Introduction: The final result of a rehabilitation is determined by the color and thickness of the ceramic, by the cement and by the color of dental substrate. Fluorescence consists of a spontaneous emission of visible light in the blue spectrum after absorption of light in the ultraviolet spectrum. Objectives: To evaluate in vitro the fluorescence changes of feldspathic ceramic when used with different flowable resins. Materials and methods: Sixty samples of A2 colored feldspathic ceramic with two different thicknesses were produced. As a substrate, 60 discs of composite resin were produced. The samples were cemented and adhered to the composite resin with 2 flowable resins. The results of the fluorescence spectra were obtained with a spectrofluorometer. For statistical analysis we used the two-way ANOVA, with p 0.05. Results: The group with the highest fluorescence emission is the group cemented with G-aenial Flo A3, thickness of 0.5 mm, with a value of 2.47E06 a.u. The group with the lowest fluorescence emission intensity is the group cemented with G-aenial Flo A2, thickness 0.8mm, with a value of 1.59E06 a.u. Discussion: The fluorescence emission intensity of the flowable resins may influence the final behavior of the ceramic restoration. The thickness of the ceramic influences the fluorescence. Conclusions: Different cements have different fluorescence emissions. Clinical Implications: The optical properties of the cements are as important as those of ceramics. The aesthetics of a ceramic restoration depends on the type of cement used. Schlagwörter: Fluorescence, ceramics, flow resins, oral rehabilitation