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BioMed Research International
Volume 2016, Article ID 5713962, 6 pages
http://dx.doi.org/10.1155/2016/5713962
Research Article

Transmission of Curing Light through Moist, Air-Dried, and EDTA Treated Dentine and Enamel

1Institute of Dentistry, University of Turku, 20520 Turku, Finland
2City of Turku Division of Welfare, 20520 Turku, Finland
3Department of Oral Development and Orthodontics, University of Turku, 20520 Turku, Finland
4Department of Biomaterials Science and Turku Clinical Biomaterials Centre (TCBC), 20520 Turku, Finland

Received 7 March 2016; Revised 16 May 2016; Accepted 5 June 2016

Academic Editor: Evandro Piva

Copyright © 2016 E. Uusitalo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. This study measured light transmission through enamel and dentin and the effect of exposed dentinal tubules to light propagation. Methods. Light attenuation through enamel and dentin layers of various thicknesses (1 mm, 2 mm, 3 mm, and 4 mm) was measured using specimens that were (1) moist and (2) air-dried (). Measurements were repeated after the specimens were treated with EDTA. Specimens were transilluminated with a light curing unit (maximum power output 1869 mW/cm2), and the mean irradiance power of transmitting light was measured. The transmission of light through teeth was studied using 10 extracted intact human incisors and premolars. Results. Transmitted light irradiance through 1 mm thick moist discs was 500 mW/cm2 for enamel and 398 mW/cm2 for dentin (). The increase of the specimen thickness decreased light transmission in all groups (), and moist specimens attenuated light less than air-dried specimens in all thicknesses (). EDTA treatment increased light transmission from 398 mW/cm2 to 439 mW/cm2 (1 mm dentin specimen thickness) (). Light transmission through intact premolar was 6.2 mW/cm2 (average thickness 8.2 mm) and through incisor was 37.6 mW/cm2 (average thickness 5.6 mm). Conclusion. Light transmission through enamel is greater than that through dentin, probably reflecting differences in refractive indices and extinction coefficients. Light transmission through enamel, dentin, and extracted teeth seemed to follow Beer-Lambert’s law.