Elsevier

Journal of Endodontics

Volume 45, Issue 9, September 2019, Pages 1135-1141
Journal of Endodontics

Basic Research
3-dimensional Ability Assessment in Removing Root Filling Material from Pair-matched Oval-shaped Canals Using Thermal-treated Instruments

https://doi.org/10.1016/j.joen.2019.06.003Get rights and content

Abstract

Introduction

The purpose of this study was to evaluate the ability of the XP-endo Shaper instrument (FKG Dentaire, La Chaux-de-Fonds, Switzerland) during the removal of root fillings from oval-shaped canals. M-Wire Reciproc and Reciproc Blue systems (VDW, Munich, Germany) were used as reference instruments for comparison, and micro–computed technology was used as an analytical tool.

Methods

Thirty mandibular incisors with oval-shaped canals were matched based on similar anatomic features of the canal (eg, volume, aspect ratio, and 3-dimensional configuration) after scanning procedures. The canals were prepared with M-Wire Reciproc R25 instruments and filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany) using the continuous wave of condensation technique. Then, the sample was allocated into 3 experimental groups (n = 10) according to the retreatment protocol used: M-Wire Reciproc, Reciproc Blue, and XP-endo Shaper. M-Wire Reciproc R25, Reciproc Blue R25, and XP-endo Shaper instruments were used to remove the root fillings. Apical enlargement was performed with M-Wire Reciproc R40, Reciproc Blue R40, and BioRace BR5 (FKG Dentaire) instruments. Each sample was scanned after each endodontic procedure. The volume of remaining root filling material was quantified before and after apical enlargement. The percentage volumes of root filling reduction in relation to the instrumented canals at both time points (before and after apical enlargement) were calculated and considered for statistical analysis. Data were analyzed statistically with a significance level of 5%.

Results

Reciproc Blue presented significantly lower removal of filling material compared with the XP-endo Shaper (Tukey test, P < .05). No difference was detected either between M-Wire Reciproc and Reciproc Blue (Tukey test, P > .05) or M-Wire Reciproc and XP-endo Shaper (Tukey, P > .05). The increase of apical enlargement significantly improved the removal of root fillings from the root canals (P < .05); this effect was similar for all systems (time point × file system, P > .05).

Conclusions

The XP-endo Shaper instrument showed a higher percentage of root filling removal, but no differences were observed comparing M-Wire Reciproc with the XP-endo Shaper or Reciproc Blue. The increase of apical enlargement improved the removal of root fillings in all groups. None of them was able to render root canals completely free from root fillings.

Section snippets

Sample Size Calculation

An estimation of the minimal sample size to observe differences among the experimental groups was based on the study by De-Deus et al4, in which an effect size of 2.13 was calculated and input into an analysis of variance test from the F family together with an alpha-type error of 5% and power beta of 95% (G*Power 3.0 for Machintosh; Heinrich Heine, Universitat Dusseldorf, Dusseldorf, Germany). The output indicated a minimum sample size of 3 roots per group to observe significant differences

Results

Preliminary baseline statistical evaluation (Table 1) revealed a significant uniform distribution of the samples among the groups both before (volume, P > .05; surface area, P > .05) and after canal instrumentation (volume, P > .05; surface area, P > .05).

A generalized linear model for repeated measures indicated a borderline significance for the influence of the file systems over the percentage of removed root fillings (P < .05), with Reciproc Blue presenting significantly lower removal of

Discussion

The XP-endo Shaper instrument showed superiority over the Reciproc Blue instrument (P < .05) in the first step of root filling removal. Therefore, the first hypothesis tested was denied. Previous studies have assessed some outcomes of XP-endo Shaper instruments, such as shaping ability, debris extrusion, and intracanal bacterial reduction6, 8, 10, 11, 12, 17. However, only 1 of them evaluated its effectiveness during root canal retreatment6; using CBCT images, it was shown that the XP-endo

Conclusions

Under the conditions of the current study, it can be concluded that the XP-endo Shaper instrument showed a higher percentage of root filling removal, but no differences were observed comparing M-Wire Reciproc with the XP-endo Shaper or Reciproc Blue. The increase of apical enlargement improved the removal of root fillings in all groups. However, none of them was able to render root canals completely free from root fillings.

Acknowledgments

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

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