Endodontic retreatment of curved root canals using the dual wavelength erbium, chromium:yttrium, scandium, gallium, garnet, and diode 940-nm lasers and the XP-Endoshaper/finisher technique

Abstract

PurposeThe aim of this quantitative study was to compare between a dual-wavelength laser (Er,Cr:YSGG, diode 940 nm) to the XP-Endoshaper/finisher combined with ethylenediaminetetraacetic acid (EDTA) 17% technique in removing secondary smear layer created during endodontic retreatment of curved canals.MethodsTwenty-four human curved root canals were endodontically prepared and filled with AH-sealer and Reciproc® Gutta percha cones. The fillings were removed after 6 weeks, and the samples were randomly divided into 3 groups: A, negative control: irrigated with distilled water; B, XP-Endoshaper/finisher with EDTA 17%; and C Er,Cr:YSGG (2 W, 20 Hz, 50 μs) and diode 940 nm (2 W, 50% duty cycle). The canals were split longitudinally, and a laser scanning microscope (VK-X100K, VK-X200K, Keyence, Osaka, Japan) was used to capture images with the magnification of × 1000 from the canals. The images were scored by three blinded dentists using the Hülsmann scoring system, and a statistical analysis was carried out.ResultsA significant difference between the apical regions of groups B and C (p = 0.0010) was observed, with group C showing a cleaner apical region. However, this difference is cancelled out when comparing all areas of the canals (t = 1.43, df 21 p = 0.1663).ConclusionWithin the limitations of this study, it can be concluded that a dual laser wavelength protocol (Er,Cr:YSGG (2 W, 20 Hz, 50 μs) and diode 940 nm (2 W, 50% duty cycle) may be positive in removing the secondary smear layer formed during endodontic retreatment cases of curved root canals.