High resolution charge-coupled device sensor vs. medium resolution photostimulable phosphor plate digital receptors for detection of root fractures in vitro.

Abstract

The aim of this study was to compare the diagnostic accuracy of a high resolution charge-coupled device (CCD) sensor and a medium resolution photostimulable phosphor (PSP) plate for detecting experimentally induced root fractures and further, to evaluate differences between images taken with various horizontal and vertical angles. Forty-seven extracted single-rooted human teeth mounted in a dry human skull were used in the experiment. The teeth were radiographed, before and after root fractures were induced, with two digital receptors: the Digora PSP system (approx. 8 lp mm(-1)) and the RVG-ui(TM), a CCD sensor with a high-resolution mode (15-20 lp mm(-1)). Four images were taken with each of the receptors of each tooth: one orthogonal exposure (O-images), one exposure with a vertical angle of 15 degrees by which the root was imaged elongated (L-images), and two eccentric exposures with a horizontal angle of 15 degrees mesially and distally. Three observers marked a fracture line if detected, in each image. Three sessions were held, one assessing the O-images, one the L-images, and one in which all four images of the same tooth were displayed simultaneously (X-images). The RVG-ui images obtained higher sensitivities than the Digora PSP images (P <0.05). Sensitivity was statistically significantly higher for the X-images than for both the O-images and the L-images (P <0.05). Based on the observed means, specificities were significantly different neither between the angles, nor between the images from the two digital systems taken with the same angle (P >0.05). It may be speculated that the difference in spatial resolution between the two digital systems accounts for the differences in their sensitivity.