Abstract: A dental film-based radiograph which is relatively small of the order of 40 mm by 30 mm is scanned and converted to a digital image by mounting the radiograph on a table movable in a single direction at a transparent aperture of the table and by transmitting through the radiograph a beam of laser light from a line source with the line parallel to the radiograph and defining a collimated beam of parallel light at right angles to the line and lying in a single plane containing the line. A detector in the form of a linear array of CCD detector elements is arranged in the plane to receive the light passing through the radiograph. The whole is contained in an enclosure to exclude ambient light. The scanning movement can be effected step by step or continuously with the laser source pulsed.

Abstract: A three-dimensional model of the teeth of a patient is prepared by taking molded impressions of the mandibular and maxillar teeth, placing separately the impressions on a support table define an X-Y plane and detecting the Z distance from a probe by directing a beam of laser light onto the impression and calculating from the pattern of reflected light a centre of the light falling on an area array. The scanning in the X-Y plane is effected continuously and is limited by datum points defining a dental arch. The impression is then tilted and the process repeated and information correlated to provide the three-dimensional model. A partial impression is then taken of both mandibular and maxillar teeth in comparison with datum points to provide information concerning the bite (occlusal) positions of the teeth. This information is then compared with the full impression to simulate using the three-dimensional models movement of the jaw from an open position to the bite (occlusal) position.