| Dental implants had been used widely in the dental clinical therapy. But due to congenital abnormality, trauma, tumor and inflammation, bone defects in maxillofacial region is very common. The repair of peri-implants bone defects is a significant problem faced by oral and maxillofacial surgeons. In these cases, bone grafting is usually needed. Therefore a lot of scholars devote themselves to the experimental and clinical study of bone defect reconstruction. The material for repair of peri-implants bone defect become the hot topic of researches in recent years.Alternative solutions include implantation of the defect site with autografts , allografts of bone tissue, or other resorbable biomaterials. Autograft bone harvest encounters problems with the added surgical time, limited supply and morbidity of the donor site; allografts spark an immune reaction; and bone substitutes are solely osteoconductive matrices, not bioactive materials, generally act as a matrix for new osseous ingrowth and creeping substitution.Osteoinduction active material (OAM) was prepared by defatted and decalcified bone xenograft as a carrier combined with bone morphogenetic protein (BMP). It has good biocompatibility and nice bone conductive and inductive capability. OAM is much efficient in releasing BMP and also has satisfied mechanical strength, and could effectively induce bone tissue regeneration.ObjectiveThe purpose of this study is to use OAM to treat peri-implants bone defects by animal experiment and to investigate the new bone formation; to explore the potential of using OAM for the reconstruction of peri-implants bone defects; to provide theoretical evidence and experimental information for the clinical application.MethodsFour male adult Beagle canines, with an average weight of about 10-12kg underwent extraction of the mandible first, second and fourth premolar to create edentulous regions. 4 groups were divided. Experimental group A: titanium implant + 0AM /PRP; Experimental group B: titanium implant + TCP / PRP; Experimental group C: titanium implant + 0AM; Control group: titanium implant + TCP. Three months after healing, four titanium implants (3.3mm in diameter and 8.0mm in length) were inserted in each mandible. Peri-implants bone defects (1mm in width, 4.0mm in depth) were created. Then the defects were repaired with above four materials. Animals were respectively sacrificed at the end of 8 weeks and 16 weeks. Then the specimens were made for anatomy observation, histological section, scanning electric microscope observation and energy disperse analysis of element Ca and P. New bone regeneration in bone-implant interface were analyzed.ResultsOAM could effectively accelerate the reconstruction of peri-implants bone defects, the amount of new bone increased as time elapsed. The results observed by light microscopy showed as follows: at 8 weeks after surgery, in the experimental group , a number of new bones formed and enlarged and grew into hollow screw, some part of implants were directly contacted with new bone; at 16 weeks following the operation, new bone formed much and were further mature. There was good osseointegration between the bone and implant in experimental groups and there was fiber connect in control group. In the experimental group A, new bone formed earlier, much, and were further mature, excellent healing results were showed including the quantity and quality of newly regenerated bone.ConclusionsOAM has good biocompatibility and also has nice bone conductive and inductive capability. It could effectively accelerate the reconstruction of peri-implant bone defects and improve the osseointegration in the interface between the titanium implant and new bone. Is a kind of bone substitute material with a potential for clinical application.
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