Digital Subtraction Radiography for Monitoring Dental Demineralization

Abstract

The aim of the present study was to evaluate the assessment of progression of demineralization by digital subtraction radiography. In each of 14 extracted human teeth, 2 approximal enamel demineralization lesions were induced in vitro to simulate dental caries. A modified tunnel preparation with glass ionomer fillings was performed on one lesion of every tooth as a model of caries inhibition. Every week, radiographs were obtained under standardized conditions over a period of 42 days. The radiographs were digitized and calibrated for grayscales. Reference landmarks were chosen and aligned for the different pictures by computer–assisted imaging to adjust the images for projective distortions. The images of the 7th, 14th, 21st, 28th, 35th and 42nd day were subtracted from the baseline radiograph. The mean value of gray values of the subtraction images was calculated and ANOVA tests for repeated measurements and paired t tests were used for statistical analysis. The results of the present study indicate that statistically significant gray level changes due to progression of demineralization could be detected in the radiographic images by subtraction analysis. Differences between glass ionomer–filled and nonfilled lesions failed to reach significance. The introduced method may have the potential to detect and document minute caries progression.

Enamel Surfaces Following Interproximal Reduction with Different Methods

“…This method was used in several previous studies to observe the progression of proximal lesion demineralization, 12 artificial recurrent caries, 14 root resorption, 15 and periodontal lesions. 16 Polishing with finer abrasives is necessary to achieve a subsequent reduction of grooves caused by coarse abrasives.…”

“…The films were developed, fixed, and dried in an automatic processor (XR 24 Nova; Dü rr-Dental, Bietigheim-Bissingen, Germany). After digitizing the radiographs at 1.000 dpi in grayscale mode with a scanner (UMAX Powerlook III, Willich, Germany), a digital subtraction analysis was conducted according to Eberhard et al 12 using the software Photoshop 7.0 (Adobe, San Jose, Calif) and NIH Image 1.34 (National Institutes of Health, Bethesda, Md).…”

Accuracy and Reproducibility of Conventional Radiographic Assessment and Subtraction Radiography in Detecting Demineralization in Occlusal Surfaces

“…However, if a carious lesion has progressed, the difference is seen as either an increase or decrease in pixel values on a more uniform background. By increasing the contrast in this image the caries signal is magnified so that changes can be detected more easily [Eberhard et al, 2000;Wenzel et al, 1993]. In practice, the method has limitations, not least of which is the requirement to maintain projection geometries as uniform as possible when capturing both radiographs.…”

Diagnostic accuracy of proximal enamel subsurface demineralization and its relationship with calcium loss and lesion depth

“…33,34 The capacity of several radiographic methods for the detection of different degrees of enamel demineralization was investigated as well. Nevertheless, they either used subtraction radiography to evaluate the resultant images for detection of enamel demineralization 12,14 or compared the performance of advanced diagnostic methods such as digital imaging fibre-optic transillumination or polarizationsensitive optical coherence tomography for the evaluation of the relationship between lesion depth and diagnostic accuracy. 35,36 Owing to the difficulties in combining quantitative methods for mineral determination and methods for obtaining the radiographic image of the same teeth for visual evaluation, no study can be found correlating the amount of calcium loss, lesion depth and the diagnostic accuracy of digital and conventional radiography for the detection of artificial enamel demineralization.…”

“…The performance of different radiographic methods for the detection of enamel subsurface demineralization was compared previously by many researchers. [12][13][14][15] However, there is no study demonstrating the performance of different intraoral radiographic methods for the detection of artificial enamel demineralization in correlation with the amount of calcium loss and lesion depth. Therefore, the aim of this study was to determine the relationship between the amount of calcium loss, lesion depth and the diagnostic accuracy of the DigoraH Optime (Soredex Corporation, Tuusula, Finland) image plate system and F-speed film (Carestream Kodak, Rochester, NY) for the detection of approximal enamel subsurface demineralization.…”