Laser induced fluorescence with 2-D Hilbert transform edge detection algorithm and 3D fluorescence images for white spot early recognition.

Abstract

There is a must for non-invasive caries detection method to supplement traditional visual assessment by the clinician before lesion progression reaches a stage requiring invasive therapy. In this paper, the nature of tissue response to light interaction has been used for early diagnosis, using laser induced fluorescence spectroscopy. Human tooth sample was illuminated with He-Ne laser sources (633nm) with energy 5mW. The reflected and emitted spectra of investigated samples were collected using hyperspectral camera to develop multispectral images. The variation of reflected and emitted energy as function in wavelength was employed to generate characteristic spectrum of each tooth tissue. Human teeth caries lesion releases their excess energy by emitting fluorescence light producing chemical footprint signature for each tooth elements and caries state. This non-invasive, non-contact, and non-ionizing hyperspectral imaging system was employed to diagnose and classify different caries types and stages. Reconstructed 3D fluorescence images offered discrimination between enamel and dentin caries at 633nm illumination spectral line; white spot lesion was clearly detected and recognized at far visible and infrared wavelength ranges. This study reports on customized optical imaging system that can offer high sensitivity, high resolution. Optimum stimulating wavelength for early caries detection was reported to be 633nm. This novel approach can offer a full map of caries degree status.