bone averaged 29.1±9.8% and 65.3±15.3% for rhBMP-2 and control defects, respectively (P<0.05). Osseointegration within the retained alveolar bone averaged 67.1±4.6% and 68.1±3.6% for rhBMP-2 and control defects, respectively (P>0.05). The results suggest that there is a potential for rhBMP-2 induced bone regeneration and osseointegration in surgical peri-implant defects.