Abstract: A recess is drilled into the buccal face of a tooth of a human subject, and a microdot having identifying information thereon is placed at the bottom of said recess whereafter the recess is filled with a transparent bonding material. When identification of the subject is desired, the microdot is photographed through the transparent filler material to provide a photographic print which contains the identifying information. The camera employed includes a fixture extending forwardly of the lens for accurately locating the camera lens relative to the microdot, the camera having a fixed focus lens whose focal length corresponds to the distance between the lens and the buccal face of the tooth plus the depth of the recess containing the microdot. A special technique, and an associated calibration instrument, are used for drilling the recess in the subject's tooth to a precise depth to assure that a sharp image of the microdot is obtained when the microdot is photographed by the fixed focus camera.