Experimental Study Of Pure-phase β-tricalciuphosphate In Repairing Bone Defects Of Immediate Implantation

The success of dental implant depend on the using of bonesubstitute material and biomembrane in great extent. Thedevelopment of material improved the character of bonesubstitute material, material with better bio-compatibility,ideal degradation time ,and can meet the needof biomechanics is expected by dental implant sugery.β-tricalcium-phosphate(β-TCP) has an broad foreground instudy and exploiture.The bone substitute material in this study we used isCERASORB, a resorbable phase-pure synthetic β-TCP .It iswidely used in periodontal disease ,sinus floor elevationand retain the bone height after exodintia ,but we haven'tfound it used in the studies of repairing bone defects ofimmediate implantation.The aim of our study is to evaluate the osteogenesischaracter of pure-phaseβ-tricalcium phosphate (Cerasorb)and autogenous bone graft in repairing segmental bonedefects of immediate implantation , to explore thepossibility of Tricalcium phosphate can be used in therepair of bone defects of dental implant,and give a theorybasis for clinical use in the future.In this study,a screw shaped titanium implant was placedin the distal metaphysis of the femurs of rabbits simulatingimmediate implanting model,a segmental defects(2x2x3mm) indistal metaphysis,then the defects were repaired withβ-Tricalcium phosphate(TCP) in experiment group and withautogenous bone in contrast group. The osteogenesis in thedefect area and the change of marterial structure and therelations of new bone with implant were observed by X -rayand histological examination.Pure – phase β-tricalcium phosphate(Cerasorb)wascapable of healing the defects of immediate dental implantin large part by 120 days,(the structure changed a lot andpart of the material was absorbed.) New bone combined withimplant more early(30days).By histological examinations, many osteogenic cellswere observed ,bone trabeculae have already formed andsurround the Cerasorb granules as well as the osteoid bands.60 days post operation, osteocytes and bone trabeculae werefound in the granules. Osteoblast were not found in the bonedefect.Generally,autologoues cancellous bone is used to fillbone defect around dental implant,but in the present casesthe artifical bone material β-TCP was highly efficaciousin facilitating the bone remodeling , as shown by thefollow-up X-rays,substantiality microscope.The use ofartificial bone eliminates the need for additional surgicalinvasion associated with the harvesting of autologouscancellous bone,thus potentially shorting surgery time. Attwo months,X-ray films showed that the granuls hadremained in position without any dislocation .The β-TCPused in the present study fused with the surrounding bonein about two months.This result is in agreement with otherreports that the bone conduction of β-TCP is high and thatβ-TCP will eventually absorbed and replaced by autologousosseous tissue.The pure phaseβ-tricalcium-phosphate(Cerasorb) isbelieved to a new bone grafting material in dealing withsegmental bone defect.