Spectral distribution of visible-light curing units – effect on the depth of cure in a dental composite resin

Twelve commercial visible-light (VL) curing units were examined in order to clarify the characteristics of intensity such as illuminating power and irradiance. The results showed that all VL curing units investigated had a peak in the wavelength range 460 to 500 nm. An equation proposed by us for the relation between the integral irradiance and the depth of cure indicated a good linearity (r=0.997) in the wavelength range between 460 and 480 nm when different VL curing units were used.