CORRELATION BETWEEN DEPTH OF CURE AND TEMPERATURE RISE OF A LIGHT-ACTIVATED RESIN

The temperature rise, caused by 10 different curing units, in a prepol ymerized resin specimen was examined. For all units, the temperature i ncrease in a 60-s cycle followed a logarithmic curve, with the most ef fective light sources giving the highest temperature rise. In the surf ace layer the change of temperature ranged between 3.6 and 29.2-degree s-C, and 3.2 mm below the irradiated surface between 1.5 and 12.3-degr ees-C. The use of a 2-mm-thick isolating layer of glass ionomer result ed in a significant reduction in the temperature increase. The correla tion between the depth of cure and the temperature rise was of an expo nential or power nature; i.e., a small increase of the depth of cure w as followed by a disproportionately high increase in temperature.