Temperature rise within the pulp chamber during composite resin polymerisation using three different light sources.

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Polymer Chemistry

Background:

• Resin-based composites (RBCs) are widely used in dental restorations.
• Light-curing units (LCUs) are essential for polymerizing RBCs.
• Pulp temperature rise during polymerization is a clinical concern.

Purpose of the Study:

• To compare the temperature increase during resin-based composite (RBC) polymerization using two LED light curing units (LCUs) versus a halogen control light.
• To evaluate the thermal effects of different LCUs on dental pulp during polymerization.

Main Methods:

• Forty-five extracted molars (ages 11-18) were used with thermocouples placed in the pulp chamber.
• Teeth were maintained at 37°C +/- 1°C in a water bath.
• Three groups were tested: Halogen LCU (500 mW/cm²), Bluephase LED LCU (1100 mW/cm²), and Elipar Freelight2 LED LCU (1000 mW/cm²).

Main Results:

• Significantly higher temperature rises were observed during bonding agent curing compared to RBC curing across all groups.
• Both LED LCUs produced higher temperatures during polymerization than the halogen control.
• No significant difference in temperature rise was found between the two LED LCUs.

Conclusions:

• High-energy output LCUs pose an increased risk of pulpal injury during RBC polymerization compared to lower-energy sources.
• Clinicians should be aware of the potential for thermal trauma when using high-intensity light sources, especially when curing bonding agents.
• Despite higher temperatures, the mean rise with all tested units remained below the threshold for permanent pulp damage.