Investigation of the Effect of Er:Cr:Ysgg Laser 2780 nm in Comparison with xp-Endo Finisher on Root Canal Dentin Permeability and Smear Layer Removal: An In Vitro Study

The aim of this study was to assess the effect of Er:Cr:YSGG 2780nm laser in comparison with Xp-endo Finisher in elimination of smear layer in terms of root canal dentin permeability and SEM analysis. Method: twenty-eight single-rooted extracted lower premolars were instrumented up to size X4 (protaper Next, Dentsaply) and divided into two groups according to the irrigation system, first group activated by Xp-endo Finisher and second one by Er:Cr:YSGG laser 2780 nm, pulsed mode, 1.25 W. Afterward, the roots were made externally impermeable, filled with 2%methylene blue dye, divided horizontally into three segments representing the apical, middle, and coronal thirds then examined under stereomicroscope. Using analytical software, the root section area and dye penetration area were measured, and then, the percentage of net dye penetration area was calculated. Moreover, scanning electron microscope investigations were accomplished. Results The non-parametric Mann-Whitney U test was done and showed a highly significant difference between the two experimental groups over the three root thirds. Dye penetration in Erbium laser group was significantly higher over the whole root length compared to other group. Scanning electron micrographs of Erbium laser group showed a distinctive removal of smear layer with preservation of the annular structure of dentinal tubules, while Xp-endo finisher group result in uneven removal of smear layer, and the dentinal tubules appear in sickle shape which indicate that they are partially opens especially in the apical third.