Giomer restoratives, like other direct and indirect composites, are softened by foodsimulating liquids, especially citric acid and ethanol. They are also roughened by citric acid. SUMMARYThis study examined the effects of food-simulating liquid (FSL) on the hardness and roughness of giomer restoratives based on prereacted glass ionomer (PRG) technology. The materials investigated included a regular (Beautifil II [BT]) and a recently introduced injectable (Beautifil Flow Plus F00 [BF]) hybrid PRG composite. A direct hybrid composite (Filtek Z250 [ZT]) and an indirect hybrid composite (Ceramage [CM]) were used for comparison. The materials were placed into customized square molds (5 mm 3 5 mm 3 2.5 mm), covered with Mylar strips, and cured according to manufacturers' instructions. The materials were then conditioned in air (control), distilled water, 50% ethanol solution, and 0.02 N citric acid at 378C for seven days. Specimens (n=6) were then subjected to hardness testing (Knoop) and surface profilometry. Data were analyzed using one-way analysis of variance and post hoc Scheffe test (p,0.05). Mean Knoop hardness values for the control group (air) ranged from 53.4 6 3.4 (BF) to 89.5 6 5.2 (ZT), while mean surface roughness values values ranged from 0.014 6 0.002 (ZT) to 0.032 6 0.001 (BT). All materials were significantly softened by FSL. The degree of soften-