Abstract: A germicidal toothbrush that includes a head with perpendicularly aligned bristles made of an optical fiber capable of transmitting germicidal ultraviolet light. The toothbrush includes a main optical fiber that extends longitudinally inside the handle and terminates inside a brush head cavity. Perpendicularly aligned and attached to the brush head is a plurality of bristles. The distal end of the main optical fiber includes a sloped surface so that coherent ultraviolet light may be emitted at a critical angle so that it enters the ends of the bristles and then travels longitudinally therein to the surrounding teeth and gum surfaces. The ends of the bristles are coupled to a metal bar that connects to a connecting rod. The connecting rod is coupled to an internal electric motor that that causes the bristles to reciprocate back and forth on the head.