RANGE OF EXPOSURE TIME AND IMAGE QUALITY IN CONVENTIONAL AND DIGITAL RADIOGRAPHS: AN IN VITRO STUDY.

The purpose of this study was to determine the range of exposure time to obtain acceptable bitewing radiographic images using conventional (InSight, Kodak) and digital (DenOptix™, Gendex) systems. Thirty sound molars were radiographed by bitewing technique at exposure times ranging from 0.06s to 2.50s. Five dental radiologists evaluated the resulting 340 radiographs, classifying them as (1) unacceptable, (2) acceptable and (3) of good quality. Frequencies were analyzed by Kruskal-Wallis and Wilcoxon tests, and inter-examiner agreement was determined by Cohen's kappa statistics. Radiographs of good diagnostic quality in conventional system were obtained with exposure times ranging from 0.10s to 1.00s while in digital system the time ranged from 0.06s to 1.60s (P<0.05). It was also observed that 75.3% of the digital images and 47.1% of the conventional images were considered of good quality. The digital system with phosphor plates (DenOptix™) produces acceptable interproximal radiographic images in a wider range of exposure time than the conventional system (InSight film). [ABSTRACT FROM AUTHOR]