The influence of storage conditions on film characteristics of Ektaspeed plus and Ultra-speed films.

BACKGROUND

Dental professionals were reluctant to accept Ektaspeed (Eastman Kodak Co.) intraoral film despite its X-radiation dose-sparing advantages for patients. One reason may have been Ektaspeed film's known sensitivity to long-term storage as compared with that of Ultra-speed film (Eastman Kodak Co.). In 1995, Kodak replaced Ektaspeed with Ektaspeed Plus, claiming it had better resolution and higher stability than Ektaspeed, as well as equal exposure radiation. The authors compared film response to storage condition and time for Ultra-speed and Ektaspeed Plus films.

METHODS

The authors stored 10 boxes of newly produced Ultra-speed and Ektaspeed Plus film in five locations. They conducted 23 image trials over a 26-month period, exposing each film with an aluminum step-wedge under controlled conditions. After processing the film, they measured density to calculate the film's base + fog and contrast index values.

RESULTS

The authors found significant differences in film type (P = .0002), processing status (P < .0001), storage location (P < .0001) and month of storage (P < .0001). They also found a film-type-by-location interaction (P < .0001) but did not find a film-type-by-processing interaction (P = .3271). Regression lines suggested that the optical density of base + fog levels rose more steeply for Ultra-speed film than they did for Ektaspeed Plus film. A significant association of decreasing contrast with increasing months of storage was seen with Ultra-speed film (P < .0001). There was a small increase in base + fog levels resulting from the use of used solutions over the course of the study.

CONCLUSIONS

Ektaspeed Plus film compared favorably with Ultra-speed film under all conditions.

CLINICAL IMPLICATIONS

The authors recommend the use of Ektaspeed Plus film for intraoral imaging, as its performance is comparable to that of Ultra-speed film while requiring half the X-radiation exposure to patients. Clinicians must ensure that the correct safelights and processing solutions are used before switching to the new film.