| Objective:As one of the important ways to treat missing teeth,implant denture restoration has a wide range of clinical applications.Sufficient and healthy bone mass is the prerequisite for obtaining and maintaining long-term implant osseointegration.In order for patients with insufficient bone mass to obtain satisfactory implant restoration effects,clinical treatment often uses bone grafting to create better bone conditions for the implant area.As a result,bone graft materials have become the focus of research.Demineralized bone matrix(DBM)as a bone-derived material has good biological properties,and the polymer material poly L-lactide-co-caprolactone(PLCL)has good mechanical properties.The combination of two materials can achieve complementary performance.In this experiment,an animal model of bone defect was established to evaluate the ability of DBM,DBM/PLCL and the commonly used Bio-Oss bone graft materials to repair bone defects,and to explore the effect of their use in bone defect repair.Method:1.Material preparation:(1)Preparation of DBM : Take fresh porcine tibia,decellularize and decalcify,grind it into powder,and freeze-dry it for use(2)DBM/PLCL Preparation of composite materials: Place the DBM in a 1% PLCL solution for 3 days after cross-linking,and then dry it for later use.2.Critical Size Defect(CSD): select 60 male SPF Wistar rats,weighing 400±20g,and make a defect of 3.5×4.0mm in size and 2mm in the middle and upper end of the left tibia.Bone defect,establish an animal model of bone defect.The left tibia of all rats is the surgical side,and the right tibia is the normal group.The surgical side was divided into 4 groups,the vacancy group,Bio-Oss group,DBM group and DBM/PLCL group.3.Inspection method: 5 rats in each group died in the 4th,8th,and 12 th week after the operation,and the left and right tibia were taken.(1)Generally observe the residual material,surface and medial healing of the defect;(2)Detect the bone density of the defect by X-ray plain film;(3)Use cone-beam CT scanning to obtain three-dimensional reconstruction images and cross-sectional images of the specimen,analyze the central bone density and bone shape height of the operation area;(4)H-E and Masson staining were performed on the decalcified samples to observe the shape recovery,bone cortex regeneration,new bone maturity and material degradation,and use software SPSS20.0to statistically analyze the Masson stained new bone area percentage.Result:1.Material preparation: DBM and DBM/PLCL are both sponge-like with loose structure;DBM is soft in texture and light yellow in color;DBM/PLCL is slightly whiter in color and slightly tougher than DBM.2.Construction of the ultimate bone defect model: A tibial bone defect of3.5×4.0mm×2 mm was successfully constructed in the rat tibia.At various time points after surgery,the gross observation,imaging and histological results of the blank control group showed that the bone defect was not completely repaired,which met the CSD standard.3.Postoperative observation(1)General results: The surgical area of the vacancy group was obviously sunken,the surgical area of the Bio-Oss group was gradually flattened,and the hardness of the acupuncture in the DBM group and the DBM/PLCL group gradually increased;the medial cortical bone of the DBM/PLCL group The height is gradually flush with the host bone.(2)X-ray and CBCT imaging results: As time goes by,the number of new bones in the defect in each group gradually increased,among which the Bio-Oss group performed best,the DBM and DBM/PLCL group performed slightly,and the vacant group was the worst.But at various postoperative time points,the repair of the medial cortical bone in the operation area in the DBM/PLCL group was significantly better than that of the DBM Group(P<0.05),PLCL showed a certain osteogenesis advantage.(3)The histological staining results showed that the new bone in the defect of the operation area grew into the center along the edge of the material,and the new bone tissue gradually increased over time.At 4and 8 weeks after operation,the area of new bone in the Bio-oss group was significantly better than that of the DBM group and DBM/PLCL group(P<0.05),and there was no statistical significance in the DBM group and DBM/PLCL group(P>0.05);After 12 weeks,there was no significant difference in the area of new bone between the DBM group and the Bio-oss group(P>0.05),and it was larger than the DBM/PLCL group(P<0.05).In addition,no stent material was observed in the DBM group at 4 weeks after surgery,while 31.63% of the material remained in the DBM/PLCL group at 12 W after surgery.Conclusions:1.DBM can promote bone regeneration,but it degrades rapidly and the role of the scaffold is poor,and the bone shape recovery is not ideal;2.DBM/PLCL degrades slowly,has a certain amount of space maintenance and better osteogenesis,the bone defect shape repair effect is better than DBM;the addition of PLCL will delay the generation and maturity of new bone3.Filling with Bio-oss bone meal can better osteize and restore the bone shape of the operation area,but Bio-Oss bone meal has no obvious degradation. |
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