Bond strength of glass-ionomer cements to caries-affected dentin

The aim of this study was to assess the tensile bond strength of a resin-modified glass-ionomer cement (a: Fuji II LC) and three traditional glass-ionomer cements (b: Ketac-fil; c: Ketac Molar; d: Fuji IX) to caries-affected dentin.

Forty human permanent molars with occlusal caries in dentin were selected, embedded in polyester resin, and ground until the carious dentin was exposed. Infected dentin was removed with curettes according to the atraumatic restorative technique (ART), and the tooth surface was smoothed with SiC paper. A bonding site, limited to 3 mm in diameter, was treated with polyacrylic acid for 10 s. After surface treatment, an inverted glass-ionomer cone was prepared for each specimen, using a split bisected Teflon matrix. The cones were immediately protected with a thin layer of nail varnish or bonding agent. Specimens were stored in distilled water at 37 degrees C for 24 h, and then bond strength to failure was tested.

The mean (SD) bond strengths in MPa were: a: 8.33 (2.35); b: 2.46 (1.60); c: 0.83 (1.18), and d: 1.45 (1.70). The data were analyzed using ANOVA and Tukey statistical tests. Fuji II LC, a resin-modified glass-ionomer cement, showed higher bond strength values and was statistically superior to the other groups, containing traditional glass ionomer cements (p < 0.05).

Findings showed that the traditional glass-ionomer cements tested in this study had lower mean bond strength values to caries-affected dentin than did the resin-modified glass-ionomer cement.