Comparative evaluation of the effect of a resin modified glass ionomer cement universal adhesive on the shear bond strength of glass ionomer cements

The present study compared and evaluated the shear bond strength (SBS) of two types of glass ionomer cement (GIC), Riva Self Cure HVTM (SDI Ltd., Victoria, Australia) and GC Fuji IX GP EXTRATM (GC America Inc., Alsip, USA) with and without the use of Riva Bond LCTM (SDI Ltd., Victoria, Australia), a lighted cured resin-modified glass ionomer cement (RMGIC) universal adhesive. Sixty extracted sound premolars with prepared exposure of the dentine on the occlusal surface were randomly assigned into four groups according to the tested restorative materials. Shear bond strength (SBS) tests were performed by using the Shimadzu Universal Testing Machine at a crosshead speed of 0.5 mm/minute, and the values obtained were statistically analysed using one-way ANOVA and Tukey tests. The inter-group comparison showed statistically significant differences in the SBS values between all the test groups (p < 0.001). A stereomicroscope was used to assess the modes of failure. Adhesive failures were predominant in adhesive groups (>80%) compared to higher cohesive failures found in the non-adhesive groups (>86%). A Spearman's rho correlation test performed to determine the association between SBS values and mode of failures had indicated positive correlations between the adhesive failure and SBS values in the adhesive groups (rs=0.86, p<0.001; rs=0.85, p<0.001) and the cohesive failure and SBS values in the non-adhesive groups (rs=0.87, p<0.001). These findings support the improvement in adhesion of GICs to tooth structure with the use of RMGIC adhesive.