ABSTRACT
External root resorption is a clinical problem that often is difficult to detect. Since external root resorption is not detectable clinically, radiographic examination is very important. The objective of this study was to compare diagnostic efficacy of conventional film versus direct digital radiography in detecting simulated root resorptive cavities in vitro. This study was based on observational diagnostic methods. A total of 39 extracted teeth including 10 anterior teeth, 6 canines, 8 premolars, 5 maxillary molars and 10 mandibular molars were selected. Except palatal root of upper molars, each root was divided to apical and coronal halves. Half of these sites were considered as control. Buccal cavities were randomly prepared in the remaining sites by # 1/2, #2, and #4 round burs. Each tooth was imaged twice using a CCD based digital system and an E speed film. Radiographs were taken with 0 And 20 degrees mesial angulation .Six image groups were interpreted by 2 experienced oral and maxillofacial radiologists and one endodontist. Conventional radiographs were observed at 2X magnification by a magnifying glass. Sensitivity, speciflcity, false negative and false positive percentage and also accuracy on each method were analyzed in comparison with golden standard. Agreement among these techniques was expressed as the kappa score. Results: The most sensitive technique was conventional radiography at 2X magnification .Sensitivity of digital radiography and enhanced digital radiography were almost equivalent. The most specific technique was also conventional radiography at 2X magnification followed by enhanced digital radiography. Among all, the highest diagnostic accuracy was in conventional radiography at 2X magnification followed by enhanced digital radiography. Taking images with mesial angulation increased sensitivity and decreased speciflcity in all techniques. Therefore, it did not influence the diagnostic accuracy of conventional and enhanced digital radiography. There was an increased agreement between digital radiographic techniques and digital imaging with enhancement options.[k=0.68]. In detecting external root resorption, diagnostic efficacy of conventional radiography at 2X magnification was more than those in enhanced and unenhanced digital radiograph