Experimental And Clinical Study For Bone Regeneration In The Bone Defect Around Implant

The surrival of implant is dependant on osseointegration; Which needs adequate bone tissue in alveolar ridge. Due to lack of stimulus of mastication in edentulous regions, the highness and width of the ridge will be reduced, and primary stability and long-time successful rate will be affected. How to deal with this problem is still a research topic in the field of oral implantology. Nowadays, there are three bone grafts for repair of bone defects around implant autogenous graft, allograft and alloplaster. All of them has its own limitation for clinical uses. For promotion of osseointegration, some scholars recommended bone growth factors and guided bone regeneration in combination with bone transplantation.In the experimental investigation, three methods were used for repair of bone defects around implant in thigh (dog). By means of radiograpru SEM and histology, the osteoinduction of DFDBA and effects of rhBMP-2 and titanium membrane on DFDBA were studied.In the clinical study, 8 cases with peri-implant bone defects were treated by freeze-dried surface-demineralized allogeneic banked bone. 8 implants were put in those patients. Implant stability, periodontal change and osseointegration were evaluated by ccinical observation and radiography, postoperatively.The whole investigation was be divided into 4 parts:The first part(radiography): CDIC implants were put in the thighs, then 4rnmx3mmx3mm bone defects were made around implants. In order to repair the bone defects, DFDBA.DFDBA +rhB- MP2, DFDBA+ titanium membrane were used. At 4, 8, 12 weeks of postoperation, the specimens were assessed by computer-assisted densitometric image analysis. The bone regener ation and density were analysed for osseointegration. The results were as follows: in DFDBA group, bone defects were occupied by new bone slowly. At 12 weeks postoperatively, new bone was connected with host bone, basically. But there are definitely difference between new bone and host bone density (P<0.01). It indicated that DFDBA could be applied for repair of peri-implan bone defect, but its bone regenerative process was long; In DFDBA+ rhBMP-2 group, new bone was framed earlier than that of DFDBA group. At 12 weeks postoperatively, there were no difference between new bone and native bone, in term of bone density(P<0.05). This demonstrated that rhBMP-2 could increase osteoinduction of DFDBA; In DFDBA+ titanium membrance group, the bone formative process was similar to that of DFDFB+ rhBMP-2. But at 8 weeks postoperatively, the amount of new bone and bone density were increased greatly. It indicates that titanium membrane has the capacity of guided bone regeneration. It can also keep fibrous tissue from new bone.The second part(SEM): CDIC implants were inserted in the thighs, then 4mmx3mmx3mm bone defects were made around implants. In order to repair the bone defects, DFDBA, DFDBA +rhBMP2, DFDBA+ titanium membrane were used At 4, 8, 12 weeks of postoperation, the specimens were assessed by SEM. The gap between new bone and implant was recorded, in order to analysed the primary stability of implant and osseointegration. Results: showed that in DFDBA group,fibrous tissue and calcium materials were found in the gap between host bone and implant at 4 weeks postoperatively. InDFDBA+ rhBMP group, new bone was found in the region of bone graft, and some of new bone were near the implant surface. In DFDBA+ titanium membrane group, new bone grew along implant, but the gap was definitely clear. In DFDBA group: the amounts of new bone and calcium crystals were increased at 8 weeks postoperatively, but the gap is still clear. In DFDBA+rhBMP-2 group; woven new bone formed along implant, the gap was shortened. In DFDBA+ titanium membrane group, fibrous-like new bone and calcium deposit were increased, the gap became small. At 12 weeks postoperatively, DFDBA group, new bone near to implant surface. The gap unclear. In DFDBA+rhBMP-2 group: new bone- covered the gap and connected with host bone tightly. In DFDFA + titanium membrane group calcium deposit increased a...