title: Transmission of Curing Light through Moist, Air-Dried, and EDTA Treated Dentine and Enamel.
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 (n = 5). Measurements were repeated after the specimens were treated with EDTA. Specimens were transilluminated with a light curing unit (maximum power output 1869 mW/cm(2)), 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/cm(2) for enamel and 398 mW/cm(2) for dentin (p < 0.05). The increase of the specimen thickness decreased light transmission in all groups (p < 0.005), and moist specimens attenuated light less than air-dried specimens in all thicknesses (p < 0.05). EDTA treatment increased light transmission from 398 mW/cm(2) to 439 mW/cm(2) (1 mm dentin specimen thickness) (p < 0.05). Light transmission through intact premolar was 6.2 mW/cm(2) (average thickness 8.2 mm) and through incisor was 37.6 mW/cm(2) (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.
authors.affiliation: Institute of Dentistry, University of Turku, 20520 Turku, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Uusitalo
authors.affiliation: Institute of Dentistry, University of Turku, 20520 Turku, Finland; City of Turku Division of Welfare, 20520 Turku, Finland; Department of Oral Development and Orthodontics, University of Turku, 20520 Turku, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Varrela
authors.affiliation: Department of Biomaterials Science and Turku Clinical Biomaterials Centre (TCBC), 20520 Turku, Finland.
authors.forename: L
authors.initials: L
authors.lastname: Lassila
authors.affiliation: Institute of Dentistry, University of Turku, 20520 Turku, Finland; City of Turku Division of Welfare, 20520 Turku, Finland; Department of Biomaterials Science and Turku Clinical Biomaterials Centre (TCBC), 20520 Turku, Finland.
authors.forename: P K
authors.initials: PK
authors.lastname: Vallittu
mesh_terms: D065638:Absorption, Radiation; D000388:Air; D001641:Bicuspid / Q000737:chemistry / Q000528:radiation effects; D003738:Dental Cements / Q000737:chemistry* / Q000528:radiation effects*; D003743:Dental Enamel / Q000737:chemistry* / Q000528:radiation effects; D003804:Dentin / Q000737:chemistry* / Q000528:radiation effects; D003890:Desiccation / Q000379:methods; D004492:Edetic Acid / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D008027:Light; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D008422:Materials Testing; D012031:Refractometry / Q000379:methods; D012542:Scattering, Radiation; D014867:Water / Q000737:chemistry
chemical_list: D003738:Dental Cements; D014867:Water; D004492:Edetic Acid