comparative evaluation of smear layer removal by using different Er: YAG lasers parameters: An <i>İn-vitro</i> scanning electron microscopic study

Abstract

Introductıon: The purpose of this in‑vitro study was to investigate the effect of irrigation activation methods using different laser parameters on microhardness and push‑out bonding strength of root canal dentin. This study evaluates and compares the efficacy of different laser parameters in smear layer removal using the scanning electron microscopic image analysis.

Materials and Methods: In this in‑vitro study, 60 newly extracted human teeth with extraction indications were used. Later, the teeth were randomly divided into three groups (n = 20). In Group 1, irrigation was performed using 2 Er:YAG laser (Fotona Laser AT Fidelis Plus III, Slovenia) with 0.6 W, 15 Hz, and 40 mJ parameters. In Group 2, irrigation was performed at 0.3 W, 15 Hz, and 20 mJ. In Group 3 (control group), conventional syringe irrigation method was performed without activation. After irrigation activation, horizontal sections were taken from the teeth, sections from the coronal, middle, and apical triplets were selected and subjected to the Vicker’s microhardness test. The Kruskal–Wallis and Wilcoxon signed‑rank tests were performed on the obtained data.

Results: There was no statistically significant difference between the control group and the laser group (P > 0.05). As a result of the push‑out bonding strength test performed on the coronal and apex regions of laser treated and untreated groups, the values of the coronal region were found to be higher than the apex region, and it was found that the bonding strength of the coronal part of the laser group was increased (P < 0.05). The change in parameters between the laser groups did not produce a statistically significant difference between the groups (P > 0.05).

Conclusion: According to this study the laser group increases the bonding strength without a negative change in microhardness. In this study the further research is needed on this subject.

Keywords: Laser, microhardness, photon-induced photoacoustic streaming, push‑out, scanning electron microscopic