Changes in Irradiance and Polymerization Efficiency According to the Operating Cycle of Light-Curing Units

Abstract

Curing lights are indispensable devices in restorative dentistry, as they provide the necessary energy for resinous materials to achieve adequate mechanical, chemical, and physical properties. However, their performance depends not only on the irradiance reported by the manufacturer but also on the stability of the emission throughout usage cycles. Therefore, the objective of this study was to establish, based on current literature, how usage cycles modify the irradiance of curing lights and how this variation affects polymerization efficiency. The results showed that as the battery discharges or usage cycles accumulate, irradiance and dose decrease, leading to a reduction in the effective energy received by the restorative material and compromising the conversion rate, especially in wireless and low-cost lights. It is concluded that the stability of irradiance across cycles should be considered a critical factor for achieving adequate curing. Periodic monitoring of the lamps is a fundamental measure to preserve the quality and longevity of the restorations.