detection and characterization of human teeth caries using 2d correlation raman spectroscopy

Background: carious lesions are formed by a complex process of chemical interactionbetween dental enamel and its environment. they can cause cavities and pain,and are expensive to fix. it is hard to characterize in vivo as a result of environmentfactors and remineralization by ions in the oral cavity.objectives: the development of a technique that gives early diagnosis whichis non-invasive, is of crucial importance for publichealth. raman spectroscopy is atechnique that can fulfil these requirements. the main goal of this work was to useraman spectroscopy to differentiate between normal and carious human teethinvivo.the samples used in this study were collected by traditional human teeth.material and method: an in vivo raman spectroscopy system andspecializedfiber optic probe has been designed to obtain spectra from tissue. theseprobesare filtered to reduce the background signal from the fiber optics and the collectionfiberutilizes beam steering to optimize the collection effectiv.results: in order to detect any demineralization and carious versus sound pit andfissure enamel, the spectral data sets are analyzed by the proposed scheme to demonstratethe utility of generalized 2d correlation spectra. potential applications of this2d correlation approach are then explored. the raman spectra in the normal tissueshowed thepresence of vibrational bands in 437.87 cm^-1, 581.89 cm^-1, 953.89 cm^-1and 1054.73 cm-1 with smaller intensity than in the carious spectra. image constructionfrom the peak intensity produced chemical maps of apatite concentration.conclusion: such two-dimensional correlation spectra emphasize spectralfeatures not readily observable in conventional one-dimensional spectra.no correlationis observed in mode-to-mode intensity fluctuations indicating that the changesinmode intensities are completely independent. theoretical calculations provideconvincing evidence that the fluctuationsare not the result of diffusion, orientation orlocal electromagnetic field gradients but rather are the result of subtle variations oftheexcited-state lifetime, energy and geometry of the molecule and producing a signatureresponse for carious detection.