Effect of Mdp-containing Silane/adhesive on Bonding to Zirconia

Objectives: To evaluate (1) the effect of 10-MDP (MDP) in the composition of silane; and (2) the use of combined silane/universal adhesive in the same solution or in separate solutions on the immediate (24h) microshear bond strength (μSBS) to 3Y-TZP [ZR].
Methods: 30 ZR CAD/CAM blocks were cut into 4 rectangular sections, and processed as recommended by the respective manufacturer. The ZR specimens were assigned to 12 groups (n=5): silane coupling agent (no silane; silane without MDP [MBS, Monobond S]; Silane with MDP [MB⁺, Monobond Plus]); and adhesive system + resin cement (no adhesive + Enforce [ENF]; no adhesive + RelyX Ultimate [RXU]; Prime & Bond Elect [PBE] + ENF; Scotchbond Universal Adhesive [SBU] + RXU. After each treatment, cylinder-shaped transparent matrices were filled with the respective resin cement and light cured. Specimens were stored in water (37°C/24 h) and tested in μSBS (1.0 mm/min). The mSBS data were analyzed using two-way ANOVA and Tukey’s test (a = 0.05).
Results: The use of either cement without adhesive or silane resulted in the lowest mean μSBS (p < 0.0001). The use of MB⁺ silane alone resulted in higher mean μSBS than those of other groups (p < 0.0001). The use of SBU alone or associated with MB⁺ silane resulted in higher mean mSBS compared with MBS silane groups (p < 0.001).
Conclusions: The use of an MDP-containing silane alone or associated with an MDP-containing universal adhesive resulted in the highest mean bond strengths to ZR at 24h. Long-term water storage testing is currently underway to test the stability of the bondings.