Apical microinfiltration evaluation of radicular channels irradiated with Er:YAG laser in vitro

It was evaluated, in vitro, the adaptation of the filling material (Sealer 2SR) to the root channels dentine walls treated using the endodontic technique and prepared with the Er:YAG laser, by the technique of infiltration of methylene blue dye. Using scanning electronic microscopy, the morphologic alteration of the root channel dentine was observed for one sample per studied group. Also, an evaluation of the temperature increase in the external surface of the root during the irradiations was performed for two samples per group. For each group of samples, with eleven roots each, two sub-groups had been considered: the dry, irradiated after completely dry with absorbent cones of paper, and the humid, where a cone of absorbent paper was applied for two seconds in the root canal, leaving them lightly humidified. Considering the used energies for the irradiations, the groups are: G1, control (without irradiation), G2-dry (100 mJ-10 Hz), G2-humid (100 mJ-10 Hz), G3-dry (140 mJ-6 Hz), G3-humid (140 mJ-6 Hz), G4-dry (180 mJ-6 Hz), and G4-humid (180 mJ-6 Hz). The results had shown that apical microinfiltration did not exhibit significant difference among groups. The highest increase in temperature was observed for the dry groups, with the maximum variation of temperature of 6.5 deg C. Under the scanning electronic microscopy analysis, the humid groups had presented cleaner surfaces than the dry groups. The G4-humid group presented extensive regions of fusion and resolidification of the dentine. (author)