Combination of a self-etching adhesive and a resin-modified glass ionomer: effect of water and saliva contamination on bond strength to dentin.

Abstract

Because studies have shown that adherence to dentin of resin-modified glass ionomers (RMGI) can be improved by surface treatment with a self-etching adhesive (SEA), the purpose of this in vitro study was to evaluate the water and saliva tolerance of this combination before and after application of SEA. Seventy cylinders of an RMGI (Fuji II LC) were bonded to the dentin of human teeth: 10 without any surface treatment, 10 after polyalkenoic acid conditioning, 10 after application of SEA, 10 after application of SEA on water contaminated dentin, 10 after application of SEA on saliva contaminated dentin, 10 on water contaminated light-cured SEA, and 10 on saliva contaminated light-cured SEA. The shear bond strength (SBS) was determined in a universal testing machine and the site of bond failure recorded. A Kruskal-Wallis test was performed followed by Games-Howell post-hoc pairwise comparison tests on the SBS results (p < 0.05), and a chi-square test was used for the fractographic analysis (p < 0.05). The lowest SBS was obtained without conditioning (5 ± 1 MPa). Polyalkenoic acid improved SBS (8 ± 2 MPa) and SEA increased it very significantly (15 ± 2 MPa), even in the case of water contamination (16 ± 2 MPa before application of SEA, 21 ± 4 MPa after application of SEA), or saliva contamination (20 ± 7 MPa before application of SEA, 19 ± 6 MPa after application of SEA). The group bonded without conditioning resulted in only adhesive fractures, showing a statistically significant difference from the other groups. SEA in association with the Fuji II LC RMGI increased the SBS very significantly, even in the case of water or saliva contamination.