Abstract: The tooth transilluminating light holder secures a lighting device to a tooth so that its light emitting end is perpendicular to the buccal (cheek) and lingual (tongue) surfaces of the tooth to be viewed. The tooth transilluminating light holder is supported at the tooth by a dental dam clamp to which it is affixed. Light provided to the surface of a tooth causes it to transilluminate, giving ample light within a drilled out tooth to accomplish endodontic (root canal) procedures. High intensity light is conducted along fiberoptic lines. These lines are inserted into the tooth transilluminating light holder and adjusted in and out to obtain proper proximity to the tooth's surface. This provides the desired transillumination within the tooth being viewed.