| Objective: In the clinical diagnosis and treatment of common patients due to periodontal disease,dental caries and trauma caused by tooth loss,Implant repair is a reliable way to repair missing teeth.Adequate alveolar bone mass is a key factor in the long-term survival and success of implant dentures.Due to lack of stimulation to the alveolar bone caused by long-term lack of teeth,some patients have different degrees of vertical and horizontal bone absorption,and bone grafting is needed during the operation.Currently used bone graft material include autologous bone,heterogeneous bone,allograft and artificial bone,etc.,however which bone graft material has more advantages,at present there is no agreement.Experimental studies have shown that: collagen / tricalcium composite bone graft has good biocompatibility,biodegradability and bone conduction role,is expected to be an ideal bone graft material.In addition,the use of dentine particles as a bone graft material for the repair of jaw defects has also yielded satisfactory results in basic research and clinical applications.In this experiment,the model of bone defect was made on the SPF rat skull.The collagen / tricalcium phosphate and the treated dentin pellets were respectively implanted onto the skull bone.Osteogenic differences between the collagen/tricalcium phosphate materials and dentin granules were observed.Materials and methods:1.Collagen / tricalcium phosphate composite materials: The experiment used by the collagen production of bone packing.It is a mixture of ?-TCP and collagen that is absorbable by the body.The two materials are cross-linked by temperature-dependent dehydration,UV irradiation and freeze-drying.2.Preparation of dentin particles: The clinical collection of teeth were cleaned,removethe surface of periodontal fibers and pulp and other soft tissue,with high-speed turbine drill remove enamel,cementum,retaining only dentin.The prepared dentin was milled,pulverized to a particle with size of about 0.2 mm in diameter,and boiled and isopropanol degreased sterilized.3.Group of experimental animals: Forty healthy SD rats were selected and randomly divided into A1,A2 and B1,B2 four groups of 10 mice each.Group A1 A2 was implanted with collagen / tricalcium phosphate composite graft,and groups B1 and B2 were treated with dentin granules.Groups A1 and B1 were sacrificed at 4 weeks after transplantation.Groups A2 and B2 were sacrificed 12 weeks after transplantation.Results:1.General observation: The experimental animals were sacrificed at 4 weeks and 12 weeks after operation,and the surface skin of the implant area was dissected after incision.No infection or exposure of the wound was found in the 4 groups of experimental animals.At 4 weeks,the A1 group had obvious absorption of the implanted material,soft tissue collapssion,soft touch and obvious mobility.B1 group showed,no soft tissue collapse,a small amount of dentin absorped,surrounded by fibrous tissue,soft touch,have a certain degree of mobility.At 12 weeks,the majority of A2 group implanted material absorption,only a small amount of implant material remain,mainly filled with the fibrous connective tissue,no significant hardness change were found.B2 group dentin absorption changes little,fullness,hardness increased over 8 weeks,mobility decreased.2.Histological observation: At 4 weeks,some of the implanted materials in group A1 were absorbed,and the remaining ?-TCP particles were surrounded by a large amount of fibrous connective tissue,showing new blood vessels and multinucleated phagocytes.There was no new bone formation,no trabecular structure and no mature bone cells in the surface of the skull.In group B1,a large number of fibrous connective tissue wrapped dentin particles,showing some of the new blood vessels and multinucleated phagocytes,and no dentin particles obviously absorbed.A small amount of new bone can be seen at the contact between dentin granules and skull,and active osteoblasts can be seen between the trabecular bone.At 12 weeks,microscopic observation with HEstaining showed that only a small amount of implanted material remained in A2 and the remaining graft material was surrounded by a large amount of fibrous connective tissue.The number of new blood vessels increased and the number of multinucleated phagocytes did not change significantly.No new bone formed,no trabecular structure,no mature bone cells existed in the proximal and distal skull in group A2.B2 connective tissue around dentin particles decreased,new bone formed between dentin granules and skull,with trabecular bone and active osteocytes,but no significant difference compared with 4 weeks.3.Statistical analysis: No new bone was found in group A,and new bone was found around dentin particles in group B.Statistical analysis showed significant differences between groups A and B.Conclusions: The present study found that the selected collagen / tricalcium phosphate composite graft failed to induce new bone formation in onlay bone grafts,and the absorption of ?-TCP particles was faster than dentin granules.Therefore,this collagen / tricalcium composite bone graft material is unsuitable to use in onlay bone grafting.Dentin particles display good space-maintaining capacity and osteoconductivity,which is feasible to be used in onlay bone grafting. |
PDF Full Text Request