B. Angmar-mansson et Jj. Ten Bosch, Quantitative light-induced fluorescence (QLF): a method for assessment of incipient caries lesions, DENTOMAX R, 30(6), 2001, pp. 298-307
Objectives: To review the literature on validation and application of the q
uantitative light-induced fluorescence (QLF) method for quantitative assess
ment of early enamel lesions in vivo and in vitro.
Methods: QLF uses light with wavelengths around 405 nm to excite yellow flu
orescence at wavelengths above 520 nm. Its diagnostic capacity is based on
the mechanism that the intensity of natural fluorescence of a tooth is decr
eased by scattering due to a caries lesion. The equipment, the data process
ing and the interaction between equipment and operator are described.
Results: The method has been validated by many authors; the results are pre
sented and compared. For artificial lesions, the validation line is curved.
For larger mineral losses, the curve is linear with a slope of 10% fluores
cence loss corresponding with a mineral loss of 0.15 kg(.)m(-2). For lesion
s caused by natural caries, it is tentatively concluded that fluorescence l
oss is linear to mineral loss with a slope similar to that of artificial le
sions. Reliability and reproducibility have been tested in vivo and show in
terexaminer values of the interclass correlation coefficient, r, of 0.93 <r
<0.99. Confounding factors are inadequate reconstruction of sound fluoresc
ence values and drying of the lesion before or during measurement. In vivo
application showed that statistically significant changes between different
preventive regimes could be proven in only 6 months of study time.
Conclusion: QLF offers a potential tool to reduce the time needed for clini
cal research. Its objectivity will prove useful in epidemiological surveys.
QLF provides visual and quantitative feedback to patients.