Preparation Of Odontogenic And Porous Biphasic Bioceramics And Experimental Study On Repairing The Bone Defects

Objective:The aim of this study is to prepare the odontogenic and porous biphasicbioceramics with the detachment teeth,testing its microstructure andphysical-chemical properties,then use animal experiments to evaluate theosteogenesis ability of the material.Methods:The detachment teeth were calcinated preliminarily in order to remove theorganic principle,and calcinated permantly after immersing the aqua of (NH4)2HPO424h.The product was biphasic bioceramics,which were composed ofHydroxyapatite(HA) and β-tricalcium phosphate(β-TCP),then were comminutedthrough200mesh screen.A forming technology of porous ceramics with dippingpolymeric sponge in slurry was applied.At the same time,a series of examinationwere carried out including energy dispersion analysis of X-ray（XRD）,scanningelectron microscope(SEM),the porosity of scaffolds,elemental analysis andcompressive strength.48adult New Zealand rabbits were randomly divided into4groups.The bone defectmodel(length18mm,width5mm,thickness3mm) in both sides of the tibia wascreated.Defect was untreated in group A,while defect was repaired with biphasicceramic biologic bone in group B,with porous biphasic bioceramics in group C,withBio-oss in group D.At4,8, and12weeks after operation, gross observation,X-rayradiography and histopathological observation were performed. The generation rateof new bones was calculated by morphology image analysis system ofHPIAS-1000.The software package SPSS17.0was applied for one-way ANOVA(α=0.05). Results:(1)The odontogenic and porous ceramics was white.The results of XRDshowed that the main phases were HA and β-TCP. SEM observation revealed that theceramics presented reticular structure with macropore and micropore.The porosity ofscaffolds was74.85percent. The Ca and P element contents in the samples wasrespectively(%)38.11and18.27.The calcium to phosphorus ratio of bioceramicswas1.62and the compressive strength could attain（3.483±0.321）MPa.(2)Animal experiments:there was no operation infection and fracture case,and thepostoperative reaction was lightly. With the prolonging of time,the bone defect ofgroup A was still dominated by fibrous tissue.A lot of new bone formed in the otherthree groups,but the repairing effect was better in group D than in group C.Thedifference among group A,B,C and D had statistical significance(P<0.05).Conclusion:The odontogenic and porous biphasic ceramics has goodbiocompatibility and osteogenic property, which make a rich source of detachmentteeth play more valuable application.But there are many areas for improvement inthe study,which can increase the porosity of the material and lay a more solidfoundation for the clinical application in the oral fields.