Evaluating the objectivity of caries removal with a caries detector dye using color evaluation and PCR

Objectives This laboratory study evaluated the objectivity of caries removal with a caries detector dye by color and bacterial evaluations. Methods In 41 cases of dentin caries (32 extracted human molars), carious tissues were removed using a caries detector dye. Images of dentin surfaces with color-matching stickers were acquired using a CCD camera, and dentinal tissue samples were collected with new round burs. Corrected L*, a* and b* values (CIE 1976 L*a*b* color system) of dentin surfaces were calculated from the sticker color changes. In addition, bacterial DNA in dentinal tissues was detected by the polymerase chain reaction. Results The intra-class correlation coefficient of the corrected L*, a* and b* values was 0.34, 0.30 and 0.49, respectively. There were significant inter-operator differences (P < 0.05). Seventeen of 41 specimens contained bacterial DNA after caries removal. Conclusions Results showed that objectivity of caries removal using the caries detector dye with visual inspection was low.