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.
A resolution test pattern was used to determine the size, position, and centers of the focal troughs of four panoramic x-ray machines. The focal troughs were located at slightly different positions for each machine. The center of each focal trough produced varying degrees of sharpness. The average widths of the focal troughs were not greatly different… (More)
Sharpness zones of the Orthopantomograph-5, Autopan, and Panorex were delineated with the use of a standard multiline test object at 1.7 line pairs per millimeter. In addition, Panorex zones made with medium- and high-speed screens were compared. The focal troughs of all machines covered most tooth positions. The Autopan and Orthopantomograph troughs were… (More)
A comparison of the established focal troughs of three panoramic machines with positions of the teeth in the dental arches of 240 patients. The patients, divided into twelve cells, were selected on the basis of race, sex, age, number of teeth, and occlusion. Occlusal registrations were made in fast-set acrylic. Tooth centers were identified and, with the… (More)
1. Tooth positions did not vary between ages and sexes in Japanese. 2. As the arches lengthened posteriorly, anterior tooth positions showed little variation. 3. Japanese tooth positions lie within the range shown for Caucasoid and Negroid persons. 4. Japanese tooth positions have a shorter anteroposterior dimension than their Caucasoid and Negroid… (More)