儿童恒前牙切髓术后根髓组织学研究

The study of histomorphological characteristics of radicular pulp of permanent incisors in children after partial pulpotomy

目的 :牙本质桥的形成是牙髓修复的特征 ,但至今人们对牙本质桥下方的牙髓组织是否健康仍有争议。本研究目的是观察儿童外伤冠折恒切牙切髓术后根髓的组织学特征 ,以证实牙髓修复后的牙髓组织变化状况。方法 :对 16例 8～ 9岁儿童外伤冠折露髓的恒前牙行切髓术 ,氢氧化钙制剂覆盖牙髓断面 ,并在牙本质桥形成及根尖发育完成后不同时期行去髓术 ,将去除的根髓组织固定 ,常规组织学切片、显微镜观察。结果 :术后 12～2 4个月根尖发育完成 ,此时组织学观察可见牙本质桥下方的根髓组织无明显炎症。至 36～ 48个月 ,牙髓组织逐渐出现退行性变 ,例如纤维性变和牙髓钙化等。结论 :切髓术后 2年内牙本质桥下方的根髓是正常的 ,而后牙髓逐渐出现退行性变 ,切髓术可作为儿童前牙冠折露髓的一种暂时治疗方法 ,当牙根发育完成时 。

AIM: Formation of dentin bridge seems to be a consistent feature of repairing dental pulps. However, the pulp tissues covered by dentin bridge are healthy or not, still in controversy. The purpose of the present study was to observe the histomorphological characteristics of radicular pulp of traumatic crown fractures in permanent incisors after partial pulpotomy, and to testify the histopathological changes in pulp tissues covered by the dentin bridge formed along the dentin walls during pulp repair.METHODS:Pulpotomy was done on 16 exposed pulps in crown-fractured permanent incisors of 8～9 years old children with immature roots. The pulp wounds were covered with calcium hydroxide product.After the dentin bridge formed and the root development was complete, pulpectomy was performed in various periods.The pulps were fixed in 10% neutral buffered formalin, embeded in paraffin, sectioned routinely and observed under microscope. RESULTS: At 12～24 months after treatment, the root development was completed and no obvious inflammation in pulp tissues below the dentin bridge. Then, at 36～48 months after treatment, degenerative changes, such as fibrous degeneration and calcification, gradually occurred in the remaining pulps. CONCLUSION: Within 2 years after pulpotomy, the radicular pulp below the dentin bridge is healthy. However, degenerative changes of the pulp will take place thereafter. The pulpotomy may be regarded as a temporary treatment and should be followed by pulpectomy when the root development is complete.