Biological response to ß-tricalcium phosphate/calcium sulfate synthetic graft material: an experimental study.

PURPOSE: The aim of this study was to evaluate the effect of a biphasic synthetic bone graft material composed of ß-tricalcium phosphate (ß-TCP) and calcium sulfate (CS) in 12 New Zealand rabbits. MATERIALS AND METHODS: A circular bicortical critical-size cranial defect was created in each of 12 rabbits. The defects were grafted with ß-TCP/CS. Animals were euthanized at 3 and 6 weeks. Harvested tissue specimens were evaluated histologically and histomorphometrically. Parameters associated with new bone formation and graft resorption were measured and calculated. The results were statistically analyzed using the Mann-Whitney test. RESULTS: Our data demonstrated the biocompatibility of synthetic ß-TCP/CS, as no inflammatory response was observed, and no fibrosis was developed between the graft particles and the newly formed bone. Moreover, ß-TCP/CS acted as an osteoconductive scaffold that allowed a significant bone regeneration and graft biodegradation with time. CONCLUSION: In this animal model, synthetic ß-TCP/CS proved to be a biocompatible, osteoconductive, and bioresorbable bone graft substitute.

Experimental study of the effect of autologous platelet-rich plasma on the early phases of osteoinduction by allogenic demineralized bone matrix.

PURPOSE: To evaluate the effect of autologous platelet-rich plasma (PRP) on the early phases of osteoinduction by allogenic demineralized bone matrix (DBM) in rabbit intramuscular positions. MATERIALS AND METHODS: Allogenic DBM was produced from bones of 3 healthy rabbits. In each of 6 experimental animals, 0.3 mL autologous PRP was prepared and 2 muscle pouches were created, where 250 mg DBM + PRP (experimental sites) and 250 mg DBM without PRP (control sites) were randomly implanted. Animals were euthanized 3 weeks postoperatively. RESULTS: Histologic examination revealed uneventful healing in all cases, whereas remineralization of the periphery of the bone graft particles was a constant finding. In both control and experimental sites, fibroblasts and other mesenchymal cells (probably osteoprogenitor cells and preosteoblasts) were observed. The main histological difference was the recolonization of the empty lacunae of the bone graft particles by osteocytes at the control sites. The degradation of the graft at the control sites was statistically significantly quicker, although a statistically significant difference regarding the amount of the newly formed fibrous connective tissue was not observed. CONCLUSION: The present study demonstrated that in this experimental model, the addition of PRP to DBM had a negative effect on the early phases of osteoinduction at 3 weeks of observation.