Influence of different laser irradiation energy on ceramic bond strength

Objective: This study aimed to verify the influence of differentsNd:YAG laser energy parameters on the bond strength between lithium disilicate ceramic and resin cement. Methods: One hundred Lithium disilicate ceramic specimens with truncated cones shape were prepared and divided into 5 groups (n=10): 1- Control(without laser irradiation); 2- 80Nd – laser irradiation with Nd:YAG laser at 80mJ energy intensity for 1 min; 3- 100Nd - irradiation with Nd:YAG laser with an intensity of 100 mJ for 1 min; 4- 120Nd - Nd:YAG laser irradiation at 120mJ energy intensity parameters for 1 min; 5- 140Nd - Nd: YAG laser irradiation at 140mJ energy intensity parameters for 1 min. The laser irradiation on the specimen was performed in lower base of thetruncated cones shape. After all lasers treatments the groups were etched with hydrofluoric acid at 10% for 1 minute and silanized. Half of the treated ceramic specimens were cemented with resin cement (Variolink II-Ivoclar-Vivadent) to the other half resultingin hourglasses-shaped specimens.The bonded specimens were cycled thermomechanicallyand stressed to failure under tension.Data were analyzed using ANOVA and Tukey tests (α=0.05). Results: One-way ANOVAindicated that the factor “laser energy”,statistically significant differences were observed among groups (p= 0.0), The 80Nd group (21.22 ± 6.00) showed greater results means than the other groups (Control-12.37 ± 3.46; 100Nd-15.15 ± 5.89; 120Nd-14.61 ± 2.53; 140Nd-10.12 ± 4.23)(Results in MPa). The other groups, including the control, were not statistically different. Conclusions: Laser energy intensity parameter significantly affected tensile strength of the resin cement to the lithium disilicate ceramic.