What is the Impact of Light Curing Modes of High-Powered LED on Temperature rise in Primary Teeth Dentin: An In Vitro Study

Abstract

Background: Temperature rise in the pulp chamber is a severe stress that can cause irreversible damage to the pulp. The objective of this study was to compare the temperature rise under primary tooth dentin induced by a light emitting diode (LED) with different light curing modes.Methods: Sixty dentin discs of 0.5- 1- 1.5- and 2-mm thicknesses were prepared from human primary molars. The resin composite placed in a Teflon cavity was cured using a high-powered LED (Foshan JERRY Medical Apparatus CO., LTD, Foshan, China) for 20 s. The different modes tested in this study were standard mode, ramp mode, and pulse mode (n=5). Temperature was recorded using a k-type thermocouple in direct contact with the dentin disc. Temperature change data were subjected to analysis of variance (ANOVA) and Tukey's test.Results: The highest temperature rise was observed under a 0.5 mm thick dentin disc with standard mode (4.7 ± 0.42), whereas the lowest values were recorded with pulse mode under 2 mm thick dentin (2.5 ± 0.23). Pulse mode produced a significantly lower temperature rise than standard mode for all dentin thicknesses (P < 0.05). Ramp mode gave significantly lower values than standard mode in the 0.5 mm group (P < 0.05). For the standard and ramp modes, the 0.5 mm thick group exhibited a higher temperature rise than the 2 mm thick group (P < 0.05).Conclusions: Temperature rise related to dentin thickness and curing modes. The standard mode led to a significantly higher temperature rise under thinner dentin than the other modes. Pulse mode gave the lowest values. Thus, it is recommended for use in deep cavities. Clinical Significance: The temperature rise during polymerization of the resin composite with the high-powered LED appeared to be below 5.5 ℃. Hence, it appears to be safe for use in pediatric dentistry.