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Proceedings Paper

Calculation of optical properties of dental composites as a basis for determining color impression and penetration depth of laser light
Author(s): Kirsten K. Weniger; Gerhard J. Muller
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Paper Abstract

In order to achieve esthetic dental restorations, there should be no visible difference between restorative material and treated teeth. This requires a match of the optical properties of both restorative material and natural teeth. These optical properties are determined by absorption and scattering of light emerging not only on the surface but also inside the material. Investigating different dental composites in several shades, a method has been developed to calculate the optical parameters absorption coefficient μa, scattering coefficient μs, anisotropy factor g and reduced scattering coefficient μs'. The method includes sample preparation and measurements of transmittance and reflectance in an integrating sphere spectrometer, followed by inverse Monte Carlo simulations. Determination of optical properties is more precise and comprehensive than with the previously used Kubelka Munk theory because scattering can be looked at separated into pure scattering with the scattering coefficient μs and its direction with the anisotropy factor g. Moreover the use of the inverse Monte Carlo simulation not only minimizes systematic errors and considers the scattering phase function, but also takes into account the measuring geometry. The compilation of a data pool of optical parameters now enables the application of further calculation models as a basis for optimization of the composition of new materials. For example, a prediction of the general color impression for multiple layers can be carried out as well as the calculation of the wavelength dependent penetration depths of light with regard to photo polymerization. Further applications are possible in the area of laser ablation.

Paper Details

Date Published: 23 March 2005
PDF: 10 pages
Proc. SPIE 5687, Lasers in Dentistry XI, (23 March 2005); doi: 10.1117/12.585758
Show Author Affiliations
Kirsten K. Weniger, Laser- und Medizin-Technologie GmbH Berlin (Germany)
Gerhard J. Muller, Charite-Universitatsmedizin Berlin (Germany)

Published in SPIE Proceedings Vol. 5687:
Lasers in Dentistry XI
Peter Rechmann D.D.S.; Daniel Fried, Editor(s)

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