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The purpose of this report was to respond to aspects of the RTI/UNC systematic review relating to the radiographic diagnosis of dental caries. The systematic review was commissioned as part of the NIH Consensus Development Conference on Diagnosis and Management of Dental Caries Throughout Life. The systematic review evaluated the dental literature from 1966 to 1999. Well-defined search criteria along with clear inclusion and exclusion criteria were used to perform the review. Some of the inclusion and exclusion criteria used in the systematic review may have limited the evidence supporting the use of radiography, especially for the diagnosis of proximal surface caries. The RTI/UNC review only included studies in which sensitivity and specificity were reported or could be derived from the data presented. Studies that used the receiver operating characteristic as a measure of diagnostic accuracy were not included. Although the strength of evidence is considered poor, this does not mean that the use of radiographic methods is of no diagnostic value. It simply means that, using the criteria established by the systematic review, the evidence is inadequate to validate the method. Guidelines should be developed for assessing diagnostic methods that assist researchers in developing study designs that will hold up to critical review.

Previous studies have shown that occlusal dental caries can be arrested with sealants. Radiographic monitoring must be performed to ensure success. Standardized sequential bitewing radiographs over a 10-year interval of four patients who had sealed composite restorations placed without caries removal were digitized and analyzed using the CADIA algorithm. CADIA values for the 10-year period were analyzed using Analysis of Variance (ANOVA), and showed no significant change in radiographic density for this interval (P > 0.05), which is suggestive of arrested dental caries.

A clinical study was designed to examine whether the Philips OrthOralix SD (Gendex Dental Systems, Monza, Italy) orthogonal panoramic projection could improve diagnostic accuracy over standard projections in the detection of proximal surface caries. Thirty-five sets of radiographs that demonstrated optimal image characteristics were selected. Using a five-point scale, 18 viewers evaluated whether specified lesions were present or absent. Viewer data was then compared with a consensus radiographic assessment of the state of the proximal areas. Receiver operating characteristic curves were generated with the use of a maximum-likelihood method of fit. The area under the receiver operating characteristic curve was used as the index of diagnostic accuracy. The mean receiver operating characteristic areas for orthogonal and standard projection panoramic and bite-wing radiography to detect the presence of proximal dental caries were 0.68 +/- 0.03, 0.69 +/- 0.03, and 0.79 +/- 0.03 respectively. Critical ratio analysis was used to compare the means for all possible pairings of imaging modalities. In overall performance, conventional bite-wing radiographs gave a significantly greater diagnostic yield for proximal caries than the Philips OrthOralix SD orthogonal or standard panoramic modalities (p > 0.05). The orthogonal projection did not improve diagnostic accuracy in the detection of proximal carious lesions compared with the standard projection.

The detection of proximal surface caries by the visual interpretation of bitewing radiographs is known to be relatively inaccurate. The present study was designed to examine whether computer image processing could improve the diagnostic accuracy. A computer-aided, software-driven, TV-based system was used to digitize conventional radiographs and digitally process the images using histogram equalization and grey-scale inversion to enhance the images. The computer-enhanced images were compared with conventional intra-oral radiographs for the detection of proximal surface caries using receiver operating characteristic analysis. The results indicate that the digital image processing techniques used did not improve the diagnostic accuracy of dental radiographs. No significant difference in diagnostic accuracy could be detected between the non-enhanced digital images and conventional film-based images for the detection of proximal surface caries.

The diagnostic accuracy of digital subtraction radiography in detection of artificial recurrent caries lesions was assessed in this project. The use of digital subtraction radiography has been shown to markedly increase the accuracy of the detection of destruction in the periodontal bone, but the method has not been evaluated in secondary caries detection. Defects of three different sizes, simulating recurrent caries, were sequentially prepared in the interproximal cavity preparation margins of 28 teeth. Two composite restorative materials with different radiographic densities were used as posterior restorations, and a radiograph was obtained of each defect size and restorative material. The radiographs were digitized and subtracted from the reference images, and the conventional radiographs and the subtraction images were evaluated by seven observers. The data were analysed with ROC statistics. Subtraction radiography was found to be superior to conventional radiography in recurrent caries detection, mainly by reducing the false-positive diagnoses. The radiopacity of the restorative material had a significant effect on accuracy with conventional but not with subtraction radiography.

Background: Diagnostic subtraction radiography (DSR) is a new digital radiographic image subtraction method designed to enhance detection of crestal or periapical bone density changes and to help evaluate caries progression in teeth. In this clinical study, the performance of the DSR method was evaluated for its ability to detect periodontal bone loss and was compared with that of conventional evaluation of radiographs and the standardized cephalostat-guided image acquisition and subtraction technique (LRA) which served as the "gold standard." Methods: In each of 25 subjects with alveolar crestal bone loss created by periodontal surgery, one set of DSR radiographs and one set of LRA radiographs were obtained before and after the surgery. Subtraction images were then generated by both the proprietary DSR and the LRA techniques. Four viewers evaluated the paired film sets and both subtraction image sets using a 5 point confidence scale to determine the presence or absence of crestal bone loss. Receiver operating characteristics (ROC) statistical procedures were applied to analyze the diagnostic accuracy and statistical differences between the three imaging modalities. Results: The DSR subtraction viewing generated an ROC area of 0.882. For 2 of the viewers this represented a statistically significant gain (P <0.05) over the conventional viewing of the radiographs which had an average ROC area of 0.730. In comparison, the LRA method achieved an area of 0.954. The differences between the LRA and the DSR subtraction methods were not statistically significant, but the statistical power for claiming equality was low ranging from 0.2 to 0.6. Conclusions: The use of the DSR technique in clinical radiographic image acquisition and subsequent subtraction analysis clearly enhanced the accuracy of alveolar crestal bone loss detection when compared to conventional film viewing. Because this methodology is less resource demanding than LRA and the film exposure techniques and computer-based image analysis skills may be acquired with only a few hours of training, the DSR has potential in clinical practice. [ABSTRACT FROM AUTHOR]