To evaluate light transmission of IPS Empress, spectral transmittance using transmitted light and luminous transmittance were determiend. The results were as follows:
1. In luminous transmittance, light was transmitted more in the order of T 1, O 2, TC 2, and A 2. Luminous transmittance decreased as the thickness of all ingots increased.
2. In spectal transmittance of all thicknesses and wavelengths light was transmitted more in the order of T 1, O 2, TC 2, and A 2.
3. In spectral transmittance of each wavelength, decrease of transmittance in short wavelength was great for all ingots. Transluscent ingot with dentin color (TC 2) and dentin color ingot (A 2) were greater than others.
