Microleakage of porcelain veneer restorations bonded to enamel and dentin with a new self-adhesive resin-based dental cement

Cementation technique of bonded ceramic restorations is a time-consuming and technique-sensitive procedure critical to long-term success. Objective Evaluate the performance of a self-adhesive, modified-resin dental cement (Rely-X UniCem, 3M-ESPE) for the cementation of ceramic veneer restorations without previous conditioning of the tooth surface, and in combination with a one-bottle adhesive and a self-etching adhesive. Methods Thirty-six premolars received a veneer preparation that extended into dentin. Leucite-reinforced pressed glass ceramic (Empress 1) veneers were cemented following manufacturers’ instructions, according to the following treatment groups (n = 9): (1) Variolink–Excite Ivoclar–Vivadent (V + E control), (2) Unicem + Single Bond 3M-ESPE (U + SB), (3) Unicem + Adper Prompt L-Pop 3M-ESPE (U + AP), (4) Unicem 3M-ESPE (U). After 24 h storage at 37 °C, teeth were thermocycled (2000 cycles) at 5 and 55 °C, immersed in ammoniacal silver nitrate for 24 h, placed in a developer solution overnight and sectioned using a slow-speed saw. Three 1 mm longitudinal sections were obtained from each tooth and evaluated for leakage with a microscope (1× to 4×). Imaging software was used to measure stain penetration along the dentin and enamel surfaces. Results ANOVA with SNK (α = 0.05) revealed that on dentin, U had significantly less leakage than U + SB and U + AP, but no different than V + E; on enamel U had leakage values that were significantly greater than the groups with adhesives. Significance The self-adhesive cement U gave low leakage on dentin that was comparable to the cement that employed an adhesive for sealing dentin, whereas this cement benefits from use of an adhesive when cementing to enamel.