Light Output from 37 Curing Lights Monitored for One Year

Objectives: This study re-evaluated the light output from 37 Bluephase Style (Ivoclar Vivadent) curing lights after 1 year of use by students.
Methods: 37 Bluephase Stylelight emitting diode curing lights were purchased. Upon receipt, the spectral radiant power from each curing light was independently and blindly measured using a 6-inch integrating sphere (Labsphere) attached to a fiberoptic spectroradiometer (Ocean Optics). The lights were also measured with the Bluephase Meter II, the LED Radiometer (Kerr), the SDI Radiometer (SDI), and the checkMARC (BlueLight Analytics). The curing lights were remeasured one year later using the same equipment. In the intervening period, the curing lights had been used by students. The results were analyzed by one-way ANOVA and Tukey post-hoc test (a=0.05).
Results: None of the Bluephase Style curing lights required maintenance. The emission spectra from the lights were almost identical and remained unchanged. The mean irradiance values from the 37 Bluephase Style lights were not significantly different at baseline (1274 mW/cm²) and after one year (1299 mW/cm²), a 1.9% difference. When using a tip diameter of 9 mm, the Bluephase Meter II results (1329 mW/cm²) were not significantly different from the integrating sphere measurements. When using a tip diameter of 10 mm, the checkMARC results (1321 mW/cm²) were not significantly different from the integrating sphere measurements (1299 mW/cm²). The SDI Radiometer (1206 mW/cm²) and the LED Radiometer measurements (943 mW/cm²) were both significantly lower. The mean power measurements from the Bluephase Meter II (811 mW) were also not significantly different from the integrating sphere (808 mW) measurements.
Conclusions: The light output from the 37 Bluephase Style curing lights was not significantly different at baseline and after one year of student use. The Bluephase Meter II and the checkMARC reported irradiance values that were the same as those obtained using the integrating sphere, but required different tip diameters to be entered into the devices.