Bond strength of glass–ceramics on the fluorosed enamel surfaces

Objectives Effect of different adhesive luting systems on the shear bond strength of IPS Empress 2 ceramic restorations to fluorosed enamel surface was investigated. Methods Forty-eight ceramic discs (2 mm × 3 mm; IPS Empress 2) were fabricated. Twenty-four non-carious extracted human molar teeth with fluorosis and 24 without fluorosis were cleaned with pumice using a plastic brush and then they were divided into two main groups. The IPS Empress 2 ceramic discs were luted to the teeth of four subgroups with two different adhesive luting systems, Variolink 2/Excite DSC (etch-and-rinse) and Clearfil Esthetic Cement/ED Primer II (self-etch), thermocycling was performed 5000 times. Shear bond strengths were tested using Shimadzu Universal Testing Machine until failure. An optical microscope and image analyzer were used at 10× and 1000× magnification to analyze the surfaces for adhesive, cohesive and mixed failure percentages. Data was analyzed with one-way ANOVA and Tukey test at a significance level of p < 0.05. Results Mean shear bond strength data of the groups in MPa were; Variolink 2/Excite DSC on fluorosed enamel: 18.3 ± 3.08, Variolink 2/Excite DSC on non-fluorosed enamel: 18.79 ± 2.65, Clearfil Esthetic Cement/ED Primer II on fluorosed enamel: 8.43 ± 2.45, Clearfil Esthetic Cement/ED Primer II on non-fluorosed enamel: 13.53 ± 1.68. Mixed failure was the most prevalent type of failure in moderate fluorosed and non-fluorosed teeth with etch-and-rinse dentin bonding system, and in fluorosed teeth with self-etch dentin bonding system. Conclusions The use of an etch-and-rinse adhesive luting procedure produced higher bond strengths of glass–ceramics bonded to fluorosed and non-fluorosed enamel surfaces than the self-etch bonding system.