Optothermophysical properties of demineralized human dental enamel determined using photothermally generated diffuse photon density and thermal-wave fields

Abstract

Noninvasive dental diagnostics is a growing discipline since it has been established that early detection and quantification of tooth mineral loss can reverse caries lesions in their incipient state. A theoretical coupled diffuse photon density and thermal-wave model was developed and applied to photothermal radiometric frequency responses, fitted to experimental data using a multiparameter simplex downhill minimization algorithm for the extraction of optothermophysical properties from artificially demineralized human enamel. The aim of this study was to evaluate the reliability and robustness of the advanced fitting algorithm. The results showed a select group of optical and thermal transport parameters and thicknesses were reliably extracted from the computational fitting algorithm. Theoretically derived thicknesses were accurately predicted, within about 20% error, while the estimated error in the optical and thermal property evaluation was within the values determined from early studies using destructive analyses. The high fidelity of the theoretical model illustrates its efficacy, reliability, and applicability toward the nondestructive characterization of depthwise inhomogeneous sound enamel and complex enamel caries lesions.

Use of new minimum intervention dentistry technologies in caries management

“…[22][23][24][25] The Canary uses a low power, pulsating laser light to scan teeth for the presence of dental caries. The tooth absorbs the laser light and two phenomena are observed and measured: the laser light is absorbed and then consequently a release of heat occurs.…”

Quantitative remineralization evolution kinetics of artificially demineralized human enamel using photothermal radiometry and modulated luminescence

“…In the present investigation, a 3-layer analysis was implemented in order to simulate the geometrical and histological configuration of initial demineralized and subsequently remineralized lesions ( Figure 2). The justification of the 3-layer model was made using TMR cross-sectional images in this work and in Hellen et al [14]. The fitting of the experimental PTR data to the theoretical model results in the extraction of multiple opto-thermophysical parameters for each effective layer.…”

“…A detailed description of the theoretical model and the multiparameter fitting procedure used in the present study can be found in Hellen et al [14]. Briefly, the model is based on the computational simulation of optical and thermal fluxes within each effective enamel layer considered in the analysis.…”

“…To obtain meaningful information from PTR frequency-scan data and remove any influence of instrumental effects, the experimentally measured signals were normalized against an opaque semiinfinite Glassy Carbon reference sample, as detailed in Hellen et al [14].…”

Highly depth-resolved chirped pulse photothermal radar for bone diagnostics

“…[1][2][3] PT techniques, which make use of the principles of diffusion-wave phenomena, basically examine the resulting thermal or acoustic waves, photoexcited charge carriers, phonons and absorbed or scattered photons in a medium following periodic optical excitation. The successful applications of diffusion-wave science extend over a wide spectrum that covers measurement of thermophysical parameters of solids and fluids, [4][5][6][7] microscopy and tomography, [8][9][10] wide field imaging and thermography, 11,12 non-invasive dental diagnostics, 13 microelectronic metrology, 14 etc. In medicine and biology, both time-and frequency-domain PT analytical methods have been successful for non-invasive measurements of peripheral and subsurface tissue parameters.…”