Experimental curing unit: Influence of the lighting modes on the dental pulp chamber temperature

High irradiance of a curing unit with continuous lighting is associated with high output temperature that could lead to high pulp chamber temperature. The pulse-lighting mode has been studied as an alternative to the continuous lighting. The aim of our study was to analyze the influence of the lighting modes of the light curing unit on the dental pulp chamber temperature of extracted teeth. We constructed an experimental unit, with different irradiances with light exposure times of 10 and 20 sec; the output temperature and irradiances were measured. The irradiances were used to polymerize resin composites restored in teeth with different light exposure times. Then, the temperature of the dental pulp chamber were determined, whereas, the temperature of the dental pulp without light exposure was used as baseline. A commercially available curing unit that was checked to have continuous-lighting mode with an irradiance of 900 mW/cm2 and is operated only in 20 sec was employed for comparison with the pulsed lighting mode curing unit. We found that the output light and pulp-chamber temperatures of the pulse-lighting curing unit were significantly lower than those observed for a continuous-lighting curing unit. With respect to the pulsed-lighting curing unit, the output-light temperatures associated with the irradiance levels of 900 in 20 sec and 1,000 mW/cm2 in 10 or 20 sec showed significant differences. The pulp-chamber temperature decreased during resin composite polymerization but was still slightly higher than the baseline. When used in vivo, the slight value added to the normal dental pulp chamber temperature value could be higher than the normal temperature of the pulp chamber which could cause problems in dental pulp chamber.