Osseointegration of Dental Implants Placed into Canine Mandibular Bone Regenerated by Bone Transport Distraction Osteogenesis

Purpose: The purpose of this study was to compare the osseointegration of dental implants placed in canine mandibular bone and in regenerated bone produced by bone transport distraction osteogenesis. Materials and Methods: Ten adult foxhounds were divided into two groups of five animals each. In all animals, a 40-mm defect was created on one side of the mandible. A bone transport reconstruction plate was used to stabilize the mandible and regenerate bone. Six weeks after the distraction period was finished, dental implants were placed in regenerated and native mandibular bone. The animals were sacrificed after another 6 and 12 weeks of healing, respectively. Results: Microcomputed tomographic evaluation showed that bone volume fraction (BV/TV) was greater at the coronal regions of the implants and decreased toward the apical regions. There was an increase in BV/TV around implants placed in regenerated bone from 6 to 12 weeks of healing. The regenerated group showed lower BV/TV at 6 weeks versus implants placed in native bone but had reached the same levels as the native bone at 12 weeks. Histology showed that direct bone-to-implant contact was greater for implants placed in native bone than for those placed in regenerated bone for both time periods. The removal torque of the implants placed in native bone was higher at 6 weeks than that of implants placed in regenerated bone. At 12 weeks, there were no statistically significant differences in removal torque between the groups. Conclusions: Bone was successfully regenerated in all animals. The implants placed entirely in regenerated bone were osseointegrated. The regenerated bone around the implants became denser over time. This finding suggests that implants placed entirely in regenerated bone will be as well integrated as implants in native mandibular bone by 12 weeks after placement.