Properties of seven newer resins polymerized using a water bath, microwave energy, or by visible light were measured. Generally, the new resins were harder and less flexible but had lower impact strength than did the heat-polymerized, rubber-modified resin (Lucitone). The light-activated urethane dimethacrylate resin (Triad) was the least flexible. Microwave polymerization improved the modulus of elasticity of two resins, decreased the impact strength of one, and had little effect on the properties of two other resins.