Implant-guided vertical bone growth in the mini-pig

Objective: To attain and describe guided vertical bone regeneration around titanium (Ti) and titanium zirconium (TiZr) dental implants utilizing non-glycosylated recombinant human bone morphogenetic protein-2 (ng/rhBMP-2), biomaterial scaffolds and a scaffold retainer. Materials and methods: Thirty-two modified Straumann TE implants were partially embedded in the mandibles of eight adult mini-pigs. Pre-shaped resorbable scaffolds were placed around the implant and shielded and stabilized with a newly developed Ti custom scaffold retainer (umbrella) or wide-neck (WN) healing caps to stabilize the scaffold. Ng/rhBMP-2 (50 mu g) was applied to the supracrestal portion of the implant or incorporated within the scaffold. At 9 weeks, soft tissue healing was assessed. Vertical bone regeneration outcomes including bone height, bone-to-implant contact (BIC) and bone volume were assessed by micro-computed tomography and histology. Results: Soft tissue healing at the test sites (+ng/rhBMP-2/+scaffold) appeared to be substantially better than the control sites (-ng/rhBMP-2/-scaffold). Bone height, BIC percentage and bone volume were all similar regardless of whether WN healing caps or umbrella scaffold stabilization was used for all biomaterial scaffolds tested. WN healing cap test sites showed greater new bone height and BIC as compared with aggregate data from the control sites (P=0.05). Comparison of aggregate data from the umbrella test sites showed greater BIC and new bone volume as compared with aggregate data from the control sites(P=0.05). Conclusion: Vertical bone regeneration was successfully attained utilizing ng/rhBMP-2, biomaterial scaffolds and a scaffold retainer.