Evaluation of physical and mechanical properties of glass carbomer cement under in vitro conditions

Aim: To evaluate the microtensile bond strength (μTBS) and microhardness of glass carbomer cement in comparison to conventional glass ionomer cement and compomer. Material and Methods: The bonding strength test involved 60, second deciduous molar teeth. The dentine bonding strength of the restorative materials was evaluated by a μTBS test. Failure modes were determined by light microscopy. Plexi-glass molds of 5 × 2 mm (diameter × depth) were used for Vickers’ microhardness analysis. Seventy-five samples were evaluated, considering twenty-five samples for each material. The data were statistically analyzed by the Kruskal-Wallis test, at p≤0.05. Results:There was no significant difference between the μTBS of the glass carbomer (2.0 MPa) and glass ionomer (1.7 MPa) (p>0.05). However, the μTBSof the compomer (9.4 MPa) was higher than the glass carbomer and glass ionomer (p<0.001). No significant difference was found among the three materials, regarding adhesive, cohesive and mixed failure modes (p>0.05). The compomer presented the highest microhardness value, followed by the glass ionomer and finally, the glass carbomer (p<0.001). Conclusion:The glass carbomer cement showed a lower μTBSto the dentine than the compomer. Furthermore, the microhardness of the carbomer was lower than the compomer and glass ionomer