Performance of Standalone Dental Radiometers for Light Output Check

Objective:

Optimal polymerization of dental materials depends on several factors among which light output of the curing unit. Aim of this study is to compare the irradiance of 6 curing lights (Paradigm™ LED Curing Light-3M ESPE, Demi^Plus-Kerr, SmartLite® Max-Dentsply, bluephase®-Ivoclar Vivadent, VALO cordless-Ultradent, Radii Plus-SDI) measured with 3 commercial dental radiometers (LED Radiometer-Kerr, LED Radiometer-SDI, bluephase meter-Ivoclar Vivadent) with the irradiance declared by the manufacturer.

Method:

The light output of mentioned devices was measured 5 times (n=5) with each of the three radiometers. The offset between the recorded mean values and the irradiance values stated by the light manufacturers was calculated (given in %). Data collected was statistically analyzed using one-way ANOVA (p≤0.05).

Result:

The following irradiance values were measured

Device	Claimed Irradiance*  [mW/cm²]	LED Radiometer-Kerr		LED Radiometer-SDI		bluephase Meter-Ivoclar Vivadent
		Measured irradiance[mW/cm²]	Offset(%)	Measured irradiance [mW/cm²]	Offset(%)	Measured irradiance [mW/cm²]	Offset(%)
Paradigm	1200	700±0.00	-41.67±0.00	1379±17.10	14.92±1.43	1230±15.81	2.50±1.32
DemiPlus	1100	700±27.39	-33.64±2.49	1642±91.83	49.27±8.35	1936±72.32	76.00±6.57
SmartLite max	1200	320±27.39	-73.33±2.28	434±24.85	-63.83±2.07	954±11.40	-20.50±0.95
Bluephase	1200	700±0.00	-41.67±0.00	1001±17.10	-16.58±1.43	1504±19.49	25.33±1.62
VALO cordless	1400	570±27.39	-59.29±1.96	1099±48.40	-21.50±3.46	1108±83.19	-20.86±5.94
Radii Plus	1500	530±27.39	-64.67±1.83	1920±0.00	28.00±0.00	470±52.44	-68.67±3.50

 There was important variability of irradiance measurements between different radiometers. Kerr radiometer showed significantly lower irradiance values than the values registered by the other radiometers and those stated by the manufacturers. Radii Plus and Demi^Plus were the devices with the highest variability. Differences between claimed and measured irradiance were significant for all tested devices, except for Paradigm when tested with the bluephase meter.

Conclusion:

All curing lights tested showed high variability in irradiance readings. There was no positive intra-brand correlation curing light-radiometer. For curing light performance check standalone radiometers are not reliable. therefore other testing methods should be considered (e.g. resin curing tests).