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

Objective: This study evaluated microleakage of composite restorations subm itted to marginal treatment with Nd:YAG laser and surface sealant. Backgrou nd Data: Previous studies have demonstrated that Nd:YAG-lased enamel melted and became recrystallized with a morphologic appearance similar to lava, a nd has been used clinically in the sealing of enamel pits and fissures. Met hods: Class V cavities in enamel of human premolars were restored with comp osite 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), a ir 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 rhodamin e dye, sectioned, and evaluated under stereomicroscope microscopy with scor es. Results: There were significant differences between marginal treatments ; there were no differences between groups 1, 2, and 4, and 3, 5, and 6; lo wer values of microleakage were at groups 3, 5, and 6 (Kruskal-Wallis, p = 0.05). Conclusion: Nd:YAG laser showed improved marginal sealing and decrea sed microleakage of composite resins restorations.