机用ProTaper两步法预备根管的器械折断情况的体外研究

【摘要】 目的 评价分析机用镍钛器械在两步预备根管时的器械折断情况。方法 采集600颗离体磨牙,分成对照组与实验组，各300颗,对照组用常规机用ProTaper一步预备到位(S1-Sx-S2-F1-F2),实验组分两步预备根管(第一次:S1-G Grill-S2;第二次:F1-F2),最后统计分析每组器械折断情况,使用SPSS18.0软件包对结果进行卡方检验。结果 2种方法预备根管过程中发生器械折断率和器械折断长度显著性差异（p<0.05），但在不同根管长度里预备器械折断率实验组虽然比对照组少但差别无统计意义，下颌磨牙器械折断36个(76.6%) 较上颌磨牙多, 且上下颌磨牙多发生在近中根管；器械折断的位置多位于根管弯曲的中段28个(59.6%);器械折断多发生于弯曲度大于30°的复杂根管41个(87.2%),两组之间无统计学差异。结论 根管治疗中机用Protaper使用两步法预备可以降低器械折断率。

The instrument fracture of rotary ProTaper files in root canal preparation:in vitro study

Abstract: Objective To evaluate the nickel titanium instruments fracture using two steps in root canal preparation. Method: Six hundred anterior teeth were selected. The teeth were divided into two groups, and there were 300 teeth in each group. One step group (control group), which prepared the root canal only once by ProTaper nickel—titanium files (S1-Sx-S2-F1-F2), and another group (experimental group) which prepared the root canal twice (First time:S1-G Grill-S2;Second time:F1-F2). The data were analyzed by SPSS18.0 software package for chi square test. Results: The incidence of instruments fracture and the length of instrument fracture part showed significant differences (p<0.05) between two groups. There were no significant differences in the length of root canal (P > 0.05) between two groups though the incidence of the experimental group instrument fracture was lower than that of control group. The majority of the instruments fracture frequently occurred in mandibular molars, in which there were 36(76.6%)fractures, especially in mesial root canals; and there were 28(59.6%)fractures in the midpoint of the curvature and 41 (87.2%) in quite complex canals with curvature more than 30。.Conclusion: Two steps preparation used in root canal therapy could decrease the incidence of instruments fracture. It is a recommended method to do two steps preparation combining with clinical practice.