Abstract: A teeth whitening device having a lens which fits against the teeth. The lens has a casing containing a plurality of light emitting diodes which project light into the lens. The lens filters the light to produce a 430 to 450 nanometer blue light which is projected onto the surface of the teeth. When carbamide peroxide is placed on the surface of the teeth the blue light will activate the peroxide to whiten the teeth several shades within one hour without heating or sensitizing the teeth. The lens has a bite plate which a user bites down on to keep the lens in position against the teeth, leaving the user's hands free. The device and method are safe enough for use outside the dental office.