Experimental Study On OSTEON In Repairing The Mandible Defect Of Dogs

IntroductionUtilizing the implant denture to repair the deletion teeth can not only offer an ideal and reasonable support and retention, but also have some advantages such as beautiful outlook, comfort, need not to utilize or cut the abutment. Furthermore, the implant denture provide a new choice to some patients who can not tolerance active dentures or can not repair with traditional dentures after tumor surgery. But due to congenital abnormality, trauma, tumor and inflammation, bone defects in dental implant region is very common, which limits the serviceable range of the implant denture, and have became a significant problem faced by oral and maxillofacial surgeons. So many researchers utilize many kinds of bone replacement materials and technique to repair the bone defect in dental implant region, and to recover the height and the fullness of the alveolar bone one after another, with a purpose to improve the long-term achievement ratio of the dental implant and to win a desirable aesthetics result.Alternative solutions include implantation of the defect site with Autografts, Allografts, Xenografts or bone replacement materials. All of the materials have sloved the problem of repairing the bone defect, but also, they all have their advantages and disadvantages. Autograft bone harvest encounters problems with the added surgical time, limited supply and morbidity of the donor site; Allografts and Xenografts spark an immune reaction; and bone replacement materials are solely osteoconductive matrices, not bioactive materials, generally act as a matrix for new osseous ingrowth and creeping substitution. The materials which applied in this experiment are OSTEON and osteoinduction active material (OAM), both of which are composite materials.OSTEON is a synthetic osteoconductive bone graft subsititute composed of hydroxylapatite (HA) and beta-tricalcium phosphate (β-TCP). OSTEON presents an interconnected porous structure, similar to that of human cancellous bone. It has good biocompatibility and nice tensiometric property, so it could effectively induce bone tissue regeneration, although it doesn't have efficiently inductive capability.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.ObjectiveOAM, which is made in China, has been used in our division many years and have obtained nice praise. On the other side, OSTEON is a fresh introduced materials from Korea, and have never been used internal. The purpose of this study is to investigate the potential of using OSTEON to guide bone regeneration and repair the mandible bone defects; and then to provide theoretical evidence and experimental information for the clinical application by using OSTEON and OAM to repair the mandible defects by animal experiment.Metheods1. The establishment of animal models4 healthy adult dogs were used in the experiment, falling into two groups. Each one was chosen three sites on its caudomedial part of the hemi-mandible body. Each site was been implanted with OAM, or OSTEON, or only without any materials implanting just as a blank randomly.2. To draw the materials from dogs It was have to make an intramuscular with tetracycline hydrochloride (25mg/kg) 10 days and 3 days before drawing the materials. One group killed the animals after three months of the operation, and the other group did that after six months.3. Slicer makingGradient alcohol dehydration, embedded in methyl methacrylate, slice by Lecia-1600 slicer, selected the middle section for fluorescence microscopy, HE staining and toluidine blue staining.4. ObservationSpecimens obtained were evaluated with general observation, X-ray observation, fluorescence microscopy observation to mark the new bone formation with tetracycline, optical microscope observation to identify the osteogenesis status, and chose different multiple photographed.5. Computer image analysisThe rate of fluorescence labeling and bone mineralization apposition rate (MAR) were calculated via the fluorescence microscopy observation and the Metamorph Imaging System V4.6 image analysis software. And use the SPSS 13.0 software to carry out statistical analysis.ResultsFour dogs were all in good health, and the wounds all achieved the primary healing. General observation and stereoscopic microscope showed that new bone formation either could be found around and inside OSTEON, or that of OAM. Optical microscope observation showed that the two stuffs had no adverse effects to the process of recovery of bone. The rate of fluorescence labeling and bone mineralization apposition rate (MAR) of OSTEON are higher than that of OAM at 3 months, but they have no significant differences at 6 months after statistics calculation. And the blank had merely little display via the fluorescence microscopy observation. ConclusionOSTEON can better repair bone defects after 3 months, in terms of the quantity of new bone and the bone formation rate are significantly better than OAM.