Bone regeneration around fenestrated implants by different bFGF-gelatin hydrogel complexes

Objectives: This study was designed to examine the effectiveness of different absorption types of basic fibroblast growth factor (bFGF) - gelatin hydrogel complex on bone regeneration around fenestrated implants.

Methods: Early absorption type of bFGF - 98wt% gelatin hydrogel complex and late absorption type of bFGF - 95wt% gelatin hydrogel complex were used as a drug delivery system for bone regeneration around experimentally induced exposed screws of the implant. These complexes possessed bFGF contents of 1 and 10 µg (A: bFGF 1 µg - 98wt% gelatin, B: bFGF 10 µg - 98wt% gelatin, C: bFGF 10 µg - 95wt% gelatin). Edentulous areas were prepared by extracting all lower premolars of three male dogs. After three months, three bone sockets on each side of the edentulous mandible were prepared for implant placement (D: 3.3×10 mm, Brånemark MkIII®, Nobel Biocare). Bone defect (3×4 mm) at buccal side of each socket was made to expose upper four screws of the implant. After implant placement, A, B and C complexes were filled randomly to cover all four screws. After 4 weeks, bone regeneration around fenestrated implants was evaluated histologically and histomorphometrically as height of regenerated bone.

Results: Histologically, regarding exposed screws, in the groups of A and B, poor bone regeneration was observed. In contrast, in the group of C, exposed screws were fully covered by newly formed bone. Histomorphometrically, height of regenerated bone in the group of C (2.36±0.29 mm) was shown to be significantly higher than that of the group of A (1.55±0.37 mm)(p<0.05).

Conclusion: Within the limited results of this study, it is suggested that late absorption type of bFGF 10 µg - 95wt% gelatin complex may be effective on bone regeneration around fenestrated implants.