Glass ionomer cements bond stability in caries-affected primary dentin

Abstract Purpose To evaluate the 2-year microtensile bond strength (μTBS) of different glass ionomer cements (GIC): high viscosity (HV), resin modified (RM) with and without nanoparticles to sound and caries-affected primary dentin. Method Thirty-six second primary molars were prepared and randomly divided into six groups (n=6) according to the combination of the main factors substrate (sound and caries-affected dentin) and GIC type (KetacTM Molar Easy Mix (KM-HV, 3M ESPE), Vitremer (VT–RM, 3M ESPE) and GIC with nanoparticles KetacTM Nano (KN-RM, 3M ESPE)). After storage for 24 h in distilled water at 37 °C, the teeth were sectioned into two halves. One half was further sectioned into beams with a cross sectional area of about 0.8 mm2 to be tested immediately under μTBS testing. The same procedure was performed in the other teeth halves after storage in distilled water for 2-year. The failure mode was assessed using stereomicroscope (400×). Data were subjected to three-way repeated measures ANOVA followed by the post-hoc Tukey's test (α=0.05). Results There was no statistical difference between sound and caries-affected dentin irrespective of the water storage time. After 2-year, only the VT-RM material showed stable bond strength values. Conclusion Water aging for 2-year does not jeopardize the bond strength of resin-modified GIC without nanoparticles to sound and caries-affected dentin of primary teeth.