In Vitro Effect of Nd:YAG and Diode in MTA Microleakage

Objectives: the aim of this in vitro study was to evaluate the influence of previous irradiation of Nd:YAG and Diode lasers in the microleakage of MTA retrofill. Methods: 15 unirradicular human teeth were shaped, filled and apicectomized with FF diamond drill, where a retrograde cavity with ultrasonic tip was made. All aprocedures and irradiations were made inside a prepared device that simulates a bony cavity. The specimens were divided into 3 groups: G1 - MTA without Laser; G2 - MTA with Nd:YAG, in the specifications: 1,5W, 15Hz, 100mJ, 10 applications of 5s with a 20s interval and 1mm of distance; G3 - MTA with Diode GaAlAs (810nm; ZAP Softlase), in the specifications: continuous pulse, 2W, 10Hz, 5 applications of 5s with a 5s interval and 0,5mm of distance. The specimens were retrobturated with MTA. After 2 days at 100% umidity, the roots were coated with 2 layers of methyl-cianoacrylate up to 1mm around the ressected apex. All the specimens were immersed in solution of rodhamine 1% for 24 hours and thorough whased for 12 hours. After longitudinal resection, all specimens were observed in the Imagelab v.2.0 software, where linear (L) and per area (A) microleakage percenteges were obtained. The values were treated in Kruskal-Wallis test, showing significant statistical diference (P<0,05). Results: the mean microleakage values were: G1L=85,72 / G1A=37,79; G2L=44,31 / G2A=5,9; G3L=49,26 / G3A=9,03. Conclusions: the Nd:YAG e Diode lasers reduced significantly the microleakage of the MTA retrofilings in the pruposed methodology.