J Korean Acad Conserv Dent.  2002 Mar;27(2):113-121. 10.5395/JKACD.2002.27.2.113.

Comparative study of digital and conventional radiography for the diagnostic ability of artificial proximal surface caries

  • 1Department of Conservative Dentistry, College of dentistry, Chosun University, Korea.


Conventional intraoral radiography continues to be the most widely used image modality for the diagnosis of dental caries. But, conventional intraoral radiography has several shortcomings, including the difficulty of exposing and processing intraoral film of consistently acceptable quality. In addition, radiographic retaking that was the result of processing errors, may result in increased discomfort and radiation dose to the patient. Recently, various digital radiographies substitute for conventional intraoral radiography to overcome these disadvantages. The advantages of digital radiography are numerous. One of advantages is the elimination of processing errors. In addition, the radiation dose for digital system is approximately 20% to 25% of that required for conventional intraoral radiography. Another potential advantage of digital imaging is the ability to perform image quality enhancements such as contrast and density modulation, which may increase diagnostic accuracy. The purpose of this study was to compare the diagnostic ability of artificial proximal defects to conventional intraoral radiography, direct digital image(CDX2000HQ(R)) and indirect digital image(Digora(R)). Artificial defects were made in proximal surfaces of 60 extracted human molars using #1/2, #1, #2 round bur. Five dentists assessed proximal defects on conventional intraoral radiography, direct digital image(CDX2000HQ(R)) and indirect digital image(Digora(R)). ROC(Receiver Operating Characteristic) analysis and Two-way ANOVA test were used for the evaluation of detectability, and following results were acquired. 1. The mean ROC area of conventional intraoral radiography, direct digital image(CDX2000HQ(R))and indirect digital image(Digora(R)) were 0.6766, 0.7538, 0.6791(Grade I), 0.7176, 0.7594, 0.7361(Grade II), and 0.7449, 0.7608, 0.7414(Grade III), respectively. 2. Diagnostic ability of direct digital image was higher than other image modalities. But, there was no statistically significant difference among other imaging modalities for Grade I, II, III lesion(p>0.05). In conclusion, when direct and indirect digital system are comparable with conventional intraoral radiography, these systems may be considered an alternative of conventional intraoral radiography for the diagnosis of proximal surface caries.


Digital; Diagnostic ability; Artificial proximal defects

MeSH Terms

Dental Caries
Image Enhancement
Nitro Compounds
Radiographic Image Enhancement
Nitro Compounds


  • Fig. 1 Contingency table for interpretation of diagnostic tests.

  • Fig. 2 Receiver Operating Characteristic (ROC) curves obtained by five observers for detection of artificial proximal defects (Grade I,II,III) with three imaging modalities(conventional intraoral film, direct & indirect digital image).

  • Fig. 3 CDX2000HQ®: Direct digital image system

  • Fig. 4 Digora®: Indirect digital image system

  • Fig. 5 Geometrically standardized experiemental design. A: tube head of Gendex introral X-ray unit, B: acrylic resin plate to hole block of tooth, C: 2cm thick acrylic block simulating the soft tissue.

  • Fig. 6 Each image of same tooth in conventional intraoral radiograph (A), direct digital image (CDX2000HQ®) (B), indrectdigitalimage(Digora®) (C).


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