A collagen membrane for periosteal expansion osteogenesis using a timed-release system in rabbit calvaria.

BACKGROUND: The purpose of this study was to evaluate the effects of resorbable membranes, combined with a shape memory alloy (SMA) mesh device, on bone formation using a timed-release system for periosteal expansion osteogenesis (TIME-PEO). MATERIALS AND METHODS: Twelve Japanese white rabbits were used in this study. An SMA device was inserted under the forehead periosteum, pushed and bent for attachment to the bone surface, and then fixed using resorbable thread. The rabbits were divided into four groups: C1 (5 weeks postoperatively without membrane), C2 (8 weeks postoperatively without membrane), E1 (5 weeks postoperatively with membrane), and E2 (8 weeks postoperatively with membrane). The rabbits were killed 5 or 8 weeks after the operation and the newly formed bone was assessed histologically and radiographically. RESULTS: SMA devices, concealed under soft tissue until the time of euthanasia, did not cause active inflammation. The mean activation height, from the original bone surface to the midpoint of the mesh, was 3.1 ± 0.6 mm. Newly formed bone was observed, and most of the subperiosteal space underneath the device was occupied by fibrous tissue. Immature bone was present at the outer surface of the original skull bone in all groups. On histomorphometric analysis, there was no significant difference in the volume of the new bone between C1 and E1 (p = 0.885), and C2 and E2 (p = 0.545). CONCLUSIONS: PEO using an SMA mesh device, which is based on guided bone regeneration (in atrophic alveolar bone), shows promise as an alternative for bone augmentation, irrespective of whether a resorbable membrane is used.

Histologic and histomorphometric evaluation of the bone regeneration following cortical bone repositioning in a rabbit mandible.

BACKGROUND: Although bone graft (BG) is the gold standard for bone augmentation, its use is hampered by donor site morbidity and limited quantity. PURPOSE: To evaluate the capabilities of bone formation by cortical bone repositioning (CBR) as the healing response following grafting of autogenous bone block without filling biomaterial at the gap between gap and recipient. MATERIALS AND METHODS: Twelve Japanese White rabbits were divided into three groups (postoperative 2, 5, and 8 weeks). A cortical block was freed from the mandibular body, half of the block was positioned and fixed overlapped the original bone surface beside the defect and the other half remained only elevated above the defect. Three areas were decided for the evaluation; BG, CBR, and defect (D) area. Areas were evaluated by micro-CT, histology, and histomorphometric analysis. RESULTS: There is no statistical difference between BG and CBR by evaluating distance and area in histomorphometrical analysis (P < .05). D area showed statistical decrease compared with BG and CBR at week 2. Histologically, new bone was evident at week 2, mature bone was observed in all three areas at week 8, D area disappeared and fused completely with the elevated bone block. CONCLUSION: CBR has potential for bone augmentation as BG induced from its own regenerative ability of healing process.