镍钛合金根管器械折断的临床分析

目的　分析镍钛合金根管器械在临床使用时的折断情况及原因 ,为其预防提供资料。方法　 2 0 0 1年 5月～ 2 0 0 3年 5月间收集在临床根管预备中折断的根管器械Profile和NiTiflex共 6 8根 ,记录折断器械的号数和锥度 ,扫描电镜观察其折断类型 ;并对折断器械在患牙中的分布、根管中的位置、与根管弯曲度之间的关系 ,以及折断的数量与时间之间的关系进行分析。结果　镍钛合金根管器械折断的类型多属弯曲折断 (71% ) ,且易发生于磨牙、根管弯曲中段、根管弯曲度大于 30°及较复杂根管的患牙。第 1年器械折断 4 5根 (6 6 % ) ,第 2年为 2 3根 (34% )。结论　镍钛合金根管器械折断与患牙的根管状况、术者的操作经验及使用方法等因素紧密相关。

Clinical analysis of the fracture of nickel-titanium instruments during root canal therapy

OBJECTIVE: To analyze the clinical fracture of nickel-titanium instruments and its causes. METHODS: 68 Profile and NiTiflex files broken during the clinical root canal instrumentations in two years were collected. The analysis was carried out regarding the relation between the broken files and the distribution in the teeth, canal, degree of curvature of canals, and the relation between amount of the broken files and the period. RESULTS: The majority of the clinical fracture of nickel-titanium instruments were flexural fatigue which frequently occurred in molar, the midpoint of the curvature, canal with curves > 30 degrees and very complex canals. Amount of the broken nickel-titanium instruments in the first year was twice than that in second year. CONCLUSION: The fracture of nickel-titanium instruments is closely related to the anatomy of the root canal, the operator's experience and the usage of instrument and so on.