Comparison of microhardness of caries detector dye stained and unstained dentin

Rangsima Sakoolnamarka, DDS, PhD, Nitiwadee Krinpakdee, and Tawatchai Bannakij

Department of Operative Dentistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand

Purpose: To evaluate microhardness of stained and unstained carious dentin which was differentiated by two caries detector dyes (Caries Detector and Sable Seek). Further, to compare the ability of the two dyes in recognizing caries-infected dentin.
Materials and Methods: Forty human molars with occlusal caries were sectioned longitudinally through the lesions in the mesio-distal plane and polished with aluminium oxide paste. Half of the specimens were stained with Caries Detector, and the remaining with Sable Seek. The specimens were microhardness tested using a Knoop microhardness indenter. The mean hardness values from each group were calculated and compared using one-way ANOVA and t-test.
Results: The mean microhardness values of dye-stained dentin from Caries Detector and Sable Seek groups were 9.99 and 7.93 KHN, respectively, which were significantly lower than those of unstained dentin (20.25 for Caries Detector group and 19.24 for Sable Seek group). There was no significant difference between microhardness values obtained from unstained carious dentin determined by the two caries detector dyes.
Conclusion: The hardness values of dye-stained dentin were lower than those of the unstained area. The ability of Caries Detector and Sable Seek in differentiation of the two layers of carious dentin was not different when dentin hardness was the only considered criterion. (Int Chin J Dent 2006; 6: 49-52.)

Key Words: carious dentin, caries detector dye, microhardness.