Comparison of QLF and DIAGNOdent for quantification of smooth surface caries

The aim was to compare the detection end quantification of smooth surface c aries by KaVo DIAGNOdent and quantitative laser/tight-induced fluorescence (OLF) using a laser and a lamp as two different light sources. On 40 premol ar teeth extracted from adolescents, 71 non-cavitated approximal surfaces w ere assessed. For QLF, both mean and maximum fluorescence losses were regis tered. To provide a gold standard for verification, the teeth were then sec tioned and lesion depth, stratified on a five-point scale, was determined b y histopathology and microradiography. The correlation between the gold sta ndard and the two methods was assessed by Spearman's rank correlation coeff icient. The sensitivity and specificity of the methods for detection of smo oth surface caries at D-3 level were also assessed. For lesion depth, corre lation with the gold standard was similar for QLF and DIAGNOdent: about 0.8 5. With respect to dentinal caries detection, sensitivity for DIAGNOdent wa s 0.75 and specificity 0.96, with a cut-off point of 9. The corresponding v alues for QLF were 0.94 and 1, with a cut-off value of 20% of fluorescence loss. Spearman's rank correlation coefficients for enamel mineral loss and QLF and DIAGNOdent, respectively, were 0.76 and 0.67. It was concluded that for quantification of smooth surface caries, the methods are of equal meri t, but for scientific purposes, QLF offers the advantage of closer correlat ion with changes in mineral content. Copyright (C) 2001 S. Karger AG, Basel .