Histomorphometric Evaluation of Bone Formation in Peri-Implant Defects Treated With Different Regeneration Techniques: An Experimental Study in a Rabbit Model

PurposeThe aim of this study was to investigate the healing of artificially created peri-implant circumferential bone defects using three bone-regeneration techniques.Materials and MethodsRabbit tibias (24 rabbits), in which bone defects (9-mm diameter, 4-mm depth) were created and implant beds (3-mm diameter, 6-mm depth) were prepared in the middle of the created defects, were used as the experimental model. Dental implants (3.0 × 10 mm) were inserted, and the peri-implant bone defects were grafted with demineralized freeze-dried bone allograft (DFDBA) plus saline solution, DFDBA plus platelet-rich fibrin (PRF), or DFDBA plus rifamycin. After 4 weeks, the animals were euthanized and the implants with surrounding bone were removed. Undecalcified histomorphometric examinations with toluidine blue staining were performed, and the bone-to-implant contact (BIC) and percentage of new bone formation were evaluated.ResultsThe BIC was 50.94% ± 24.39% in the DFDBA–plus–saline solution group, 60.07% ± 4.91% in the DFDBA-plus-rifamycin group, and 73.43% ± 3.86% in the DFDBA-plus-PRF group. The percentage of new bone formation at the defect area was 37.61% ± 1.70% in the DFDBA–plus–saline solution group, 48.51% ± 2.80% in the DFDBA-plus-rifamycin group, and 63.09% ± 2.10% in the DFDBA-plus-PRF group. In terms of new bone formation and BIC, the DFDBA-plus-PRF and DFDBA-plus-rifamycin groups were significantly different from the DFDBA–plus–saline solution group. The difference between the DFDBA-plus-PRF and DFDBA-plus-rifamycin groups was also statistically significant.ConclusionsThe addition of PRF or rifamycin to DFDBA had a significant positive effect on bone healing in peri-implant bone defects. The DFDBA-plus-PRF group showed the highest percentages of new bone formation and BIC.