Control of the optical properties of gum and dentin tissue of a human tooth at laser spectral lines in the range of 200–800 nm

A change in the optical properties of the tissue of the gums and dentin of a human tooth is experimentally investigated in vitro with the application of a 99.5% glycerol solution. The kinetics of the total transmittance in the spectral range of 200–800 nm on characteristic laser lines is studied. It is shown that the effectiveness of optical clearing, expressed as a relative increase in the total transmittance, for gum tissue in the laser radiation range of 200–800 nm can vary significantly (by an order of magnitude). In this case, the absolute values of optical transmittance in the UV region are relatively small due to the strong absorption by the endogenous chromophores of the studied tissues, and in the visible and NIR regions, on the contrary, they are significant, which is due to the absence of strongly absorbing chromophores. The effectiveness of dentin clearing in the entire visible and NIR spectral regions is on average 25% for 300 minutes of immersion of the sample in a 99.5% glycerol solution. The presented results are necessary for increasing the efficiency of laser therapy and methods for optical monitoring of morphological changes in biological tissues for the purpose of early diagnosis of diseases.