Application of Spatial Frequency Domain Imaging in Early Detection of Dental Caries.

This study employed Spatial Frequency Domain Imaging (SFDI) at a wavelength of 530 nm and a spatial frequency of 0.4 mm-1 to measure the reduced scattering coefficient (μs') of artificially demineralized dental tissues across various demineralization durations. Scanning electron microscope and polarized light microscope were utilized to detect surface morphology and demineralization depth. Results show that μs' of dental tissue increases nonlinearly with demineralization time. μs' of human dental tissue increased from 0.403 to 0.897 mm-1 in 72 h, while that of bovine dental tissue increased from 0.604 to 1.420 mm-1. The demineralization depth of bovine dental tissue increased from 0 to 169.83 μm. Artificial caries models with various demineralization durations showed a positive nonlinear correlation between μs' and depth of demineralization, with a correlation coefficient of 0.9673. It demonstrates SFDI's capability for nondestructive detection of early caries.