前颌中缝牵张修复牙槽裂的实验研究

目的　探索用缝牵张成骨技术以组织再生的原理修复牙槽裂。方法　采用犬牙槽裂模型 ,牙槽裂形成术后 2周 ,于前颌中缝处安置缝牵张器 ,外张力 2 0 0g。牵张 2～ 3周 ,裂隙侧的前颌骨向侧方移动贴紧远中裂缘 ,用局部黏骨膜瓣修复牙槽裂隙。保持 2周后去除缝牵张器。临床观察、连续X线、头颅干骨和组织学检查评价治疗结果。结果　所有对照动物形成规则的牙槽裂 ,无自发骨性愈合。前颌中缝牵张后 ,裂隙侧前颌缓慢向裂侧上颌靠拢 ,2～ 3周与远中裂缘密切贴合。X线片示前颌中缝呈现由窄渐宽的三角形 ,三角形的尖端指向后方 ,三角区域的骨密度逐渐增加。骨膜成形术后 3个月 ,原牙槽嵴缺损处骨质连续性完全恢复 ,且牙槽骨段在三维方向上均与对侧相同。前颌中缝恢复正常直线形态。结论　该牙槽裂模型稳定性和重复性好 ;前颌中缝牵张诱导缝区新骨形成 ,一侧前颌向裂隙移位和局部骨膜成形可达到完善的牙槽裂修复。

Mid-premaxillary sutural distraction osteogenesis for repair of alveolus cleft:an experimental study in dogs

Objective To explore a new technique for repair of alveolar cleft by sutural distraction osteogenesis. Methods Nine 8-weeks mongrel dogs were used in this study,three being in the control group,six in the experimental group.Alveolar cleft model was created surgically in all animals. Two weeks later,a U-shaped distractor made of Ni-Ti memory alloy wire was insterted into the premaxilla to distract the mid-premaxillary suture.When the premaxilla of the cleft side approached the ipsilateral maxilla,periosteoplasty of the alveolar cleft was performed.The distractor was removed at two weeks after periosteoplasty.The results were evaluated clinically,radiographically,morphologically and histologically. Results The cleft model in dogs was stable and similar to the human alveolar cleft. In experimental dogs,the premaxilla was moved gradually toward the maxilla so that the cleft was closed. The distracted mid-premaxillary suture showed a gradually widened traingle,with its tip being posterior.The density of the distracted traingle suture was increased gradually.Bony repair was achieved completely at the cleft three months post-periosteoplasy.The morphology of the mid-premaxillary suture was restored. Conclusion The alveolar cleft could be repaired by the technique of mid-premaxilla suture distraction.