L.R. Manson-Hing

A comparison of panoramic and intraoral radiographic surveys in evaluating a dental clinic population

Abstract The effectiveness of radiographic surveys in detecting basic radiographic signs for the initial examination of patients in a specific dental clinic population was investigated. A sample of 300 patients showed that panoramic periapical and bitewing radiographs are all needed for a complete radiographic evaluation. Panoramic plus bitewings and periapical plus bitewings were the next most effective surveys with either survey being less effective than the other for some radiographic signs.

Cariogenicity of Nine Sugars Tested with an Intraoral Device in Man

Nine sugars and sugar alcohols were assessed for their effect on experimental caries with an Intraoral Cariogenicity Test (ICT). Sample bovine enamel surfaces were submitted to simulated cariogenic co

Enhancement of Fluoride Effectiveness by Experimental Cariogenic Priming of Human Enamel

An intraoral cariogenicity test (ICT) was used to study the enhancement of fluoride treatments (2% NaF or 8% SnF2) that resulted from prior cariogenic challenge to human enamel surfaces. Measurements of enamel microhardness and microradiography indicated higher resistance to the cariogenically primed than for the unprimed surfaces. These results are interpreted as an adaptation of enamel to a challenging local environment by the formation of highly caries resistant minerals in the microspaces created by the priming challenge. With this adaptive reaction, tooth surfaces at risk were converted to surfaces of higher resistance than nonprimed surfaces. It is suggested that the concept of enamel adaptation to the cariogenic challenge can be applied clinically to arrest incipient caries, especially in patients who respond well to preventive disciplines that include the use of fluoride treatments.

A study of the focal troughs of three panoramic dental x-ray machines: Part I. The area of sharpness

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 study of the focal troughs of three panoramic dental x-ray machines

Abstract A comparison of three panoramic x-ray machines revealed little difference in vertical and horizontal magnifications between machines; larger differences were seen to exist between vertical and horizontal magnifications on each machine.

Relations between tooth positions and focal troughs of panoramic machines

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 midline-incisal point as a reference point, various composite drawings of tooth positions of patients were made. The total composite of all teeth revealed the striking similarity of the arches. Superimposition on the focal troughs showed that the focal trough of the Panorex easily encompassed all tooth positions. The focal trough of the Orthopantomograph encompassed all tooth positions, although tooth centers lie on the edges of the trough. The focal trough of the GE-3000 with profile index 10 extended so far buccally that many teeth are positioned lingual to the trough. The focal trough of the GE-3000, when reduced uniformly to profile index 7.5, encompasses all tooth positions although some positions fall quite near the borders of the trough.

Radiation exposure and distribution measurements for three panoramic x-ray machines

1. Exposures to internal sites in the phantom varied as follows: Panorex, 0.3 mr to 2.4 r; Orthopantomography, 0.4 mr to 0.8 r; Panelipse, 0.2 mr to 1.4 r. 2. With the phantom exposed for a normal-density radiograph at 65 KVP, the average radiation exposure at the sites measured were for the Panorex, Orthopantomograph, and Panelipse respectively: 8, 13, and 4 mr at the pituitary gland; 22, 62, and 8 mr at the superior area of the parotid gland; 13, 8, and 5 mr at the thyroid gland; 343, 425, and 365 mr at the submaxillary gland; and 50, 154, and 272 mr at the base of the tongue. 3. External exposures to the phantom and patients were found to be in good agreement at the low KVP. At the high KVP (using patients who were larger than the phantom), exposures at lateral and posterior sites showed relatively good agreement between phantom and patients, while exposures at anterior sites were less in patients. 4. The average stray radiation measurement at 1 meter from the phantom during pantomography with the three machines was 0.125 mr per exposure cycle. Individual averages were: Panorex, 0.10 mr; Orthopantomograph, 0.13 mr; and Panelipse, 0.15 mr.

A comparison of combinations of clinical and radiographic examinations in evaluation of a dental clinic population

Panoramic periapical anterior and posterior bitewing radiographic, mirror-explorer, and transillumination clinical examinations were performed on 300 patients. Various combinations of the radiographic and clinical examination techniques were compared in terms of their ability to diagnose caries, alveolar bone loss, calculus, periapical bone lesions, impacted teeth, root tips, and miscellaneous conditions. A mirror-explorer clinical examination with panoramic and posterior bitewing radiographs and either anterior bitewing radiographs or transillumination proved to be as efficient in the initial examination of patients as the mirror-explorer clinical examination with periapical and posterior bitewing radiographs.

Microdensitometric and visual evaluation of the resolution of dental films

Abstract The resolution of intraoral dental films and some screen-film combinations are measured with two methods.

The accuracy of an x-ray film quality-assurance step-wedge test

The accuracy of an aluminum step-wedge quality-assurance test for machine and processor in dental radiography was determined. The clinical radiographic density range accepted by twenty dentists was similar to eight steps of an aluminum step-wedge test object, with dentists using six or seven steps. The test used a two-step density shift to detect and separate changes in both x-ray machine and film processing before radiographic quality becomes clinically unacceptable. Measured latent image fading of test films stored for months was small and did not affect the test performance. The accuracy of the step-wedge test in detecting eighteen machine and film-processing variables was measured with a densitometer. Possible comparisons with measurements made by an accepted densitometric method used in medical radiography showed similar results. The test can be used in lieu of more costly, time-consuming tests.