Autologous cortical bone block for repair of implant-site jaw bone defects / 中国组织工程研究

BACKGROUND: Autologous bone with good biocompatibility possesses the characteristics of bone conduction, osteoinduction and osteogenesis. However, the healing process after autologous bone grafting is still controversial. The focus of controversy is whether the bone graft is completely absorbed and replaced or whether it can retain cell viability for a long time. OBJECTIVE: To observe the histological changes in bone remodeling and regeneration after cortical bone grafting. METHODS: Six healthy beagle dogs were selected as the research animals. The maxillary premolars of experimental dogs were extracted and the bone plates with width of 10 mm, length of 15 mm and thickness of 2 mm were removed from the buccal side. A bone defect model was established. The corresponding size of cortical bone block was cut on the buccal side of the bilateral mandibular body. Cortical bone grafts were fixed in the maxillary defect area. On one side pure cortical bone block was used as grafting material; on the other side the implant was placed simultaneously with the bone graft. Samples were harvested at 3 and 6 months after bone grafting. The cell survival and bone graft resorption of autologous cortical bone graft were analyzed by gross observation and histological observation. The study protocol was approved by the Animal Ethics Committee of Dalian Medical University, China. RESULTS AND CONCLUSION: The size of the grafted bone was gradually reduced, and the margin was blunt and firmly bonded to the base bone. All implants lost after 6 months. A newly formed connection between the graft and the base bone was shown by hard tissue ground sections. The porosity of bone lacuna in the grafted bone block at 6 months was significantly lower than that at 3 months (P < 0.05). The grafted bone resorption rate at 6 months was significantly higher than that at 3 months (P < 0.05). These findings indicate that osseointegration exists between grafted cortical bone block and the base bone of the recipient area. Osteocytes in the graft bone partially remain alive. With the prolongation of healing period, the proportion of new bone cells increases, and the volume of the grafted bone gradually decreases. Osseointegration of the concurrent implant is disturbed due to the absorption of cortical bone graft.

A Retrospective Study of the Surgical Success and Vertical Bone Resorption Rate after Autogenous Block Onlay Graft in Posterior Maxilla

PURPOSE: The purpose of this study was to evaluate the surgical success of bone reconstruction of the severely atrophic maxilla using autogenous block bone onlay graft from the ramus and ilium prior to dental implantation. And we measured the amount of vertical height change MATERIAL AND METHODS: 26 partially edentulous patients(32 case) who needed block onlay bone graft before implant placement in posterior maxillary area from 2002 to 2009 were selected for this study. Patients consisted of 20 males &6 females and the average of their age was 54.2. Patients who were treated with ramal bone were 19 case and patients who were treated with iliac bone were 11 case. Digital panoramic X-ray was taken at the day of surgery, 3 months and 6 months later after the surgery. Vertical height change&resorption rate of grafted bone were measured with the same X-rays and compared RESULTS: Two out of 32 bone grafts had to be removed because of inflamation at the grafts area(97.3%). The mean of radiographic vertical height change(change rate) of post-op. 3 month was 0.54mm(8.5%)and 6 month was 0.99mm(15.9%). Compairing to intraoral donor site(ramus), iliac bone had more vertical height change(1.18mm) at 6 month after surgery. CONCLUSIONS: Within the limit of this study, autogenous block onlay grafts can be considered a promising treatment for severely atrophic maxilla.

Treatment of Tibial Nonunion with Subcortical Onlay Bone Graft and Plate Fixation / 대한정형외과학회잡지

Tibial nonunion is often associated with the soft tissue atrophy and the local circulatory disturbance, so it is important to minimize the soft tissue injury and maintain the stability at fracture site for bone union. We reviewed 29 cases of subcortical onlay bone grafts and plate fixations for the nonunion and delayed union of tibial shafts, from Jan. 1988 through Jan. 1994. The results were as follows. 1. Twenty-nine patients who had nonunion of the tibia underwent subcortical cancellous onlay bone graft and plating, and 28 fractures(96.6%) went on to union. 2. Subcortical elevation or shingling of cortical bone fragments of the tibial cortex, is advocated to provide sound biological condition in atrophic soft tissue envelope. 3. Narrow DCP encouraged early motion and reliably promoted obtaining anatomical alignment. So, in treatment of protracted tibial nonunion, especially in an area with deficient soft tissue or unyielding scar tissue, subcortical onlay bone graft and plate fixation is very useful method, result in good union and no skin problem.