Biomedical subjects
Publications and source records attributed to J E Seeliger.
Adenomatoid odontogenic tumours with a diameter of more than 4 cm are uncommon. Two cases, both measuring in excess of 7 cm, are described and the differential diagnosis discussed. The progressive growth and cortical perforation in these two cases support the view that it is a benign neoplasm rather than a hamartoma.
The aim of this study was to evaluate densitometrically four rapid processing solutions for dental films; also to identify those combinations of film, solution and temperature which produced the best results in terms of radiographic contrast and relative film speed at a given temperature. The film types used were Agfa Dentus M2, Flow X-ray and Kodak Ultra-speed while the rapid processing solutions tested were Kolchem Rapid Dev 1, Kolchem Rapid Dev 2, MEMS Ultra-Neg and Siemens Insta-Neg. An aluminium step-wedge was radiographed under standardized conditions. Processing was done manually at 18, 20, 22, 25, 27, 29 and 32 degrees C, the temperatures being controlled with the aid of two Julabo thermostatically controlled immersion circulators, to ensure constant temperatures. Unexposed films were processed at each temperature setting to determine base plus fog values. Densitometric readings were taken using a digital densitometer, and base plus fog values were subtracted from each reading. Radiographic contrast and relative film speed were calculated and the data obtained subjected to statistical analysis using Duncan's Multiple Range Test. It was concluded that Agfa Dentus M2 film processed with Kolchem Rapid Dev 2 at 18 degrees C gave the highest radiographic contrast of 0.44 and relative film speed of 4.36. All base plus fog values were within the acceptable limit of 0.25.
The aim of this study was to determine the effect of a stepwise rise in temperature on three film types processed in six different processing solutions and to identify the combinations of film, solution and temperature which produced the best results in terms of radiographic contrast and relative film speed. The film types were Agfa Dentus M2, Flow X-ray and Kodak Ultra Speed while the processing solutions were Agfa, Dürr, EBX, Kolchem, MEMS and Pro-tech. An aluminium step-wedge was exposed under standardised conditions. Processing was carried out in a Dürr 245L automatic processor with variable temperature settings from 25 degrees to 35 degrees C. Unexposed films were processed at each temperature setting to determine the base plus fog values. Densitometric readings were taken using a digital densitometer, and the base plug fog values subtracted from each reading. Radiographic contrast and relative film speed were calculated and the data obtained subjected to statistical analysis using Duncan's Multiple Range Test. It could be concluded that, as the processing solution temperature rose from 25 degrees C to 35 degrees C, both radiographic contrast and relative film speed increased. The highest radiographic contrast was obtained by Agfa film in Kolchem solution at 35 degrees C, while Kodak Ultra Speed film in MEMS solution at 35 degrees C gave the highest relative film speed. An acceptable base plus fog level of 0.25 was obtained in the case of Agfa film in combination with Agfa, Dürr and Pro-tech solutions and Flow X-ray film with Dürr solutions. All the other combinations produced a base plug fog level higher than 0.25.
In order to determine the effect of 7 dental film processing solutions on the quality of the radiographic image, an aluminium step-wedge phantom was exposed, using Agfa Dentus M2, speed group D, intra-oral x-ray films. The exposures were done under standardized conditions. Processing was carried out, using each of the 7 processing solutions, namely Agfa, Dürr, EBX, Kolchem, MEMS, Premier and Pro-tech strictly in accordance with the manufacturers' recommendations. After the processed films were subjected to densitometric evaluation, a step-wedge curve was drawn for each processing solution. The data pertaining to the radiographic contrast and relative speed values were calculated from the step-wedge curve and, together with the base plus fog values, were tabulated. Kolchem produced the highest radiographic contrast, followed closely by MEMS and Dürr. The relative film speed was almost identical for Kolchem, MEMS and Dürr. Regarding the base plus fog values, all 7 processing solutions were within the acceptable limit of 0.25.
The radiographic, or diagnostic, quality of the processed radiograph depends upon a number of factors, one of the most important being the characteristics of the film. The purpose of this study was to determine which of three intra-oral radiographic films, obtainable in this country, would give the best results in terms of density range, speed, contrast and base plus fog values. Agfa Dentus, Flow X-Ray and Kodak (all speed group D films) were exposed, using a calibrated G.E. 1000 x-ray generator at 65 kVp, 10 mA and 50 impulses (1 second) exposure time. The target-film-distance was 40 cm, the total filtration 2.0 mm Aluminium and the half-value layer 2.7 mm Aluminium equivalent. An aluminium step-wedge with 8 steps, in steps of 1.5 mm, and a natural premolar tooth, with a carious lesion, embedded in acrylic, were used as phantoms. An 8 mm-thick layer of base-plate wax and a 3 mm-thick lead plate were used to simulate tissue-scatter and prevent back-scatter, respectively. To determine the base plug fog value, an unexposed film from the same batch was processed simultaneously with each of the three films evaluated. All processing was done in a Dürr AC 245 L processor with automatic replenishment and a 6-minute cycle. The processing chemicals, viz., Kolchem High Stability X-ray developer and fixer, were mixed and used in strict accordance with the manufacturer's recommendations. The radiographic densities of each step of the step-wedge, and of carious and normal dentine of the phantom tooth, were determined by means of an RMI Digital Densitometer.(ABSTRACT TRUNCATED AT 250 WORDS)
In order to determine the effect of seven film processing solutions on the quality of the radiographic image produced on three intra-oral speed group D radiographic films, an aluminium step-wedge was used as a phantom and the films exposed under standardized conditions. Processing was carried out, using each of the seven processing solutions in strict accordance with the manufacturers' recommendations. The processed films were subsequently subjected to densitometric evaluation and the data pertaining to base plus fog, radiographic contrast, density and relative film speed, for each film-processing solution combination, were tabulated. The best combination proved to be that of Flow X-ray film and Kolchem processing solution.
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