title: A study of the focal troughs of three panoramic dental x-ray machines. Part I. The area of sharpness.
abstract: A comparison of three panoramic x-ray machines revealed that the focal trough of the panorex curved inward in the posterior region, that of the GE-3000 remained straight, and that of the Orthopantomograph flared outward. The panorex was found to have the widest trough in the anterior region; the GE-3000 had the widest trough in the posterior regions.
mesh_terms: D003748:Dental Equipment / Q000592:standards*; D008953:Models, Anatomic; D011856:Radiographic Image Enhancement / Q000592:standards; D011858:Radiographic Magnification / Q000592:standards; D011861:Radiography, Dental / Q000295:instrumentation / Q000592:standards*; D011862:Radiography, Panoramic / Q000295:instrumentation / Q000592:standards*