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Dental composite depth of cure with halogen and blue light emitting diode technology
R W Mills1, K D Jandt, S H Ashworth
1Department of Oral and Dental Science, University of Bristol.
Objectives:
To test the hypothesis that a blue light emitting diode (LED) light curing unit (LCU) can produce an equal dental composite depth of cure to a halogen LCU adjusted to give an irradiance of 300 mWcm-2 and to characterise the LCU's light outputs.
Materials And Methods:
Depth of cure for three popular composites was determined using a penetrometer. The Student's t test was used to analyse the depth of cure results. A power meter and a spectrometer measured the light output.
Results:
The spectral distribution of the LCUs differed strongly. The irradiance for the LED and halogen LCUs were 290 mWcm-2 and 455 mWcm-2, when calculated from the scientific power meter measurements. The LED LCU cured all three dental composites to a significantly greater (P < 0.05) depth than the halogen LCU.
Conclusions:
An LED LCU with an irradiance 64% of a halogen LCU achieved a significantly greater depth of cure. The LCU's spectral distribution of emitted light should be considered in addition to irradiance as a performance indicator. LED LCUs may have a potential for use in dental practice because their performance does not significantly reduce with time as do conventional halogen LCUs.