Effect of Battery Discharge on the Output from Budget Light-Curing Units

Objectives The manufacturers of budget light-curing units (LCUs) often claim to provide high-quality units that are equivalent to LCUs from major manufacturers. This study investigated the effects of battery discharge on the light output from different budget LCUs compared to a major manufacturer. Materials and Methods Two brands of budget LCUs (LY-A180 and LED-CL) were compared to a control LCU from a major manufacturer (3M). The LCUs were fully charged, and their light outputs were measured over one battery discharge cycle using repeated 10-second exposures at a 0-mm distance. Statistical Analysis Data were analyzed using one-way analysis of variance and Bonferroni post-hoc test. Results The budget LCUs delivered fluctuating light output values. In their first exposure, the budget LCUs delivered between 205 and 444 mW power, an irradiance between 533 and 1154 mW/cm2, and a radiant exposure between 5.3 and 11.5 J/cm2. As the number of exposures increased, their light output decreased between 24 and 81%, while the control LCU showed only a 4.9% decrease in power and irradiance. The light outputs from the budget LCUs were significantly less than the control LCU, and they were significantly from each other. Conclusion The budget LCUs tested could not maintain their power, irradiance, and radiant exposure output values as the battery discharged. This supports the recommendation that clinicians should be very cautious when using budget LCUs in their clinical practice.