Effect of Light Curing Modes of High-Powered LEDs on Temperature Rise under Primary Teeth Dentin (An In Vitro Study)

Background: Temperature rise in the pulp chamber is a severe stress that can cause irreversible damage to the pulp. This study aimed to evaluate the effect of three curing modes of a high-powered LED and two remining dentin thicknesses on the temperature rise under primary teeth dentin. Methods: One dentin disc of 1 mm thickness were prepared from human primary molar. The dentin disc was exposed to curing light using a high-powered LED for 10 s to simulate bonding agent polymerization (stage 1 curing). Five specimens of resin composite were cured for 20 s. The different modes tested were standard, ramp, and pulse mode (n=5). After that the dentin disc was grinded to 0.5 mm thick and the experiments were repeated. Temperature change data were subjected to analysis of variance (ANOVA) and Tukey's test. Results: The highest temperature rise was observed under the 0.5-mm-thick dentin disc with standard mode (7.6±0.234; 4.78±0.4207), whereas the lowest values were recorded with pulse mode under 1-mm-thick dentin (4.8±0.458; 3.16±0.829) during stage 1 curing and resin composite polymerization, respectively. Pulse mode produced a significantly lower values compared to standard mode in all conditions (P<0.05). An inverse proportion was found between the mean temperature rise values and the dentin thickness. Conclusions: High-powered LEDs should not be used to cure bonding agents in deep cavities. The maximum temperature rise induced by a high-powered LED during resin composite polymerization was not critical for pulpal health. Temperature rise related to dentin thickness and curing modes.