Effect of wavelength and radiant emittance on light transmittance and temperature increase in dental resin-based...

To evaluate the effect of wavelength and radiant emittance on light transmittance and heat generation through dental resin-based composites.

Light-emitting diodes on the blue, green, and red wavelength spectra were assembled and characterized using a spectrometer (MARC Resin Calibrator, BlueLight Analytics). Voltage (V) and amperage (A) from each LED was set up to emit a 500-, 1000-, 2000-, 3000-, or 4000-mW/cm2 radiant emittance. A self-cured resin-based composite model was fabricated in two pastes, one with benzoyl peroxide and another with ethyl 4-dimethylaminobenzoate. The two pastes were mixed and placed into a mold (ø=10 mm, 2 mm thick) until completely hardened. A power analysis was conducted to determine the sample size to provide a power of at least 0.8 and α=0.05. Light transmittance through the 2-mm thick composite-based sample was evaluated using a spectrometer (n=10). Heat generation (oC) in the resin-based composite sample induced by the exposure to the tested wavelength spectra and radiant emittances were recorded using an infrared camera (FLIR ONE PRO, FLIR Systems) (n=10). Statistical analyses were performed using analysis of variance and the Tukey's test for multiple comparisons.

Light transmission systematically increased based on radiant and wavelength emittances (p<0.0001). Heat generation was directly proportional to radiant emittance but indirectly proportional to wavelength emittance (p<.0.0001).

Despite its limitations, this study found that increasing wavelength emittance seems to configure a great alternative to increase light transmittance through resin-based composite restorations while reducing heat generation.