Long-term quality management of third-generation LED light-curing units: A 10-year retrospective analysis

The radiant exposure of light-curing units (LCU) is the most important parameter in resin-based composite polymerization. Ensuring the quality management of light-curing procedures in dental offices is thus vital. Therefore, this report retrospectively evaluated the performance, frequency, and reasons for service removal of all third-generation LED light-curing units used in one healthcare center over 10 years. The tip irradiance of LCUs (Bluephase G2, Ivoclar Vivadent) was monitored with a dental radiometer (Bluephase Meter, Ivoclar Vivadent) at 1-2-month intervals, regardless of the duration of use. Additional measurements were conducted after special incidents (e.g., accidental dropping). Measurements were documented in the dental practice management software. The date and reasons for additional measurements or removal were also recorded. In two-thirds of incidents, the LCU was accidentally dropped, and in approximately half of these cases, the LCU had to be replaced. The mean of all 554 irradiance measurements over 10 years was (1,375 ± 68) mW/cm2, higher than the value specified by the LCU manufacturer. Even for LCUs with data available for the entire 10 years, no relevant loss of tip irradiance was detected. While this study was the first to demonstrate such performance stability of third-generation LED LCUs over 10 years, it should not lead to the complete abandonment of routine quality assurance procedures for this type of device due to unreported or unrecognized accidents.