Nd:YAG laser effects on the microleakage of composite resin restorations

Objective: This study evaluated microleakage of composite restorations submitted to marginal treatment with Nd:YAG laser and surface sealant. Background Data: Previous studies have demonstrated that Nd:YAG-lased enamel melted and became recrystallized with a morphologic appearance similar to lava, and has been used clinically in the sealing of enamel pits and fissures. Methods: Class V cavities in enamel of human premolars were restored with composite resin (Z100, 3M) and randomly divided in six groups: G1, control; G2, surface sealant marginal treatment; G3 to G6, were treated with pulsed Nd:YAG laser (1.064 mu m) marginal treatment, contact fiberoptic (300 mu m), air cooling, for 30 seconds, powers of 1.2-2 W, repetition rates of 20-30 Hz, energies of 40-100 mJ. Teeth were impermeabilized, immersed in a rhodamine dye, sectioned, and evaluated under stereomicroscope microscopy with scores. Results: There were significant differences between marginal treatments; there were no differences between groups 1, 2, and 4, and 3, 5, and 6; lower values of microleakage were at groups 3, 5, and 6 (Kruskal-Wallis, p = 0.05). Conclusion: Nd:YAG laser showed improved marginal sealing and decreased microleakage of composite resins restorations.