Aim: To compare the microshear bond strength of resin based composite (RBC) and resin modified glass ionomer cement (RMGIC) restorations when bonded to teeth with molar incisor hypomineralisation (MIH).
Methods: Eleven first permanent molars with MIH were included in this study. Teeth were sectioned mesio-distally producing a total of 22 surfaces for testing. Each specimen was placed inside a plastic ring with the flattened surface in contact with a glass slab. The plastic ring was filled with autopolymerising acrylic resin to imbed the specimen leaving the enamel surface exposed. Each surface was then bonded to 0.96 mm diameter RBC and light cured RMGIC following the manufacturers' instructions. Microshear bond testing was performed after 24 h storage in distilled water at 37 °C. A Bisco shear tester was used to apply shear stress of 1 mm/min until failure. Wilcoxon signed-rank paired-test was used for comparison of bond strength values.
Results: Microshear bond strength of RBC (30.80 ± 8.19 MPa) was significantly higher than that of RMGIC (11.13 ± 6.91 MPa) when bonded to hypomineralised permanent first molars (p < 0.001).
Conclusion: The microshear bond strength of RBC is significantly higher than that of RMGIC when bonded to MIH affected teeth. Therefore, RBC can be recommended as the restoration of choice for teeth with MIH whenever the clinical scenario allows.
Keywords: Bond strength; Enamel; Molar incisor hypomineralisation; Resin composite; Resin modified glass ionomer.