RESUMEN
This study was carried out to evaluate the surface microhardness and marginal integrity of a resin modified glass ionomer and a compomer after immersing them in a cola soft drink for variable periods of time. The study was conducted in two parts. Forty two standard class V cavities were prepared on extracted human premolars, restored with Dyract AP and Fuji II LC and evaluated for marginal integrity. Forty two circular discs (CDs) were prepared with Dyract AP and Fuji II LC to test microhardness. These specimens were immersed in a cola drink under low, medium and high immersion regimes. Marginal integrity was analyzed using stereomicroscope and surface microhardness was evaluated on the circular discs using a microhardness tester. Statistical analysis revealed that the marginal integrity was least affected in low and medium immersion regimes and highly affected under high immersion regime. Surface microhardness was least affected in low immersion regime, while, medium and high immersion regimes showed appreciable softening of both restorative materials evaluated.