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目的探讨犬牙槽骨牵张成骨（alveolar distraction osteogenesis,ADO）牵张区新骨生长和改建的规律,为ADO技术在临床上应用提供实验依据。方法本研究于2012年10月至2014年1月在中山大学附属第一医院实验动物中心完成。选择健康成年杂种犬12只,拔除双侧下颌前磨牙,建立萎缩下颌牙槽骨动物模型。3个月后随机选择一侧萎缩下颌骨行牙槽骨切开术,植入2枚骨内型垂直向牙槽骨牵张器,经过7 d的间歇期,以每天1次,每次1 mm的频率进行垂直向增高,连续5 d。在固定期的第4、8和12周各处死4只犬并取材,采用扫描电镜/X-射线能谱联用仪观察牵张区新骨超微结构和测定其Ca、P元素含量。结果扫描电镜观察可见牵张区新骨不断钙化的过程,0~4周为新骨形成早期,〉4~8周为中期,〉8~12周为后期;X-射线能谱分析显示了牵张区骨成熟的过程,Ca、P含量逐渐增高,12周时和宿主骨含量相当。结论在牙槽骨牵张成骨的固定期,新骨逐渐形成并改建,至12周时成熟。

Ultrastructural and Ca,P changes of the regenerated bone after alveolar distraction osteogenesis in canine model

Objective To evaluate bone regeneration and remodeling of alveolar distraction osteogenesis （ADO）, provid- ing experiment evidence for the clinical application of ADO fechnique. Methods The experiment is performed in the Experimental Animal Center of the 1st Hospital of Sun Yat-sen University. Twelve healthy adult mongrel canines were provided, and they received posterior teeth extraction and alveoplasty in mandible to establish an atrophy alveolar model. After 3 months, a segmental alveolar osteotomy was made in the randomly selected unilateral atrophy alveolar and two alveolar distractors were placed. After a 7-day latency period, the alveolar ridge was augmented at a rate of 1.0 mm/d for 5 days. After a consolidation of 4, 8, and 12 weeks, the canines were sacrificed and the specimens of the distracted alveolar were harvested for scanning electron microscopic （SEM） study and element spectrum analysis of Ca, P contents. Resuits The distraction chamber revealed a distinctive dynamic ossification progress by SEM, early ossification stage in 1 to 4 weeks, intermediate stage of 4 to 8 weeks, and later remodeling stage of 8 to 12 weeks. Spectrum analysis indicated the maturation process of the al- veolar distraction zone with gradient increase of Ca, P content, which was comparable to host bone at 12 weeks after distraction. Conclusion New bone is formed and gradually remodeled during the consolidation period of ADO, and mature at 12 weeks.