Efficacy of Three Caries-staining Agents

To avoid excessive excavation of carious dentin, we developed a caries-detecting agent composed of polypropylene glycol to stain caries-affected dentin. The purpose of this study was to evaluate the new agent by examining the characteristics of the dentin surface after removal of carious dentin. Eight extracted human teeth with dentin caries were used. The teeth were longitudinally sectioned through the center of the caries and micro Vickers hardness (MVH) was measured from the pulpal wall to the caries cavity every 200 μm. Carious dentin was then removed using a steel bur following Caries Check (Nishika, Yamaguchi, Japan) staining. After removal of the stained dentin, the MVH of the dentin was determined by observing the indentation on the dentin; the DIAGNOdent value (D-value) was measured using DIAGNOdent (Kavo, Biberach, Germany). Then a new caries-staining agent (Discover RED, Phoenix Dental, Inc., Fenton, MI, USA) was applied in the cavity, the stained dentin was removed, and the MVH and D-value were measured. Finally, such procedures were repeated using Caries Detector (Kuraray, Tokyo, Japan). After the final measurements, the microstructure of the dentin cavity wall was observed by scanning electron microscopy. The differences in the MVH and D-value between using Caries Detector and Discover RED were not significant. However, the differences in the MVH and D-value between the Caries Check and the other two methods were significant. Caries Check may be the most useful modality for the more precise excavation of carious dentin and preservation of sclerotic dentin.