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To date, laser fluorescence has been evaluated in several in vitro studies and in a limited numbers of published clinical studies. QLF has undergone extensive investigation and was reported to be a feasible method for monitoring caries lesions, especially on smooth surfaces. The aim of this study was to determine whether the previously reported laboratory values for laser fluorescence are reproducible under clinical conditions using QLF as a reference standard. A group of 30 adolescents, 13-15 years old, with an active incipient caries lesion on the buccal smooth surface of their lower left first molar (tooth 36) were included in the study. The study was approved by the Ethics Committee at Huddinge Hospital and informed proxy consent were obtained. Images of the test sites were captured with the QLF method, digitally stored until the end of the study, and then analysed with special software (Inspector QLF 1.99m). Following the QLF imaging, the test sites were measured with laser fluorescence (DIAGNOdent device, DD). The measurements were made independently by two operators, using a standardised procedure according to the manufacturer. Spearman´s correlation coefficient was used to determine the correlation between the DD readings and the reference standard QLF/.F. This study shows that on smooth surfaces the DIAGNOdent readings correlated satisfactorily with QLF, with rS values ranging from 0.57 to 0.73, depending on the operator. It is hypothesised that the enhancement of fluorescence in the presence of caries registered by DD is due to disintegration of bacterial metabolism, rather than crystalline disintegration. Because of the closer correlation with mineral content, QLF remains the preferred method for research purposes. |