Correlation between laser fluorescence readings and volume of tooth preparation in incipient occlusal caries in vitro

This study evaluated the correlation between laser fluorescence readings and the extent of carious tooth structure as measured by the volume of tooth preparation in vitro. One hundred and three permanent molars and premolars containing incipient occlusal caries were selected. DIAGNOdent and QLF readings were obtained according to manufacturer instructions. Caries was removed with ¼ round burs in high speed. The amount of uncured composite needed to fill the prepared cavity was used to calculate the volume of tooth preparation. The Pearson correlation for preparation volume and maximum DIAGNOdent reading and QLF measurements was 0.285 and 0.399 respectively. Sensitivity and specificity of DIAGNOdent was .83 and .60 and .66 and .73 for the cut-off values of 20 and 30 respectively. Within the limitations of this study, it is possible to conclude that laser fluorescence measured with DIAGNOdent and QLF does not appear to correlate well with tooth preparation volume.