Assessing the effect of extraneous light on photoactivated resin composites

The authors investigated the effect of an operatory light and ambient fluorescent illumination on the curve values of three photoactivated resin composite materials. Infrared spectroscopy was used to evaluate the specimens after they were exposed to an operatory light at a distance of 30 inches for two, five or 10 minutes as well as after a blue-blocker shield was placed between the light source and the composite. The authors also measured cure values after exposing some specimens to 10 minutes of ambient ceiling fluorescent light only. Maximal cure values were determined by conventionally photocuring specimens. After 10 minutes' exposure to the operatory light, specimens were cured at a level from 70 to 80 percent of the maximal cure resulting from conventional light curing. The blue-blocker shield reduced curing to a level equivalent to that of a 10-minute exposure to ambient fluorescent lighting, which was nearly 0 percent.