An Experimental Study of the Periapical Healing after Apexification on the Immature Pulpless Teeth

摘要对有延髓根管的未成熟非活髓恒牙根尖诱导成形术后根尖周伤口愈合情况进行组织学观察。本文对3例4岁左右的食蟹青年恒牙的健康情况进行了研究，在全身麻醉和局部麻醉下，用橡皮障隔离法开髓，然后拔除冠髓。用高频电烧灼、凝固残根髓，分为感染组和非感染组，1周后进行感染根管治疗，根管消毒后用氢氧化钙或FR-Ca糊剂根管内涂抹。在实验期结束时，1，3，5个月，通过用中性福尔马林灌注处死动物。制备脱钙石蜡连续切片，苏木精-伊红染色，光镜观察。与电极接触的牙髓组织凝固，但离其一定距离处仍有活髓存在.根管壁较薄的未成熟牙，根锥温度升高引起牙周膜和牙槽骨灼伤，外根吸收和/或与骨发生强直.非感染组在氢氧化钙根尖诱导成形术后，根尖区可见大量骨牙本质增生，充填根管间隙.骨牙本质可使牙根继续发育，但根尖形成异常，根管严重钙化，今后将与感染组进行比较，并作进一步研究。

Periapical wound healing after apexification on immatured non-vital permanent teeth with bulunderbass canals were evaluated histologically. This investigation was undertaken on sound permanent teeth in three crab-eating young mondeys aged four approximately.Under general and local anesthesia, access openings of the teeth were performed with rubber-dam isolation, then the coronal pulps were extirpated. Remnant root pulps were cauterized and coagulated with high frequency current, and then divided to two groups, one was infected group, and other was non-infected groop.One week later, infected root canal treatment was started, and calcium hydroxide or FR-Ca paste was applicated to the canal after root canal disinfection. At the conclusion of the experimental period, 1,3,5 months, the animals were sacrificed by perfusion with neutral formalin. Decalcified serial paraffin sections were prepared and stained with hematoxylin-eosin, and observed by light microscopy.The results obtained were as follows :1. The pulp tissue which contacted with eletrode was coagulated, but at some distance from it vital pulptissues were still existent in alive.2. The burn caused by a rise in temperature of the root conal was observed in the periodontal ligaments and alveolar bone on the immature tooth with thiner root canal wall, and external root resorption and/or ankylosis with the bone were observed.3. After the apexification with calcium hydroxide on non-infected group, addition of severe osteo-dentin which filled up the canal space was observed at apex area.4. Continual development of the root by osteo-dentin was observed, but abnormal formation of root apex and severe calcified of root canals were appeared.In future, these results will be compared with infected groop, and details will be investigated further.