The Study Of Repair Of Mandibular Defect Using PDLLA/TCP Composite

Objective To investigate the effect of PDLLA or PDLLA/TCP composite on mandibular defect repair and estimate the feasibility of mandibular defect repair by them.Materials and methods The model of mandibular defect was created in sixty Wistar rats. Twenty defects were filled with PDLLA/TCP composite; twenty were filled with pure PDLLA; the others were filled with nothing-as the control group. The clinical observation, X ray photography, histological observation and immunohistochemistry of TGF- ? OPN, OC, BSP were taken at the 2nd, 4th, 8th, 12th, I6th week after mandibular defect filled with PDLLA or its composite.Results All rats recovered well. Local inflammation was found in two of rats in group PDLLA 2 weeks after operation and then developed into fistulas. Mandibular fracture was found in one rat in control group. The histological study showed that osteoblasts and fibroblasts were more active in test group in the early healing stage. The filled materials were divided into several parts by new fibro tissues. There are large numbers of new bone islands in the defect areas of test group. High expression level of TGF- ?, OPN, OC, BSP were observed in the tissues around defect in immunohistochemical study two weeks after operation in both test group and control group. However the strong expressions last 8 weeks and still can be found after 16 weeks after operation in the test group. But the expressions descend very fast in the control group.Conclusion Both pure PDLLA and PDLLA/TCP composite can repair rats mandibular bone defect. PDLLA/TCP composite promote bone formation prior to the pure PDLLA. The high expression level of TGF-?, OPN, OC, BSP around defect showed lasting high activity of bone formation. PDLLA/TCP composite is a better biodegradable material for mandibular bone defect.