Initial tensile bond strength of resin-modified glass ionomers and polyacid-modified resins on perfused primary dentin

The objective of this study was to evaluate the initial tensile bond strength of a resin-modified glass ionomer (Photac(R)-Fil) and two polyacid-modified composite resins (Compoglass(R), Dyact(TM)) to primary dentin. A hybrid composite resin (Tetric(R)) and two chemical cured glass ionomers (BaseLine(R), Hi-Dense(R)) served as controls. Ninety caries-free dentinal discs were ground flat and perfused with Ringer's solution. Dentinal surfaces were conditioned (except for BaseLine(R)). From each material, fifteen standardized specimens were attached to the dentin. Light-curing of the respective materials followed (1 min), and adhesion was tested with a universal testing machine 15 min after application. The highest initial bond strength was observed with Tetric(R) (5.17 MPa). Closed test procedure (Kruskal-Wallis) showed significant differences between all materials (P < 0.05), except for Compoglass(R) (1.82 MPa) vs. Dyract(TM) (2.35 MPa), and BaseLine(R) (0.37 MPa) vs. Photac(R)-Fil (0.42 MPa). The condensable glass ionomer Hi-Dense(R) revealed a mean tensile bond strength of 0.19 MPa. Adhesion of (polyacid-modified) composite resins is superior to the other tested glass ionomer. materials, when applied to perfused primary dentin.