Small peptide (P-15) bone substitute efficacy in a rabbit cancellous bone model.

P-15 is a synthetic 15-amino acid residue identical to the cell binding domain of type I collagen. P-15 can be adsorbed onto anorganic bovine bone mineral (ABM) and will enhance cell attachment and subsequent cell activation. Although ABM/P-15 has been studied as a bone graft substitute in the oral cavity, its use in orthopedic models has been limited. Thus, this study investigated the efficacy of ABM/P-15 treatment in a rabbit model of long bone cancellous healing. Defects were created in the distal femurs and proximal medial tibiae of rabbits and were filled with either ABMP/P-15 suspended in hydrogel, ABM alone suspended in hydrogel, hydrogel carrier alone, or no graft material. Rabbits were sacrificed at 1, 2, 4, or 8 weeks postsurgery, and the femurs and tibiae were harvested. Histomorphometric analyses indicated that defects treated with ABM/P-15 had significantly larger areas of new bone formation than the other three treatments at 2 and 8 weeks postsurgery. ABM/P-15 treated defects also had significantly more bone growth than defects left empty or filled with ABM alone at 4 weeks postsurgery. Furthermore, histological examination did not reveal acute inflammatory infiltrate cells in any of the treatment conditions. These results are consistent with the findings of ABM/P-15 use in human oral-maxillofacial studies and in large animal spine fusion models.

Clinical evaluation of the combination of anorganic bovine-derived hydroxyapatite matrix/cell-binding peptide (P-15) in particulate and hydrogel form as a bone replacement graft material in human periodontal osseous defects: 6-month reentry controlled clinical study.

BACKGROUND: This prospective, randomized, controlled clinical trial study compared the clinical outcomes of the biomaterial anorganic bovine-derived hydroxyapatite matrix/cell-binding peptide (ABM/P-15) as a biocompatible hydrogel carrier consisting of carboxymethylcellulose and glycerol or in particulate form when used as a bone replacement graft in the treatment of human periodontal infrabony defects. METHODS: Nineteen patients with advanced chronic periodontitis were recruited. All patients had at least two non-adjacent intrabony osseous defects > or = 3 mm after completion of cause-related periodontal therapy. The surgical procedures included access flaps for root instrumentation and filling the defect with ABM/P-15 in hydrogel or particulate form. Reentry access flap surgery was performed at 6 months. Changes in soft and hard tissue outcome measurements between baseline and 6 months were evaluated in all defects. RESULTS: At 6 months, no significant differences between ABM/P-15 hydrogel and ABM/P-15 particulate were demonstrated for the amount of defect fill (3.10 +/- 0.85 mm [75.0%] versus 3.09 +/- 1.11 mm [73.7%], respectively) or defect resolution (85.8% versus 81.9%). Changes in soft tissue clinical outcomes did not show significant differences between the treatments. CONCLUSION: This trial failed to demonstrate superiority of the novel ABM/P-15 hydrogel therapeutic modality over the standard ABM/ P-15 particulate graft in the treatment of intrabony periodontal defects.