RESUMO
Introduction: Laser technology is gaining increasing importance in dental practice and also in the field of Endodontics with its ability to promote disinfection and experimentally in the preparation of root canal. The action of different types of lasers results in changes representing the increase in permeability of dentinal tissue (Er: YAG) or sometimes by a decrease in melting and recrystallization of dentin (Nd: YAG). Objective: this study assessed through apical dye leakage, the influence of irradiation with two types of laser, regarding to the quality of apical sealing of endodontic fillings. Material and methods: Thirty-six single-rooted teeth were used after being prepared with the ProFile system up to size #40 instrument and then divided into four experimental and two control groups. The technique used previously to the filling was as follows: G1 - not irradiated; G2 - irradiated with Er: YAG; G3 - irradiated with Nd: YAG and G4 - irradiated with Er: YAG followed by Nd: YAG. After external waterproofing and dry, the specimens were filled with a cold vertical condensation technique, using AH Plus sealer, and immediately immersed into 0.5% methylene blue solution for subsequent cleavage. The linear values of apical marginal leakage were obtained with the aid of an optical microscope connected to a computer using the Image Lab® software. Results: Data analysis showed the non-existence of statistically significant (p = 0.05) differences between different groups. Conclusion: It was concluded that the laser does not have influence on the apical sealing.