A study of temperature rise in the pulp chamber during composite polymerization with different light-curing units

The study compared pulp temperature rise during polymerization of resin-based composites (RBCs) using halogen and LED light-curing units (LCUs).

A total of 32 teeth extracted from patients aged 11-18 years were used in the study. Thermocouples placed on the roof of the pulp chamber using a novel 'split-tooth' method. In Group 1 a halogen LCU with a light intensity of 450 mW cm(-2) was used and in Group 2, an LED LCU with a light intensity of 1100 mW cm(-2) was used. The teeth were placed in a water bath with the temperature regulated until both the pulp temperature and the ambient temperature were stable at 37 degrees C. Continuous temperature records were made via a data logger and computer. The increase in temperature from baseline to maximum was calculated for each specimen during the curing of both the bonding agent and the RBC.

The rise in pulp temperature was significantly higher with the LED LCU than with the halogen LCU for bonding and RBC curing (p<0.05). The major rise in temperature occurred during the curing of the bonding agent. During the curing of the RBC, rises were smaller.

Curing of bonding agents should be done with low intensity light and high intensity used only for curing RBC regardless of whether LED or halogen LCUs are used.