Purpose: To investigate the effects of different combinations of self-adhesive resin cements and surface treatments on the microtensile bond strength (μTBS) of different CAD/CAM resin-matrix ceramics.
Materials and methods: Two different types of CAD/CAM resin-matrix ceramics (LAVA Ultimate [LU] and Vita Enamic [VE]) were used. Slices 5 mm in thickness were obtained from each CAD/CAM material. Samples of each ceramic were randomly separated into the following surface treatment groups: (1) Control group with no surface treatment; (2) 9.5% hydrofluoric acid (HF) + universal adhesive (UA, Single Bond Universal, 3M ESPE); and (3) Sandblasting with 50-μm aluminum oxide particles (SN) + UA. Two different types of recently developed resin cement (RelyX U200, 3M ESPE; SET PP, SDI Dental Limited) were applied to the treated ceramic slices in each group. After 24 hours, parallel sections were removed from the specimens, and microbeam-shaped sticks (1.0 × 1.0 × 10 mm) were prepared. The μTBS test was performed, and the data were statistically analyzed.
Results: Statistical analyses revealed differences among the study groups (P < .05). The control groups of each resin cement exhibited lower μTBS values than the groups that received surface treatment (P < .05). The effect of surface treatment on μTBS (partial eta-squared [ηp2] = 0.381) was more significant than the effects of ceramic (ηp2 = 0.267) and self-adhesive resin cement (ηp2 = 0.184).
Conclusion: Surface treatment is the most important factor affecting the μTBS of resin cement to CAD/CAM materials, followed by the type of resin-matrix ceramic and the type of resin cement, respectively.