A combined synthetic cell-binding peptide(P-15)/natural mineral in critical-size defects

Objective: The purpose of this study was to histomorphometrically evaluate the synthetic peptide analog (P-15) bound to anorganic bovine mineral (ABM) in critical-size defects in the rat calvariae.

Methods: A 5mm diameter critical-size defect was prepared in 48 rat skulls and divided into four equal groups: ABM/P15 particles covered by a membrane, ABM/P15 particles uncovered, non-grafted membrane-protected, and a non-grafted uncovered control sites. At 12 weeks, the following parameters were measured histomorphometrically: area percentage of newly-formed bone and residual particles; length of the internal and external bone bridging, and regenerated marginal and central total tissue augmentation height.

Results: Non-grafted membrane-protected sites gained 60.6% of newly-formed bone, followed by 50.6%, and 44.2% (p<0.05 vs. membrane only) at the grafted covered and uncovered sites, respectively. All experimental sites contained significantly (p<0.005) more bone than control sites (19.9%). %ABM/P15 particle area fraction was similar in both types of grafted sites. Mean internal and external bone bridging at non-grafted membrane-protected sites (76.7% and 71.2%) were significantly greater (p<0.005) than that of the grafted covered particles (43.95% and 51.8%), grafted particles only (28.7% and 23.9%), and controls (28% and 25.5%), except for internal bone bridging in grafted covered particles group. Regenerated marginal and central augmentation height values (0.92mm and 1.02mm) was greatest in the grafted covered particles group, followed by non-grafted membrane-protected (0.88mm and 0.51mm), and grafted particles only (0.89mm and 0.12mm), all significantly greater (p<0.001) than controls (0.63mm and 0.04mm). Conclusion: While anorganic bovine mineral/cell-binding peptide contributes volumetrically in support and shape, membrane application significantly increases amount of bone regeneration.