Nanoleakage for Self-Adhesive Resin Cements used in Bonding CAD/CAD Ceramic Material to Dentin

OBJECTIVES To determine nanoleakage of CAD/CAM ceramic blocks bonded to dentin with self-adhesive resin cement. METHODS Eighteen sound extracted human molars were sterilized and sectioned into 3 mm-thick dentin sections. Trilux Cerec Vitablocks (Vita) were also sectioned into 3 mm sections, surface-treated using 5% hydrofluoric acid-etchant, and then coated with silane primer (Vita). Trilux and dentin sections were cemented together by means of three resin cements: Rely-X Unicem (3M/ESPE), BisCem (Bisco), and Calibra (Dentsply), according to manufacturers' recommendations. Calibra was used in conjunction with Prime/Bond-NT adhesive (Dentsply), while the other two are self-adhesive. The bonded specimens were stored for 24h in distilled water at 37°C. Specimens were vertically sectioned into 1 mm-thick slabs, yielding up to six per specimen. Two central slabs were randomly chosen from each specimen making up the cement groups (n=12). Each group was subdivided into two subgroups (n=6), a control and a thermocycled subgroup (5-55°C) for 500 cycles. Slabs were coated with nail polish up to 1 mm from the interface, immersed in a 50% silver nitrate solution for 24h, and tested for nanoleakage using Quanta Environmental SEM and EDAX. Data were statistically analyzed using two-way ANOVA and Tukey's post-hoc tests. RESULTS Rely-X Unicem and Calibra groups demonstrated no significant difference in the percentage of silver penetration, while the BisCem group revealed a significantly higher percentage (P≤.05). Thermocycling (500 cycles) did not have a statistically significant effect on the percentage of silver penetration (P>.05). CONCLUSIONS One self-adhesive-resin cement demonstrated a similar sealing ability when compared with a standard resin cement. Thermo-cycling did not significantly increase dye penetration under the test conditions.