Effect of light curing modes of high-powered LEDs on temperature rise under primary teeth dentin (an in vitro study)

Abstract

Abstract 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 was 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 adapted 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 ± 0.2; 4.7 ± 0.4), whereas the lowest values were recorded with pulse mode under 1-mm-thick dentin (2.7 ± 0.1; 2.5 ± 0.2) during stage 1 curing and resin composite polymerization, respectively. Pulse mode produced significantly lower values than 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.