Detection of occlusal caries without cavitation by visual inspection, film radiographs, xeroradiographs, and digitized radiographs.

The study compared visual inspection, conventional film radiographs, xeroradiographs, and digitized radiographs for the detection of caries in occlusal surfaces without cavitation. 166 extracted premolars and permanent molars without macroscopic cavitation were included. Eight observers assessed five grades of occlusal caries by visual inspection and by the three imaging techniques. Histologic sections (700-1,000 microns) served as validating criterion for the presence and depth of carious lesions, 82 teeth being found carious (27 with deep dentinal involvement) and 84 being scored as sound. Approximately 20% of the dentinal carious lesions were detected by visual inspection and 40% by conventional film radiography (both with a minimal number of false-positive observations). By xero- and digital radiography, an increasing number of false-positive scorings was seen. By digital radiography the true-positive detection rate was similarly increased to 60%. The predictive values of a positive test were, on average, 0.85 for visual inspection, 0.89 for film, 0.78 for xero-, and 0.82 for digital radiography and for a negative test 0.56, 0.61, 0.61, and 0.69, respectively. However, digital radiography was able to detect over 70% of deep dentinal lesions in contrast to 45% by the other two imaging methods, without an increase in false-positive diagnoses of truly caries free teeth, compared with the other techniques.