Alternative surface treatments strategies for bonding to CAD/CAM resin-matrix ceramics

This study evaluated the shear bond strength (mu SBS) and failure mode of CAD/CAM polymer-infiltrated ceramic network (PICN - Vita Enamic) and nanoceramic resin (NCR - Lava Ultimate) submitted to alternative surface treatments. 40 plates of each material were submitted to (n = 10) conventional (manufacturer's indications): Sandblasting with Al2O3 (SAND) and 5% hydrofluoric acid etching (5% HF), or alternative treatments: 10% HF (10% HF) and Sandblasting + silanization (SAND/SIL). A self-etching adhesive system (Scotchbond Universal Adhesive, 3M Oral Care) was applied, and resin cement cylinders were built on the specimen's treated surface and tested in mu SBS after 24 h, or after water storage for 1 year. Data were evaluated by three-way repeated-measures ANOVA and Tukey test (alpha = 0.05). Failure mode was evaluated under scanning electron microscopy (SEM). At 24 h, HF etching (5% or 10%) promoted higher mu SBS for PICN, while SAND and 5% HF promoted higher mu SBS for NCR than SAND/SIL (p > 0.05). After storage for 1 year, all treatments decreased PICN's bond strength, but 10% HF exhibited higher mu SBS than 5% HF (p < 0.05). Also, 5% HF and SAND/SIL maintained mu SBS of NCR, and in general, NCR exhibited higher mu SBS than PICN. Failure mode was predominantly mixed after 24 h and mostly adhesive after 1-year storage. In conclusion, the surface treatments influenced the bond strength of PICN and NCR and 1-year storage decreased the bond strength for most groups. 10% HF is the treatment option for PICN while 5% HF-etching is an alternative to sandblasting for NCR.