Bone morphogenetic protein-2 incorporated calcium phosphate graft promotes peri-implant bone defect healing in dogs: A pilot study

Objectives: The evaluation of three different drug delivery modes of bone morphogenetic protein-2 (BMP-2) in healing peri-implant bone defects in beagle dogs. BMP-2 was incorporated in or onto calcium phosphate (CaP) granules in various ways: (i) directly on the outer layer of granules CaP: as an adsorbed depot; (ii) during the entire precipitation process of CaP: an internally incorporated depot; or (iii) during the biomimetic coating precipitation of BMP-2 on the surface of CaP granules: as a coating incorporated depot. Material and Methods: After extraction of the lower molars and wound healing in 6 male beagle dogs, 36 implants were placed (n = 6 animal per group). Peri-implant bone defects were induced. The following treatment groups were evaluated: no treatment; air abrasive surface cleaning (SC) using hydroxyapatite; SC and the subsequent filling of the defect with CaP without BMP-2; SC plus the subsequent filling of the defect with CaP adsorbed BMP-2; SC plus the subsequent filling of the defect with CaP internally incorporated BMP-2; SC plus the subsequent filling of the defect with CaP coating incorporated BMP-2. Histological and histomorphometric analyses were carried out to quantify and compare the changes in bone tissue surrounding the treated implants. Results: In Group 1 with no treatment, four implants were lost. Group 5 with the SC and the subsequent filling of the defect with internally incorporated BMP-2 biomimetically prepared CaP (BioCaP), whereby the BMP-2 is incorporated in the entire volume of all BioCaP particles, showed overall the best results to regenerate bone around the implants. Conclusion: This study concluded that the group treated with SC plus the subsequent filling of the defect with CaP BMP-2 internally incorporated BMP-2, whereby BMP-2 has been incorporated in the entire volume of all CaP particles, showed overall the best results when aiming to regenerate bone around the implants.