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Optical power outputs, spectra and dental composite depths of cure, obtained with blue light emitting diode (LED) and
1University of Bristol, Dental School, Department of Oral and Dental Science, Biomedical Engineering and Biomaterials Science Section.
Objective:
To test the hypothesis that a prototype LED light curing unit, (LCU), a commercial LED LCU and a halogen LCU achieve similar cure depths, using two shades of a camphorquinone photoinitiated dental composite. To measure the LCUs' outputs and the frequency of the LED LCU's pulsed light, using a blue LED array as a photodetector.
Design:
Cure depth and light output characterisation to compare the LCUs.
Setting:
An in vitro laboratory study conducted in the UK.
Materials And Methods:
The LCUs cured A2 and A4 composite shades. A penetrometer measured the depth of cure. Analysis was by one-way ANOVA, two-way univariate ANOVA and Fisher's LSD test with a 95% confidence interval. A power meter and spectrograph characterised the LCUs' emissions. A blue LED array measured the pulsed light frequency from an LED LCU.
Results:
Statistically significant different LCU irradiances (119 mW/cm2 to 851 mW/cm2) and cure depths (3.90 mm SD +/- 0.08 to 6.68 mm SD +/- 0.07) were achieved. Composite shade affected cure depth. A blue LED array detected pulsed light at 12 Hz from the commercial LED LCU.
Conclusions:
The prototype LED LCU achieved a greater or equal depth of cure when compared with the commercial LCUs. LEDs may have a potential in dentistry for light detection as well as emission.
