Performance of progressive and constant tapered instruments rotary systems at canal preparation

ABSTRACT Objective: The aim of this study was to compare the performance of two nickel-titanium rotary systems regarding the preparation time, final shape of canal, incidence of aberration, transportation, and fracture of instrument. Methods: A total of 40 simulated canals in resin blocks with 30o curves and a length of 17 mm were divided randomly into two groups: preparation with ProTaper and BioRaCe systems up to F5 and BR5 respectively. Pre- and post-operative canal images were taken and superimposed in order to identify aberrations, transportation, and to take measurements of the canal width. In addition, the preparation time and instrument fractures were recorded. The data were analyzed using Student's t test. Results: There is no difference (p>.05) comparing the systems regarding preparation time, canal aberration, and instrument fracture rates. The progressive tapered instruments of ProTaper prepared significantly larger canal widths in the apical third (p<.05). Conclusion: Overall, both systems provided safe canal preparation, associated with few canal aberrations and instrument fractures.

# 摘要
## 研究目的
本研究旨在比较两种镍钛旋转器械系统（nickel-titanium rotary systems）在根管预备时间、根管最终形态、畸形发生率、根管偏移及器械折断方面的性能差异。
## 研究方法
共计纳入40个带有30°弯曲、长度为17mm的树脂模拟根管块，随机分为两组，分别采用ProTaper系统与BioRaCe系统将根管预备至F5及BR5规格。拍摄术前及术后根管影像并进行叠加，以识别根管畸形、偏移情况并测量根管宽度。此外记录根管预备时间与器械折断事件，数据采用学生t检验进行分析。
## 研究结果
两组在根管预备时间、根管畸形发生率及器械折断率方面均无显著差异（p>0.05）。ProTaper系统的逐步锥形器械在根尖三分之一区段预备的根管宽度显著更大（p<0.05）。
## 研究结论
总体而言，两种系统均可安全完成根管预备，且伴随较低的根管畸形发生率与器械折断风险。