Radiographic contrast. A comparative study of three dental X-ray films.

OBJECTIVE: To investigate the radiographic contrast of three dental X-ray films (Ultra-speed, Ektaspeed and Ektaspeed Plus, Eastman-Kodak, Rochester, NY, USA). METHODS: An aluminium stepwedge was radiographed for the objective assessment and a dried human mandibular segment including the teeth for the subjective evaluation. In the objective assessment, contrast was evaluated from the measured optic densities and the results analysed statistically by the Kruskal-Wallis one-way Anova and Mann-Whitney U test. Subjective evaluation was performed by 12 dentists with a range of clinical experience and scores were assigned to five dental and bony structures. RESULTS: In the objective evaluation there was no significant difference in contrast obtained with the Ultra-speed and Ektaspeed Plus films: both had significantly better contrast than Ektaspeed film. The subjective assessment revealed that the majority of the dentists preferred either Ultra-speed or Ektaspeed Plus films for contrast. CONCLUSION: Radiographic contrast of Ektaspeed Plus did not differ significantly from Ultra-speed and both were superior to Ektaspeed film.

Contamination of dental radiographic solutions.

Thirteen groups of periapical radiographic films were evaluated to determine and compare within and between groups the effects of contamination of the fixer solution with developing solution during radiographic processing. An aluminum penetrometer was used as the radiographic object to produce different optical densities. The images were compared using radiographic density and contrast as parameters. There were significant differences between the control groups and the groups processed with a contaminated fixer solution. No statistically significant differences were observed in the intragroup comparisons.

A method to evaluate and compare roentgenograms.

A simple and practical method is suggested to evaluate and compare roentgenograms concerning optical density and contrast. The method is specifically indicated for research in which a metallic stepwedge penetrometer and a photodensitometer are used. A PC computer may be optionally employed for the mathematical and statistical processing of the data.

[Radiopacity of composite resins]. / Radiopacidade de resinas compostas.

The author studied the radiopacity of six composite resins, submitted to radiographic examination in standardized conditions, only with kilovoltage variations. Along with resins it was radiographed an aluminium penetrometer, to compare their optical densities. The results showed that kilovoltagem variations interfered in optical densities of the resins, being more pronounced in 50-55, 55-60 and 60-65 kilovoltages. Despite this, the relations of optical densities as compared with that of penetrometer steps kept unaltered most fo the kilovoltages used.

[Influence of ambient storage temperature on radiographic density and contrast of dated and outdated film]. / Influência da temperatura ambiental de armazenagem sobre a densidade e o contraste radiográficos de filmes vencidos e não-vencidos.

The authors studied the influence of storage conditions of date and outdated films and the action of environment temperature over the same films. Four groups of films were studied: twenty-five outdated and twenty-five date films were under refrigeration; twenty-five date and twenty-five outdated films were under 36 degrees C temperature and 70% hygrometric for thirty days. Afterward, the films were exposed to radiation X at standardized conditions, together with an AI stepwedge penetrometer, to measure optical density; also the processing conditions were standardized. The results showed that temperature action and films date and outdated produced changes in the optical density and radiographic contrast.