A Novel Method for Direct Nondestructive Diagnosis of Caries Affected Tooth Surfaces by Laser Multiphoton Ionization

Abstract

& A new nondestructive analytical method for diagnosis of tooth caries is presented. The method is based on the Multiphoton Ionization (MPI) fast conductivity signals measured from tooth surfaces. The signals are acquired for a series of laser wavelengths, thus obtaining full MPI spectra. The results indicate a good correlation between the MPI results and the degree of severity of the caries, as diagnosed using traditional inspection. Moreover, the spectral information can be reduced (using least squares fitting) to a single parameter that provides an objective quantitative estimation of the caries severity. The MPI data can be obtained for tiny points on the dental surface and it is suggested that mapping is possible by scanning method.

Authentication and Testing of Banknotes Using Laser Multiphoton Electron Extraction Spectroscopy (MEES)

“…A rather new and uncommon analytical technology is Multiphoton Electron Extraction Spectroscopy (MEES), which has been based of previous analytical applications of multiphoton ionization under ambient conditions: starting with gas phase applications [5][6][7][8], liquids [9], aerosols [10][11][12], and solid surfaces [13][14][15][16][17][18][19][20][21]. MEES is a quantitative analytical spectroscopy, based on detection of photoelectrons extracted in multiphoton process, as a function of laser irradiation wavelength.…”