Influence of surface treatment of glass-ionomers on surface free energy and bond strength of resin composite.

The purpose of this study was to determine the influence of surface treatment of glass-ionomer (GIC) on bond strength of resin composite and surface free energies. Specimens were prepared and divided into three groups as follows: without pretreatment (control), phosphoric acid etching, and air-abrasion. Adhesive was applied and resin composite was bonded. For conventional GIC, acid etching or air-abrasion increased bond strength (8.5-8.8 MPa) when compared with controls (4.7 MPa); however, RMGIC resulted in significantly lower bond strengths (10.3-15.8 MPa) than in controls (14.2-20.5 MPa). The value of the γS(-) component increased when conventional GIC was treated with phosphoric acid or air-abrasion (60.1-60.5 mJ•m(-2)) when compared with controls (52.8 mJ•m(-2)).These results indicate that surface treatment of conventional GIC promoted higher bond strength to resin composite and higher Lewis-base components, but decreased bond strength for RMGIC.