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Biomedical subjects

R G Stephens

Publications and source records attributed to R G Stephens.

34 records · Page 2Linked to original sources
PubMed1984

A clinical trial of a rare earth screen/film system in a periapical cassette.

In a clinical trial, a slow rare earth screen/film system (Siemens Titan 2D/Kodak XG) was used to obtain intraoral radiographs at conventional monitoring stages in endodontic treatment. The screen film image proved to be an effective substitute for the direct-exposure Ultraspeed periapical film. The intraoral cassettes, designed and fabricated for the study, were an adaptation of the flexible, vacuum-sealed cassettes used in mammography. It is believed that when a practicable periapical cassette is manufactured, many additional indications for the system are probable. Major reductions in patient exposure of at least 85% to 90% per periapical film would be effected.

Equipment Design↗
PubMed1982

An investigation of potential applications of intensifying screens in intraoral radiography.

In medicine, the somewhat degraded image from the screen/film system is accepted for most diagnostic purposes in the interest of radiation thrift. In dentistry, however, the superb image resolution and sharpness of the radiation-intensive, direct-exposure film is the standard for intraoral radiography. There may be occasions in dental practice where such quality is not necessary, thus making the high level of exposure difficult to justify. In a laboratory study, screen-type radiographs were effectively substituted for ultraspeed film in the monitoring stages of endodontic therapy and as posttreatment films in operative dentistry. Even with a slow system, the radiation exposure was one sixteenth of the usual periapical dose. If clinical trials support these conclusions, only the lack of a practical periapical cassette limits the application of this significant method of radiation reduction to dental practice.

Dental Restoration, Permanent↗
PubMed1975

Prevalence of recurrent herpes labialis and aphthous ulcers among young adults on six continents.

The prevalence of recurrent herpes labialis (RHL) and recurrent aphthous ulcers (RAU) in young adults - - 635 armed-forces recruits and 9897 health-profession students - - in 48 institutions in 21 countries was determined by a questionnaire survey. Two or more occurrences (lifetime prevalence) of RHL were reported by 33.2% of men and 28.0% of women; the corresponding figures for RAU were 38.7% and 49.7%. North American respondents, mainly from Canada, had a significantly higher prevalence of both lesions. There were some differences in relation to profession. Approximately 15% of all the people surveyed had had herpes labialis and 25% had had aphthous ulcers at least once during the previous year. Persons with a history of recurrence of one lesion were more likely to have a history of recurrence of the other.

Adolescent↗