[Relationship between caries detector staining and structural characteristics of carious dentin].

The object of this study was to investigate the relationship between the staining behavior of the carious dentin by the caries detector solution and the structural characteristics of the dentin. Using 160 human extracted caries teeth, the ground and polished sectioned surface and the cutting surface of the caries cavities were prepared. The surface stained by the detector solution was examined by the naked eve, reflecting light microscope, observation of the SEM and determination of the Knoop hardness. The microbial invasion was also observed. 1. The staining front was generally unclear on the sectioned surfaces. 2. The stained area on the polished surface was greater than that on the ground sectioned surface. The cutting surface extended beyond the staining front observed on the polished surface. 3. The detector staining seems to depend on the structural change of the matrix and the tubules of the dentin. 4. In the moderate degree caries lesion, the softening extended deeply in the peripheral portion. In the central portion, the softening was relatively not deep. 5. The softening front always extended beyond the staining front and the microbial invasion was far behind. 6. No microbial invasion was found at the cavity floor stained light pink.