Rare earth screens for panoramic radiography.

Six panoramic radiographs, each made with a different screen/film combination, were compared for "periapical visibility" by fourteen dentists. Two combinations (a par-speed and a high-speed) used calcium tungstate screens, and three used rare earth screen systems four times faster than par-speed. One other combination consisted of a single rare earth screen plus a single-coated detail film. The radiographs produced by the faster rare earth screen/film combinations were found to be similar in quality to those produced by calcium tungstate screens. Rare earth screens could be used for panoramic radiography while maintaining quality and reducing exposure.