Dentin Caries Recording with Schiff's Reagent, Fluorescence, and Back-scattered Electron Image

Abstract

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 Schiff's 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 back-scattered electron images. The caries lesions revealed with Schiff's 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 Schiff's reagent but they were greater. Staining with Schiff's 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 Schiff's reaction but was also related to the change in dentin fluorescence, which seems to be a more sensitive indicator of the caries progression than Schiff's reagent, especially in the early phase of the carious process.