Apical Leakage of Three Resin-Based Endodontic Sealers after 810-nm-Diode Laser Irradiation Cacio Moura-Netto, D.D.S., M.Sc., Ph.D., 1,2 Tiago Pinto, D.D.S., 2 Harry Davidowicz, D.D.S., M.Sc., Ph.D., 2 and Abilio Albuquerque Maranha ˜ o de Moura, D.M.D., M.Sc., Ph.D. 1,2 Abstract Objective: To evaluate the influence of 810-nm-diode laser irradiation, applied before root canal filling, on apical sealing ability of three different resin-based sealers (AH Plus, EndoRez, and RealSeal). Background: Lasers have been widely used in endodontics. The dentin wall changes caused by laser irradiation could improve the sealing ability of endodontic cements. Methods: Sixty single-rooted human teeth were divided into six groups, ac- cording to the endodontic sealer used and previous 810-nm-diode laser irradiation. The protocol for laser irradiation was 2.5 W in a continuous wave, in scanning mode, with four irradiations per tooth. After sample preparation, they were analyzed according to apical leakage with silver nitrate impregnation. Results: The RealSeal sealer achieved minimum leakage rates (1.24 mm), with significant differences at the 1% level (Tukey’s test, p < 0.01) from AH Plus (1.84 mm) in nonirradiated groups. When the laser was used, there were also significant differences at the 5% level (p < 0.05) between irradiated groups (1.31 and 1.78 mm, respectively). Conclusion: The 810-nm-diode laser irradiation did not promote significant differences in apical leakage. Introduction O ne of the main objectives of endodontic therapy is to achieve a complete seal that prevents bacterial leakage and a further recontamination of root canal walls in the entire root canal system, especially in the apical region. Irrespective of the resources used for complete disinfection inside the root canal system, to ensure success, the root canal filling materials and procedures must provide a resistant sealing. 1,2 The use of laser devices such as neodymium-doped yttrium aluminium garnet (Nd:YAG) and diode lasers, have been shown to be a good auxiliary to root canal treatment because of their disin- fection capacity. 3–6 Gutknecht and colleagues 6 achieved 74% intracanal bacterial reduction using laser irradiation. In ad- dition, these two lasers have similar effects regarding mor- phological changes, causing melting and resolidification of the dentin surface 3,7–10 and improving the sealing ability of some filling materials. 11,12 There have been several studies of materials and root canal filling techniques that aim to achieve apical sealing of teeth. 13–18 Several studies of root canal sealers classify AH Plus cement (Dentsply), a hydrophobic epoxy resin-based sealer, as having the lowest apical marginal dye index, 12,15,16,18 but other authors 14,19 achieved better results regarding micro- leakage using Epiphany, a hydrophilic resin-based sealer, than with AH Plus. EndoREZ (Ultradent Products, Salt Lake City, UT) and RealSeal (SybronEndo, Orange, CA) are hy- drophilic resin sealers whose sealing properties were used on the capacity of penetration inside dentin tubules, creating resin tags. More specifically, diode laser irradiation can be used as a coadjutant to endodontic therapy. 5–11 Considering the re- moval of smear layer and morphologic changes caused by diode laser irradiation (melting and resolidification of dentin walls with partial occlusion of dentin tubules), 7–10 which may influence the sealing efficacy of root canal fillings, 11,12 an evaluation of microleakage in root canals filled with dif- ferent resin-based root canal sealers (AH Plus,EndoRez, RealSeal) previously treated with 810-nm-diode laser irra- diation seems extremely pertinent. Material and Methods After the approval of the Ethics Committee from the Den- tistry College of the University of Sa ˜ o Paulo, 60 single-rooted human teeth stored in 1% thymol solution were selected from a tooth bank for this study. After coronal access, a size 15 K- file (Dentsply Maillefer, Baillaigues, Switzerland) was in- serted into the root canal until it became visible at the apical foramen. The working length of each root canal was then 1 Department of Endodontics, University of Sa ˜o Paulo, Sa ˜ o Paulo, Brazil. 2 Department of Endodontics, University Paulista, Sa ˜ o Paulo, Brazil. Photomedicine and Laser Surgery Volume 27, Number 6, 2009 ª Mary Ann Liebert, Inc. Pp. 891–894 DOI: 10.1089=pho.2008.2308 891