Effect of different cleaning methods after surface treatment of dental ceramics on the surface characteristics and adhesion to resin-based luting agents

The aim of this study was to assess the efficacy of cleaning methods after the surface treatment of dental ceramics. Ceramic slabs (zirconia – Yz; lithium disilicate-reinforced glass – Ld; and porcelain – Pc), were submitted to different surface treatments (air abrasion for Yz and hydrofluoric acid etching for Ld and Pc), and after, six cleaning methods were tested: DW – distilled water for 60 s; AL – 70% alcohol for 60 s + DW; UDW – ultrasonic bath with distilled water for 60 s; UAL – ultrasonic bath with 70% alcohol for 60 s + DW; IVC – ivoclean for 20 s + DW; PAC – 37% phosphoric acid for 20 s + DW. Microshear bond strength to luting agent was tested after 24 h (baseline) or 6 months storage (aged) in water at 37 °C. Complementary analysis of failure pattern, surface topography and composition, and contact angle measurements were executed. The cleaning methods promoted similar bond strength for Ld and Pc, regardless of the condition (baseline and aged) and for Yz after aging. DW, AL, and PAC decreased the contact angle for Yz, while UAL decreased for Ld. Pc presented a higher wettability with UDW, UAL, and PAC. The use of IVC and PAC resulted in precipitates in the Pc surface. For Yz, more air-abrasion remnants were observed using DW; for both Ld and Pc, a higher presence of fluorine was observed in groups treated with IVC. Despite differences in surface composition, topography and contact angle measurements, after aging the bond strength to the tested ceramic materials was similar regardless of the different cleaning methods.