[Experimental study on the healing processes after the immediate reconstruction of maxillary bone defect--fresh autogenous iliac bone graft].

Abstract

This study was designed to investigate the healing processes of fresh autogenous bone grafted from iliac to maxillary bone defect, which was an artificial oro-antro fistula and covered with submucosal flap made by ckeek mucosa. The experiments were carried out in vivo on adult mongrel dogs ranging 7,14,30,90,180 and 360 days postoperatively. Radiographic and histological investigations were made to evaluate details, further study has made by means of X-ray contact microradiography (CMR), tetracycline (TC) labeling and angiographic images. Results 1. Radiographic findings, the grafted bone remained unchanged until 14 days postoperatively. The bone bridge formation between host and grafted bone was completed after 30 days in all of the cases. Bone resorption can be observed at 90 days postoperatively, which were as much as one second or one third of grafted. But thereafter there were no changes on the grafting bone area, that is to say, bone resorption ceased and stabilised. 2. Histological findings, inflammatory changes can be mainly observed at the early postoperative stages. And osteoclasts and new bone formation can be observed along the host bone. On 14th postoperative day, all of the grafted bone cells turned to necrosis. Osteoclasts and the new bone formation were observed in that area. 30th postoperative day, new bone formation made connector between host and grafted bone area. And medullary cavity of the grafted bone was filled with fibrous connective tissue, new bone formation and bone resorption occurred at the same spot. On 90th day old grafted bone was scattered like an island among new bones. In 180 days, grafted area was nearly normal maxilla. 3. 7th postoperative day, inflammatory changes can be mainly observed on the mucosal bed of the grafted bone, those diminished in 14 days. It was completely changed to dense fibrous connective tissue. 4. Angiographic images, vascularization to medullary cavity of the grafted bone started on 7 days. In 14 days, vascularization filled about half of the grafted bone. Vascularization was also observed a little in cortical bone. It was completed throughout the entire grafted bone in 30 days and it connected with the host bone. In 180 days, the grafting bone was nearly normal angiographic image. 5. Contact microradiogram, the new bone formation was partially observed in the host bone in 7 days. In 14 days, the bone bridges formation started. It was almost completed in 30 days after transplantation. In 180 days, it was entirely completed. 6. Tetracycline labeling, the host bone was labelled weakly in the early postoperative stages.(ABSTRACT TRUNCATED AT 400 WORDS)