Abstract
Aim: To evaluate the thermal emission by three types of light sources units. Materials and methods: Temperature were recorded from distance of 1mm from a thermocouple the tip of three different types of light sources units including one Blue cap (LED) source unit, one special tungsten halogen (S2) source unit, and one invisible technology (IV_ Tech) source unit. Temperature changes were recorded in 10 second intervals up to 40 seconds (10, 20, 30, and 40 seconds). Temperature measurements were repeated three times for every light source unit after a one hour standby period. Mean values were compared statistically with Chi-Square test to determine the significant difference among the tested groups at (p<0.05) level of significance. Results: The highest temperature rises (39.6ºC) occurred dur-ing activation of an IV_ Tech light source unit for every test period. The least temperature increase (24 ºC) occurred with a LED light source unit for each tested period. Conclusions: These results indicated that the choice of light activation unit and curing time is important during the light activated polymeri-zation of composite resins to avoid any thermal damage to the pulp
