Effects of low-dose rhBMP-2 on peri-implant ridge augmentation in a canine model.

Abstract

The aim of this study was to investigate the potential of low-dose rhBMP-2 combined with Hydroxyapatite (HAp)/β-tricalcium phosphate (TCP)/ Collagen (Col) composite in repairing the peri-implant critical size defect and to determine the optimal rhBMP-2 concentration. Fifty saddle-type alveolar defects (10mm mesiodistally and 4mm apicocoronally) were surgically prepared on edentulous ridges in ten beagle dogs. Following implant placement, the defects with vertically exposed implant fixtures either received (a) no graft, (b) HAp/TCP/Col composite, (c) HAp/TCP/Col +0.02mg/ml rhBMP-2, (d) HAp/TCP/Col +0.08mg/ml rhBMP-2 or (e) HAp/TCP/Col +0.2mg/ml rhBMP-2. After healing for 4 or 8weeks, bone regeneration and mineralization were assessed through radiography, micro-CT, fluorescence labelling and histologic analyses. Implant stability was measured through resonance frequency analysis. It was evident HAp/TCP/Col with 0.2mg/ml rhBMP-2 manifested strong osteogenic potential in this large animal model, as significantly more and faster new bone formation with better implant stability was identified compared to the HAp/TCP/Col-alone control group (adjusted p<.05). Our results highlight the constructs of HAp/TCP/Col +0.2mg/ml rhBMP-2 without barrier membranes as a promising tool for peri-implant ridge augmentation.