Flexural strength and Hounsfield impact resistance of a denture base material were yearly tested in a time scale of 5 years. Impact energy for fracture was continuously stable during the 5-year-long storage in water. Forces caused fracture in wet circumstances were between 60-80 N during the observation period. A significantly (p < 0.001) higher forces were measured at fractures for dry specimens in comparison to the wet polymer material in some years.