Observer differentiation of mechanical defects versus natural dental caries cavitations on monitor-displayed images with imaging plate readout

Abstract

Objective. The purpose of this study was to compare the ability of dentists to detect mechanically created defects vs natural dental caries cavitations on the proximal surfaces of extracted teeth by means of storage phosphor imaging plate technology. Study design. Fifty-two extracted molar and premolar teeth were blocked into sets for bitewing radiographs through use of the DIGORA digital imaging system. Sixteen natural caries cavities and 28 artificial lesions were present in the 80 proximal surfaces included in the study. A group of 16 dentists assessed proximal lesions on unenhanced images on the monitor and 1 month later on contrast-enhanced images. A different group of 16 dentists assessed proximal lesions on contrast-enhanced images and 1 month later on unenhanced images. The Mann-Whitney U test was used to check for a reading-order effect. The Zelen test of odds ratio was used to test for homogeneity, and the Mantel-Haenszel analysis or stratified logistic regression was used for inference about the common odds ratio. Alpha was set at P < .05. Results and Conclusions. With the DIGORA system, there was little difference between the detection rates of mechanical defects and natural carious cavities with unenhanced images, but the mechanical defects were more readily detected when contrast-enhanced images were used. Cavity depth positively affected the odds of diagnosis of lesions, with deeper lesions being more readily detected than more superficial ones irrespective of whether they were natural or artificial. In comparison with findings of previous studies in which film and a charge-coupled device detector were used, the overall detection rate for natural dental caries was remarkably constant across the modalities.