Evaluting Different Powers of Nd:YAG Laser Irradiation on Dentine Microtensile-bond-strength

Objectives: Bonding agent study is one of the most controversial issues in restorative dentistry. The aim of this study was to evaluate different powers of Nd:YAG laser irradiation on dentine microtensile bond strength(MBS) of Universal adhesive systems by using Etch&Rinse technique.
Methods: 25 healthy premolar human teeth randomly divided into 5 groups: control: etch+bond /L0.5: etch+ bond+ Nd:YAG laser(0.5W) /L0.75: etch+bond+ Nd:YAG laser(0.75W) /L1: etch+bond+ Nd:YAG laser(1W) /L1.5: etch+bond+ Nd:YAG laser(1.5W) (Laser irradiation applied on unpolymerized bond in all laser groups). Composite resin build-ups were made for all groups, then teeth were sectioned to obtain Stick Form specimens (1.0 mm2). The microtensile test was performed, yielding bond strength values in MPa, which were evaluated by One-way ANOVA followed by Tukey's tests (p < 0.05) for individual comparisons.
Results: The lowest MBS was seen in control group(16.39±1.89) and L1 group shows the highest MBS(29.3 ±4.03). Groups with Nd:YAG laser irradiation promoted significant increases in bond strength values than control group.
Conclusions: Nd:YAG laser irradiation after adhesive application and prior to polymerization, significantly promotes MBS of a single Universal adhesive system to dentin. The optimum power of Nd:YAG laser irradiation to improve the MBS was 1W.