Temperature increase during resin cement polymerization under a ceramic restoration: effect of type of curing unit

This study measured the temperature increase induced by various types of curing units during resin cement polymerization under ceramic restorations.

The resin cement was polymerized between a ceramic specimen (diameter 5 mm, height 2 mm) and a dentin disk (diameter 5 mm, height 1 mm) with a conventional halogen light, a high-intensity halogen light, a plasma-arc light, and a light-emitting diode unit. The temperature increase was measured under the dentin disk with a J-type thermocouple wire connected to a data logger. Ten measurements were carried out for each curing unit. Difference between starting and highest temperature readings was measured, and the 10 calculated temperature changes were averaged.

Temperature increase varied significantly depending on curing unit used. The plasma-arc light induced significantly higher temperature increases than any other curing unit. The light-emitting diode unit produced the lowest temperature changes. There were no statistically significant differences between the conventional and high-intensity halogen curing units.

Polymerization with curing units characterized by high energy output (plasma-arc light) caused higher temperature changes compared to other curing units, but the temperature increase detected was not viewed as critical for pulpal health.