VALIDITY OF BITE-WINGS FOR DIAGNOSIS OF SECONDARY CARIES IN TEETH WITH OCCLUSAL AMALGAM RESTORATIONS IN-VITRO

This investigation was carried out to establish the validity of bite-w ing radiographs for the diagnosis of secondary caries in teeth with oc clusal amalgam restorations. One hundred and fifty-nine extracted mola rs with occlusal amalgam fillings and characteristics that might be in dicative of the presence of secondary caries were selected. The charac teristics were a blueish-gray discolouration of enamel, a brownish dis colouration of the amalgam-enamel margin, marginal breakdown of the re storation, and/or deep fissures at the margin of the restoration. The teeth were radiographed in a bucco-lingual direction to obtain images comparable to bite-wings. Subsequently, the crowns were sectioned (700 mum) and glued on plastic sheets. The sections were recorded radiogra phically and then examined by independent examiners. Radiolucencies as well as radiopacities adjacent to the restoration were considered to be caries. The validation of the bite-wing radiographic diagnosis was achieved by comparison with the radiographs of the sections. A sensiti vity of 64% and a specificity of 98% were calculated. Large lesions we re always visible on the bite-wing radiograph (100%), the majority of medium-sized lesions (89%) and 40% of small lesions. Small radiopaciti es were detected more often than small radiolucencies.