The Effect of Er:YAG and Nd:YAG Lasers on Microtensile Bond Strength of a Sixth-Generation Two-Step Adhesive

Previous studies have revealed the effectiveness of laser therapy in the improvement of dentin bonding. In other words, laser radiation can result in the higher bond strength of adhesives. Accordingly, the aim of this study was to propose an appropriate protocol for the use of Er:YAG and Nd:YAG lasers with the purpose of improving the bond strength of a sixth-generation two-step adhesive.
In this experimental study, a total of 70 healthy extracted teeth were selected and classified into seven groups. The control group was prepared according to the manufacturer's instructions. The remaining six groups were treated with Er:YAG and Nd:YAG lasers before primer application (Er-BP and Nd-BP groups), after primer application (Er-AP and Nd-AP groups), and after bonding (Er-AB and Nd-AB groups). The specimens were covered with Filtek Z-250 resin composite (shade A2 and height of 4 mm), using an incremental technique and were then treated. Following that, the microtensile test was performed on the samples. The gathered data were analyzed, using one-way analysis of variance (ANOVA), followed by post-hoc Dunnett T3 test. P-value less than 0.05 were considered statistically significant.
The mean and standard deviation of bond strength in the groups were as follows: Control= 30.09±4.21, Er-BP= 18.83±4.21, Er-AP= 14.43±3.12, Er-AB= 19.67±4.96, Nd-BP= 20.35±5.55, Nd-AP= 39.85±4.13, and Nd-AB= 18.16±3.36. The values obtained in the Nd-AP group were significantly higher than the control group (PIn the present study, use of Nd:YAG laser system after primer application (Nd-Ap) significantly improved the bond strength in comparison with the control group.