Incorporation of chlorhexidine in different glass ionomer cements: surface microhardness and scanning electron microscopy

Objective: To evaluate the effect of adding chlorhexidine gluconate (CHX) to resin-modified glass ionomer cement (RMGIC) liquid on surface microhardness and scanning electron microscopy (SEM). Materials and methods: Two RMGIC (Riva and Vitremer) were selected and subdivided according to CHX incorporation and storage time. CHX was incorporated into the liquid of each material at concentrations of 05%, 1% and 2%. Specimens (SP) were made with 4 mm in diameter and 2 mm in thickness and kept in saline solution at 37ºC for 2, 7 and 30 days with n=10. Then subjected to Knoop microhardness at three equidistant points on the top surface. SEM microscopy was performed after 7 and 30 days. Results: Regarding the material, Riva was the most susceptible to the action of CHX in relation to microhardness. For the CHX concentration, the Riva Light Cure 2% had its surface values significantly increased. Analysis by SEM indicated more cohesive surface for Vitremer for all conditions evaluated. Conclusion: CHX did not impair the surface microhardness properties of the studied glass ionomer cement. Vitremer showed superior behavior at most concentrations compared to Riva Light Cure. SEM showed that immersion time caused more surface changes than addition of CHX.