Conventional versus Direct Digital Radiography for Occlusal Primary Molars Caries

Objectives: This in vitro research, evaluated the accuracy of the direct digital radiographic method compared to the conventional radiographic method in the detection and extension prediction of occlusal carious lesions in primary molars. Methods: The material was composed by 60 primary molars presenting pigmentation and, at least, one suspect site of occlusal carious lesion. Direct digital radiographs were obtained with the Dixi system (Planmeca, Helsink, Finland)and the conventional radiographs with the InSight film (Kodak Eastman Co., USA), both in standard form and identical geometrical conditions. Images of sites randomly chosen at occlusal surfaces were evaluated individually by three radiologists, in ideal conditions for radiographic interpretation and with no access to the resources of imaging manipulation from the digital system. For predicting the extension of the lesions the images were scored, as follows: 0- absence of radiolucency, 1- radiolucency confined to the enamel, 2- radiolucency reaching the limit dentine-enamel, 3- radiolucency reaching the half outer part of the dentine, 4-radiolucency reaching to the half inner part of the dentine. The gold standard was obtained by histological study. The specificity and sensibility of both imaging modalities for detecting the carious lesions were also calculated. Data were compared by the Friedman's test (p£0.05). Results: The scores obtained with conventional radiographic films were similar to those of both direct digital radiographs and gold standard. The scores of digital radiographs were significantly lower than those of gold standard (p=0.029). There were no statistical differences in sensitivity and sensibility within each imaging modality neither between the two imaging modalities. Conclusions: In the conditions of this study, it was concluded that, although presenting sensitivity and sensibility similar to those of conventional radiographic examination, the direct digital radiographic method significantly underestimates the extension of occlusal carious lesions in primary molars.(Fapesp 2006/05692-4)