DENTIN CARIES RECORDING WITH SCHIFFS REAGENT, FLUORESCENCE, AND BACKSCATTERED ELECTRON IMAGE

After being weaned, the Wistar rats (12) were fed on a sucrose diet for five weeks to induce dental caries. Tetracycline was injected intraperitoneally into 7 of them to label the mineralizing dentin front. Five rats without tetracycline injection were used to verify spontaneous fluorescence. The evidently carious area under one prominent fissure from each mandibular molar hemisected sagittally in the midline was photographed under ultraviolet Light so that autofluorescence would be revealed. The jaws were then stained with Schiffs reagent and photographed under normal light and again under ultraviolet light. The areas of all the lesions were quantified planimetrically as they appeared on the photographs. The mineral contents of the areas were verified with the backscattered electron images. The caries lesions revealed with Schiffs reagent also exhibited a change in the color of the dentin fluorescence regardless of the tetracycline labeling. The areas of these lesions followed the shapes of the lesions stained by Schiffs reagent but they were greater. Staining with Schiffs reagent was repeatable after the specimen was washed with ethanol for a few weeks. The loss of minerals was seen in the areas stained with Schiffs reaction but was also related to the change in dentin fluorescence, which seems to be a more sensitive indicator of the caries progression than Schiffs reagent, especially in the early phase of the carious process.