The aim of this study was to evaluate different polymerization cycles on the hardness and surface gloss of acrylic resins for denture bases. Classico and Vip Cril Plus acrylic resins samples were made in dental stone molds. Powder-liquid ratio and resin manipulation were according to the manufacturers’ instructions, and the resulting mass pressed in metallic fl asks. The polymerization cycles were A - hot water bath at 74°C for 9 hours; B - hot water bath at 74°C for 8 hours + 100°C for 1 hour, and C - hot water bath at 74°C for 2 hours + 100°C for 1 hour. After polymerization, the samples were defl asked and submitted to finishing and polishing procedures, and stored in water at 37°C for 24 hours. A hardness indenter with load of 25 gf for 10 s evaluated the Knoop hardness values. A gloss meter evaluated the surface gloss using a light incidence of 60°. Data were submitted to ANOVA and Tukey’s test (α = 0.05). Hardness: There were signifi cant differences between resins regardless of polymerization cycles (Classico = 22.28 and Vip Cril Plus = 25.83). Significant differences occurred among polymerization cycles regardless of resins (A = 25.83, B = 24.64 and C = 21.73). There was similarity for the resin and cycle interaction (Classico: A = 24.51, B = 22.68 and C = 19.65; Vip Cril Plus: A = 27.15, B = 26.53 and C = 23.81). Surface gloss. Significant differences were shown between resins regardless of polymerization cycle (Classico = 57.26 and Vip Cril Plus = 49.38) and between polymerization cycles regardless of resin (A = 48.82, B = 53.46 and C = 57.68). Statistical diff erences were also found for the resin and cycle interaction (Classico: A = 52.32, B = 63.79 and C = 55.67; Vip Cril Plus: A = 45.32, B = 43.14 and C = 59.69). Diff erent polymerization cycles showed similar eff ects on hardness and different effects on the surface gloss of denture base acrylic resins
