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Published on: August 15, 2018
Determination of the spectrally resolved extinction coefficient of human dental enamel using collimated transmission
Karsten Pink1, Sascha Hein2, Florian Foschum3
1Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholzstr. 12, 89081 Ulm, Germany; Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
Objectives:
The determination of the extinction coefficient of human dental enamel to deliver further optical properties of enamel to improve the understanding of light propagation in teeth and to improve restoration materials.
Methods:
The extinction coefficient was measured within a spectral range of 300-980 nm using a collimated transmission setup. 35 specimens from 16 donors were examined. The donors were categorized by age and the researched specimen were categorized by tooth type, tooth quality and lateral expansion of the enamel to clarify the influence of these parameters.
Results:
The obtained spectrally resolved extinction coefficient was accurately described by a power law, which agrees with theoretical scattering models. The results were evaluated with regard to the influence of parameters such as subject age, tooth type, enamel sample quality and enamel width. For this purpose, both the average values of multiple measurements of a single sample in a defined spectral range as well as the curve slope of the averaged results versus wavelength were compared.
Significance:
The results provide detailed information about the optical properties of human enamel. The wide spectrum investigated provides important information for the evaluation of the main scatterers and the optical impression under any light condition. However, the deviation of the extinction coefficient varies less between the mean values for the specimens grouped by several parameters than between the specimens themselves within a group. This indicates a unique optical behaviour for every specimen and this requires consideration in the development of artificial materials.
