Abstract
To investigate the effects of irradiation time and immersion period on mechanical properties of photo-cured dental composite resins, static compression tests were made for specimens with different preparation conditions. For the dependence on irradiation time, specimens were produced for irradiation time of t=15, 20, 30, 60, 90, 120 and 150 seconds. When the irradiation time increases up to t=90 s, density, Young's modulus and brittleness of specimens increase. On the other hand, for the dependence on immersion period, specimens were immersed in ion exchanged water at 37±1 degree C for 0, 30, 60 and 90 days. Young's modulus increases until 30 days while fracture strain decreases because interface between fillers and resin becomes weak due to the absorption of water.
