In vitro quantification of smooth surface caries with DIAGNOdent and the DIAGNOdent pen

Objective. A new generation of the laser fluorescence device, DIAGNOdent, for caries detection and quantification has been introduced recently. It is the DIAGNOdent pen. The aim of this study was to compare the validity and reliability of both laser-based devices, DIAGNOdent and the DIAGNOdent pen, in quantifying smooth surface caries. Material and Methods. The material comprised a sample of 52 premolar teeth extracted on orthodontic indication. The teeth were visually sound or had various stages of non-cavitated carious lesions on smooth surfaces. All teeth were photographed and measured with both DIAGNOdent and the DIAGNOdent pen by two examiners independently. The teeth were then sectioned into 300-mu m slices and analysed under a microscope for verification of lesion depth. Histopathological analyses were performed by two observers to assess lesion depth, which was classified into five categories ranging from sound to dentinal caries. Reliability and validity of the two devices were evaluated in terms of intra-class coefficients and Spearman rank correlation coefficient, respectively. The relation between measurements performed by DIAGNOdent and the DIAGNOdent pen was analyzed using Pearson's correlation coefficient. Results. Both DIAGNOdent and the DIAGNOdent pen had excellent intra-observer agreement and acceptable inter-observer agreement. The correlation with histology for DIAGNOdent and the DIAGNOdent pen ranged between 0.47 and 0.57, although the correlation between DIAGNOdent and the DIAGNOdent pen was high. Conclusions. In this in vitro study, the new laser fluorescence device, the DIAGNOdent pen, showed similar reliability and validity at quantification of smooth surface caries compared to the conventional DIAGNOdent device. Agreement between DIAGNOdent and the DIAGNOdent pen was excellent.