Characterization of natural carious lesions by fluorescence spectroscopy at 405-nm excitation wavelength.

We aim to characterize natural caries enamel lesions by fluorescence spectroscopy. Sixty human samples with natural noncavitated caries lesions on smooth surfaces were selected and classified into three groups: dull, shiny, and brown lesions. All the samples were analyzed externally at the natural surface and after hemisectionig internally at the center of the lesion. The lesions were excited with a 405-nm InGaN diode laser and the fluorescence was collected with a single grating spectrometer. Four emission bands (455, 500, 582, and 622 nm) are identified in both sound and carious regions. The area under each emission band is correlated with the total area of the four bands for the sound and carious regions. The detected fluorescence from natural and cut surfaces through the caries lesions is not statistically different for the shiny and dull lesion, but is different [analysis of variance (ANOVA) (p<0.05)] for brown lesion at all emission bands. At the 405-nm excitation wavelength, the area of the fluorescence bands at 455 and 500 nm differ statistically for natural carious lesions and sound tissue.

A preliminary investigation of a spectroscopic technique for the diagnosis of natural caries lesions.

OBJECTIVE: To report the use of spectroscopic analysis of dental fluorescence excited with a blue InGaN laser diode operating at 405 nm. METHOD: The spectra resulting from three classifications of smooth surface non-cavitated caries lesions (dull, shiny, brown) with 20 samples in each group were examined using the ratio of integrated fluorescence intensity in two spectral bands. RESULTS: All lesions demonstrated spectra which were significantly different from sound tooth structure. As expected, the 'brown' lesions demonstrated a significantly different spectral profile from the two white spot lesion classifications. Dull and shiny lesions had significantly different spectral measurements when examining the ratio of the integrated fluorescence in spectral bands between 480-500 and 620-640 nm. CONCLUSION: This method has application for detection of dental caries as well as demonstrating potential application to evaluate lesions which may represent different degrees of caries activity.