Effect of PDGF‐BB and beta‐tricalcium phosphate (β‐TCP) on bone formation around dental implants: a pilot study in sheep

Abstract

The aim of this investigation was to examine the effect of a combination of purified recombinant human platelet-derived growth factor (rhPDGF-BB) mixed with a synthetic beta-tricalcium phosphate (β-TCP) on bone healing around dental implants with critical size circumferential defects. Three critical size circumferential defects were prepared in the ilium of six sheep. Three dental implants were placed into the centre of each defect and the 3.25mm circumferential gap was filled with (a) blood clot alone; (b) β-TCP; (c) rhPDGF-BB (0.3mg/ml) with β-TCP. All the defects in each group were covered with a Bio-Gide(®) resorbable barrier membrane. The sheep were sacrificed at 2 and 4weeks and histological and histomorphometric analyses were performed to determine the percentage of new mineralized bone formation and residual β-TCP graft particles in the defects. Defects filled with rhPDGF-BB/β-TCP showed the highest rate of bone formation after 2 and 4weeks with limited degradation of the β-TCP particles over 4weeks. Defects filled with β-TCP showed the least bone fill after 2 and 4weeks, and faster degradation of the β-TCP particles over 4weeks compared with defects filled with rhPDGF-BB/β-TCP. Percentage of new mineralized bone was comparable in defects to blood clot alone and β-TCP after 4weeks of healing, but there was a collapse in the defect area in defects with blood clot alone. In comparison, the space was maintained when β-TCP was used in defects at 4weeks. Defects which had β-TCP alone showed an inhibition in bone healing at 2 and 4weeks; however, the combination of rhPDGF-BB with β-TCP enhanced bone regeneration in these peri-implant bone defects at the same time intervals.