Effects of Different Er:YAG Laser Parameters on Debonding Forces of Lithium Disilicate Veneers: A Pilot Study

Abstract Objectives:The aim of this study was to investigate the effects of different Er:YAG laser application parameters on shear bond strength values of all-ceramic restorations cemented to different tooth surfaces. Materials and Methods:Thirty lithium disilicate ceramic disc specimens (thickness of 1 mm and diameter of 3 mm) were fabricated and cemented by using a dual-cure resin cement to 30 non-carious, extracted mandibular incisors, which were divided into 2 as; tooth reduction on enamel and on dentin. Six test groups (n=5) were designed according to the application method; 1st group on enamel and without laser application, 2nd group on dentin and without laser application, 3rd group on enamel and laser applied (600mJ, 2 Hz), 4th group on dentin and laser applied (600mJ, 2 Hz), 5th group on enamel and laser applied (165mJ, 30 Hz), 6th group on dentin and laser applied (165mJ, 30 Hz). The Er:YAG laser was applied on each specimen for 3 seconds. After the laser application, all groups were subjected to shear bond strength test until fracture. The failure modes were also examined. The data were statistically analyzed by using one-way ANOVA and post hoc T-test at a 0.05 level of significance. Results:According to one-way ANOVA test, there was statistically significant differences between the groups (p<0.05). Post hoc T-test revealed no statistically significant difference only between the groups 2 and 5. The mean shear bond strength of the specimens of group 1 was statistically higher than that of all the other groups (p<0.001). Conclusion:Er:YAG laser-irradiation is a successful and effective application in removing ceramic veneers. When the depth of the tooth reduction amount increases, parameters such as; the frequency and energy of the laser application can be reduced for restorations with the same thicknesses