Objectives: This study was conducted to examine the effect of conditioning protocols on shear bond strength of viscous glass-ionomer cement (GIC) Versus resin-modified glass-ionomer cement (RMGIC) to dentin.
Materials and methods: Forty caries free permanent molars were used. They were sectioned mesiodistally into two halves to obtain 80 specimens that were divided into eight groups (n=10) according to the conditioning protocol. In Group 1 and 2: Dentin was preconditioned with 10% polyacrylic acid either for 10 or 20 seconds and bonded to viscous glass ionomer (Fuji IX GP Extra) using a specially constructed mold (2 mm diameter X 3mm height). In Group 3 and 4: Preconditioning was followed as in group 1 and 2 but RMGI (Fuji II LC) was used. However, in group 5 and 6, dentin was preconditioned with 37% phosphoric acid either for 10 or 20 seconds followed by packing of viscous GI. Group 7 and 8: Preconditioning was done as previous followed by application of RMGI. The specimens were placed in a universal testing machine (Model 3345, Instron Corp., Canton, Mass., USA) with a cross head speed 0.5 mm/min and subsequently tested for shear bond strength SBS (MPa). Statistical analysis was done by using ANOVA and independent t test.
Results: SBS values revealed higher bond strength values for RMGI in comparison to viscous GI. Polyacrylic acid groups exhibited higher values than those of phosphoric acid. There was no significant difference in bond strength values of specimens conditioned by the two conditioners for either 10 or 20 seconds(P ≤ 0.05).
Conclusions: RMGI experienced high SBS values to dentin. The effect of acid used for dentin conditioning prior to viscous and RMGI can not be overemphasized.