Effect of powder/liquid ratio of glass ionomer cements on flexural and shear bond strengths to dentin

Aim: This study evaluated the effect of varying the powder/liquid (P/L) ratio on the shear bond to dentin (SBS) and flexural strength (FS) of glass ionomer cements (GIC)s. Methods: Three types of GICs (Fuji II, Fuji II LCi and Fuji IX GP) were mixed using the following P/L ratios: 20% lower than the manufacturer's ratio, manufacturer's ratio, 20% higher than the manufacturer's ratio (9 groups). SBS (MPa) was evaluated and the mode of failure checked under stereomicroscope. FS (MPa), of the specimens (25×2×2mm) assessed using a universal testing machine at a crosshead speed of 1 mm/min. The data were subjected to two-way ANOVA and Tukey's test for analysis (p< 0.05). Results: The highest SBS and FS (MPa) obtained for Fuji II, Fuji II LCi and Fuji IX were 6.12±2.11 and 16.96±2.73; 11.60±3.19 and 49.58±8.75; 7.39±2.77 and 20.32±2.09, respectively. The interaction between materials and P/L ratios had no significant effect on the properties tested in this study. Fuji II LCi exhibited significantly higher SBS and FS than the other two GICs in all P/L ratios. Conclusions: No significant differences were observed between Fuji II and Fuji IX. Twenty percent variation in P/L ratio had no significant effect on SBS and FS of GICs.