Inorganic polyphosphate adsorbed onto hydroxyapatite for guided bone regeneration: an animal study.

Inorganic polyphosphate (poly(P)) is recognized as a therapeutic agent that promotes fibroblast growth factor and enhances osteogenic differentiation, and in vivo, when adsorbed onto interconnected porous calcium hydroxyapatite (IP-CHA) enhances bone regeneration. The present study focused on the effect of poly(P) adsorbed onto IP-CHA granules (Poly(P)/IP-CHA) in guided bone regeneration (GBR). Dental implants were placed into the edentulous mandibular areas of five Beagle-Labrador hybrid dogs with screw expose on the buccal side, and then bone defects were filled Poly(P)/IP-CHA (test) or IP-CHA (control). After 12 weeks, histological evaluation and histomorphometrical analysis were performed. Newly-bone formation around exposed implant screw was clearly detected in the test-group. The ratio for regenerated bone height in the test group versus the control-group was 85.6±20.2 and 62.6±23.8, respectively, with no significant difference, while, that for bone implant contact was significantly higher (67.9±11.8 and 48.8±14.1, respectively). These findings indicate that Poly(P)/IP-CHA enhances bone regeneration in GBR.

Initial bone regeneration around fenestrated implants in Beagle dogs using basic fibroblast growth factor-gelatin hydrogel complex with varying biodegradation rates.

PURPOSE: The purpose of this study was to compare the effectiveness of fast and slow biodegradation of basic fibroblast growth factor (bFGF)-gelatin hydrogel complex on bone regeneration around fenestrated implants as a new augmentation drug delivery system. METHODS: Nine titanium implants (3.3mm diameter and 10mm length) were placed into the edentulous areas of the mandibles of three adult beagle dogs with four screws exposed at the upper buccal side. The effectiveness of bFGF-gelatin hydrogel complexes of varying degradation types used to cover implant screws without membrane were compared with 1 microg and 10 microg bFGF-98 wt% gelatin as the fast degradation type and 10 microg bFGF-95 wt% gelatin as the slow degradation type. After 4 weeks, bone regeneration around the screws was evaluated histologically and histomorphometrically. RESULTS: With use of 10 microg bFGF, regenerated bone around exposed screws was clearly seen in both the fast and slow degradation type groups. In contrast, little bone formation was seen in the fast degradation-type group with 1 microg bFGF. Height of regenerated bone for the slow degradation-type complex group was significantly greater than for the fast degradation-type group with 1 microg bFGF (P<0.05). CONCLUSION: These results suggest that use of slow degradation-type bFGF-gelatin hydrogel complex may accelerate bone regeneration around fenestrated implants at an early stage of bone regeneration.