Clinical Research
Instrument Separation Analysis of Multi-used ProTaper Universal Rotary System during Root Canal Therapy

https://doi.org/10.1016/j.joen.2011.02.021Get rights and content

Abstract

Introduction

The purpose of this study was to identify the influential factors responsible for clinical instrument separation of reused ProTaper Universal rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland).

Methods

Six thousand one hundred fifty-four root canals in 2,654 teeth were prepared using ProTaper Universal files in endodontic clinics. Separation incidence was determined based on the number of treated teeth or canals. Data were collected including the size of fractured instrument, the length and location of a broken segment within the root canal, and the curvature of canal. The chi-square test and independent samples t test were used to determine the statistical significance.

Results

The overall instrument separation incidences were 2.6% according to the number of teeth and 1.1% according to the canal number, respectively. Separation incidences according to the number of teeth or canals were significantly higher (P < .05) in molars than those in premolars or anterior teeth. Because of its largest diameter, F3 file presented the highest separation incidence according to the number of teeth (1.0%) or canals (0.4%); 47.5% instrument separation of mandibular molars and 61.5% instrument separation of maxillary molars happened in the mesiobuccal canals. Moreover, 91.4% fragments were located in the apical third of root canals, and 54.2% instrument separation occurred in severely curved canals. There was a significant difference (P < .05) in the mean fracture length between shaping (2.42 ± 0.73 mm) and finishing files (3.32 ± 0.73 mm).

Conclusions

Separation incidence according to the canal number is more reliable than that according to the number of teeth because of the variable canal number in different teeth. The tooth type, rotary file size, canal location, and anatomy were correlated with the instrument separation of reused ProTaper Universal files.

Section snippets

ProTaper Universal File Instrumentation

Canal preparation was performed by the ProTaper Universal Series Rotary System according to the manufacturer’s recommendations using a crown-down technique. First, a gliding path was created using a #10 hand file to the working length. Second, an SX file was fed into the canal with a brushing outstroke motion for two thirds of its blade length. Third, a #15 hand file was passively used to reach the working length. Then, S1/S2 files were used with a brushing outstroke action until the working

Instrument Separation in Different ProTaper Universal Files

Overall, there were a total of 70 ProTaper Universal instrument separations (2 for SX, 16 for S1, 10 for S2, 11 for F1, 20 for F2, and 11 for F3, respectively) after 6,154 root canal treatments of 2,654 teeth. The overall prevalence of file separation was 2.6% according to the number of teeth and 1.1% according to the canal number, respectively. The F3 file showed the highest incidence of instrument separation (1.0% according to the number of teeth and 0.4% according to canal number), whereas

Discussion

The evaluation methods and results for the separation incidences of ProTaper rotary files are diverse in previous clinical studies. Wolcott et al (23) have shown that the overall rate of instrument separation was 2.4%. Another study has used 15 severely curved molars to assess the separation incidence of the ProTaper system with a 6.0% failure rate (24). Variations among these results may be attributed to the different clinical assessment approaches. For instance, all tooth types are involved

Acknowledgments

The authors deny any conflicts of interest related to this study.

References (40)

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