Elsevier

Journal of Endodontics

Volume 41, Issue 2, February 2015, Pages 219-224
Journal of Endodontics

Basic Research
Removal of Filling Materials from Oval-shaped Canals Using Laser Irradiation: A Micro–computed Tomographic Study

https://doi.org/10.1016/j.joen.2014.09.026Get rights and content

Highlights

  • We examined the efficacy of 3 lasers in removing filling remnants after retreatment with rotary files.

  • Forty-two mandibular canine teeth were used.

  • We examined the percentage volume of the remaining filling material.

  • None of the retreatment procedures completely removed the filling materials.

  • The additional use of the lasers improved the removal of filling materials.

Abstract

Introduction

The aim of this study was to assess the efficacy of lasers in removing filling remnants from oval-shaped canals after retreatment procedures with rotary instruments using micro–computed tomographic imaging.

Methods

The root canals of 42 mandibular canines were prepared and obturated using the warm vertical compaction technique. Retreatment was performed with rotary instruments, and the specimens were distributed in 3 groups (n = 14) according to the laser device used in a later stage of retreatment procedure: Er:YAG, Er:YAG laser–based photon-induced photoacoustic streaming, and Nd:YAG. The specimens were scanned in a micro–computed tomographic device after root canal filling and each stage of retreatment at a resolution of 13.68 μm. The percentage differences of the remaining filling material before and after laser application within and between groups were statistically compared using the paired sample t test and 1-way analysis of variance test, respectively. Significance level was set at 5%.

Results

Overall, filling residues were located mainly in the apical third and into canal irregularities after the retreatment procedures. After using rotary instruments, the mean percentage volume of the filling remnants ranged from 13%–16%, with no statistical significant difference between groups (P > .05). Within groups, additional laser application had a significant reduction in the amount of the remaining filling materials (P < .05). A comparison between groups showed that Er:YAG laser application after the use of rotary instruments had a significantly higher removal of filling remnants (∼13%) than Er:YAG laser–based photon-induced photoacoustic streaming (∼4%) and Nd:YAG (∼3%) (P < .05).

Conclusions

None of the retreatment procedures completely removed the filling materials. The additional use of lasers improved the removal of filling material after the retreatment procedure with rotary instruments.

Section snippets

Sample Selection

After ethics committee approval (protocol #116/2013), 110 straight single-rooted extracted mandibular canines were initially selected on the basis of radiographs (Belmont Phot-X II; Takara Belmont Corp, Osaka, Japan) taken in both buccolingual and mesiodistal directions to detect any possible root canal obstruction. All teeth presenting apical curvature, previous endodontic treatment, resorptive defects, or more than 1 root canal were excluded. The specimens were disinfected in 0.1% thymol

Results

Table 1 summarizes the means and standard deviations of the percentage remaining filling materials of the experimental groups after the use of rotary instruments as well as additional laser irradiation. Overall, none of the retreatment procedures completely removed the filling materials from the root canals.

After using rotary instruments, the mean percentage volume of the filling residue ranged from 13%–16%, with no statistical significant difference between groups (P > .05). Despite

Discussion

Controversial results regarding the efficacy of rotary instruments on the root canal retreatment procedures can be found in the literature 6, 10 and may be explained by methodological differences among the studies such as sample selection, evaluation methods, experimental design (ie, number of files, time of the procedure, speed and torque of the motor, taper and size of instruments, and amount of irrigants), and the additional use of heat or solvents. Regarding the latter, no solvent was

Conclusions

Under the limitations of this ex vivo study, neither retreatment protocols were able to render root canals free of root filling remnants. The additional use of lasers improved the removal of filling materials after canal retreatment with rotary instruments.

Acknowledgment

Supported by the Scientific and Technological Research Council of Turkey–TUBİTAK (grant no. 114S052).

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

References (30)

  • A. Lloyd et al.

    Elimination of intracanal tissue and debris through a novel laser-activated system assessed using high-resolution micro-computed tomography: a pilot study

    J Endod

    (2014)
  • Z. Mohammadi

    Laser applications in endodontics: an update review

    Int Dent J

    (2009)
  • J.F. Siqueira

    Reaction of periradicular tissues to root canal treatment: benefits and drawbacks

    Endod Topics

    (2005)
  • D.K. Rechenberg et al.

    Impact of cross-sectional root canal shape on filled canal volume and remaining root filling material after retreatment

    Int Endod J

    (2013)
  • T. Taşdemir et al.

    Efficacy of three rotary NiTi instruments in removing gutta-percha from root canals

    Int Endod J

    (2008)
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