Glass ceramics behave like selectively etched enamel on interfaces produced with self-adhesive/ self-curing resin cement

This work aimed at analyzing the bond strength of different ceramic compositions and dental substrates to a self-adhesive/curing resin cement to determine the reliability of the bonded interfaces. The study groups were Lithium Disilicate (LD), Zirconia reinforced Lithium Silicate (ZLS), Conventional Yttria-stabilized Polycrystalline Tetragonal Zirconia (Y-TZP C), Translucent Yttria-stabilized Polycrystalline (Y-TZP T), Selective Etched Enamel (E + E); unetched Enamel (E); and Dentin (D). Twenty 2 mm thick slice specimens of each group were obtained from a cutting machine, under high speed and refrigeration, followed by polishing and inclusion in PVC tubes with acrylic resin, with their flat surfaces exposed. The self-adhesive/curing resin cement was inserted in a plastic matrix on the surface of each specimen, resulting in cylinders with an internal 1.40 mm diameter x 1 mm height. The specimens were subjected to microshear bond strength test. Qualitative failure analysis was performed by stereomicroscope and scanning electron microscope (SEM). Weibull statistical analysis was performed to obtain the following metrics: probability of failure, Weibull modulus (m) (reliability) and characteristic strength (σ0). The E + E group achieved the highest median value (24.88 MPa), lower probability of failure, greater reliability, and greater characteristic strength among all the study groups. ZLS presented the highest bond strength values (20.07 MPa) and characteristic strength but also the highest data variability. LD group presented greater reliability among ceramic materials. Dentin presented the lowest median (4.51 MPa) among all substrates evaluated. The adhesive failure mode was predominant among the failure types. Adhesive interfaces of glass ceramics presented higher characteristic strength, lower probability of failure and greater reliability, being similar to selectively etched enamel.