Efficacy of Smear Layer Removal at the Root Tip by Using Ethylenediaminetetraacetic Acid and Erbium, Chromium: Yttrium, Scandium, Gallium Garnet Laser

IntroductionThe purpose of this study was to compare the efficacy of laser-driven irrigation in removing the smear layer and debriding the apical region of the root canal (the root tip) with that of ultrasonic irrigation.MethodsForty extracted human teeth with straight single roots were randomized into 4 groups (n = 10). The specimens were shaped by using hand instruments up to a size 30/.02 file (Control, Laser 1, and Laser 2 groups) or a size 20/.02 file (Laser 3 group). During instrumentation, each canal was irrigated with 3% NaOCl and 17% ethylenediaminetetraacetic acid alternately between the use of successive files. The 4 groups of 10 teeth were processed as follows. In the Control group, teeth were irrigated with 17% ethylenediaminetetraacetic acid, and the irrigant was activated with an ultrasonic device for 60 seconds. In the Laser 1 and Laser 3 groups, the irrigant was activated with the laser for 60 seconds. In the Laser 2 group, the irrigant was activated with the laser for 30 seconds.ResultsThere were significant differences between the smear layer and debris scores for the Laser 1 group and those for the Control (P < .001), Laser 2 (P = .002), and Laser 3 groups (P = .012 and P = .013, respectively). Completely clean root canals were found in the Laser 1 group.ConclusionsUse of a laser with a plain fiber tip, which produces cavitation in the irrigant, has potential as an improved alternative method for removing of the smear layer from the apical region of a straight root canal.