Purpose:This study measured the temperature increase induced by various types of
curing units during resin cement polymerization under ceramic restorations. Materials
and Methods: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.
Results: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 highintensity
halogen curing units. Conclusion: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. Int J Prosthodont 2004;17:200–204.