Bond Strength of Self-Etching Primer to Bur Cut,Er,Cr:YSGG,and Er:YAG Lased Dental Surfaces

Objective: The purpose of this study was to evaluate the tensile bond strength of a self-etching primer system to enamel and dentin surfaces treated with Er:YAG and Er,Cr:YSGG lasers. Background Data: The recently introduced self-etching primer systems have been shown to adhere better to dental surfaces with thin or no smear layers. Moreover, there have been no previous reports on the bond strength of these adhesives to Er,Cr:YSGG laser-irradiated enamel and dentin, which have been shown to be free of a smear layer. Methods: Thirty samples of enamel and thirty of dentin were divided into three groups. The first group of each substrate served as a control with a standardized bur cut, and the other two groups were conditioned with Er:YAG (350 mJ, 10 Hz, 20 J/cm² for enamel; 300 mJ, 6 Hz, 17 J/cm² for dentin) and Er,Cr:YSGG laser (125 mJ, 20 Hz, 16 J/cm² for both substrates). After the bonding procedure, samples were restored with composite resin, and the tensile bond strength test was performed. Results: The ANOVA two-way analysis and the Tukey test at 5% significance level showed that for enamel and dentin, the bond strength values were statistically higher in Er:YAG-laser treated than in Er,Cr:YSGG-laser treated surfaces (p = 0.0001). However, bond strength means for both laser-irradiated groups were statistically lower than for the bur cut group (Er:YAG: p = 0.0281 and Er,Cr:YSGG: p < 0.0001). SEM observation of laser-irradiated surfaces revealed a roughened aspect and absence of smear layer. Conclusions: The self-etching system adhesion was influenced by the type of erbium laser used, and the bond strength was higher in the Er:YAG-laser irradiated than in the Er,Cr:YSGG-laser irradiated surfaces.