Fourier Transform–Raman and Reflectance Studies on Dental Enamel Bleached with Hydrogen Peroxide Activated Using a Light-Emitting Diode–Laser System

2009 ◽  
Vol 27 (6) ◽  
pp. 913-919 ◽  
Author(s):  
Ilene Cristine Rosia Cesar ◽  
Luís Eduardo Silva Soares ◽  
Leandro Procópio Alves ◽  
Airton Abrahão Martin ◽  
Egberto Munin ◽  
...  
2015 ◽  
Author(s):  
L. N. Sinitsa ◽  
V. I. Serdyukov ◽  
E. R. Polovtseva ◽  
A. P. Shcherbakov ◽  
A. D. Bykov ◽  
...  

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 645 ◽  
Author(s):  
Antonio Zuorro ◽  
Roberto Lavecchia ◽  
Marika Michela Monaco ◽  
Giuseppina Iervolino ◽  
Vincenzo Vaiano

The presence of azo dyes in textile effluents is an issue of major concern due to their potential impact on the environment and human health. In this study we investigate the photocatalytic degradation under visible light of Reactive Violet 5 (RV5), an azo dye widely used in the textile industry. A preliminary screening of different titania-based catalysts was carried out to identify the best candidate for RV5 removal. The selected catalyst was then tested in a stirred and aerated lab-scale reactor illuminated with a blue light-emitting diode (LED) source emitting in the wavelength range of 460–470 nm. The effects of pH, catalyst load, and hydrogen peroxide additions on the efficiency of dye removal were evaluated. Under the best conditions (pH 10, 3 g/L of catalyst, and 60 mM hydrogen peroxide), the dye solution was completely decolorized in about 2 h. Overall, the results obtained suggest that the proposed process may represent a suitable method for the removal of RV5 from textile effluents.


2017 ◽  
Vol 10 (04) ◽  
pp. 1730003 ◽  
Author(s):  
Qingkai Yao ◽  
Yu Ding ◽  
Guodong Liu ◽  
Lvming Zeng

Photoacoustic imaging, an emerging biomedical imaging modality, holds great promise for preclinical and clinical researches. It combines the high optical contrast and high ultrasound resolution by converting laser excitation into ultrasonic emission. In order to generate photoacoustic signal efficiently, bulky Q-switched solid-state laser systems are most commonly used as excitation sources and hence limit its commercialization. As an alternative, the miniaturized semiconductor laser system has the advantages of being inexpensive, compact, and robust, which makes a significant effect on production-forming design. It is also desirable to obtain a wavelength in a wide range from visible to near-infrared spectrum for multispectral applications. Focussing on practical aspect, this paper reviews the state-of-the-art developments of low-cost photoacoustic system with laser diode and light-emitting diode excitation source and highlights a few representative installations in the past decade.


Biologicals ◽  
2008 ◽  
Vol 36 (5) ◽  
pp. 303-307 ◽  
Author(s):  
Zainab M. Hussein ◽  
Tarek A. El-Tayeb ◽  
Fekery El-Keraby ◽  
Mohamed A. Harith

2018 ◽  
Vol 19 (2) ◽  
pp. 196-204 ◽  
Author(s):  
Apa Juntavee ◽  
Niwut Juntavee ◽  
Phuwiwat Saensutthawijit

ABSTRACT Aim This study evaluated the effect of light-emitting diode (LED) illumination bleaching technique on the surface nanohardness of various computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic materials. Materials and methods Twenty disk-shaped samples (width, length, and thickness = 10, 15, and 2 mm) were prepared from each of the ceramic materials for CAD/CAM, including Lava™ Ultimate (LV), Vita Enamic® (En) IPS e.max® CAD (Me), inCoris® TZI (IC), and Prettau® zirconia (Pr). The samples from each type of ceramic were randomly divided into two groups based on the different bleaching techniques to be used on them, using 35% hydrogen peroxide with and without LED illumination. The ceramic disk samples were bleached according to the manufacturer's instruction. Surface hardness test was performed before and after bleaching using nanohardness tester with a Berkovich diamond indenter. Results The respective Vickers hardness number upon no bleaching and bleaching without or with LED illumination [mean ± standard deviation (SD)] for each type of ceramic were as follows: 102.52 ± 2.09, 101.04 ± 1.18, and 98.17 ± 1.15 for LV groups; 274.96 ± 5.41, 271.29 ± 5.94, and 268.20 ± 7.02 for En groups; 640.74 ± 31.02, 631.70 ± 22.38, and 582.32 ± 33.88 for Me groups; 1,442.09 ± 35.07, 1,431.32 ± 28.80, and 1,336.51 ± 34.03 for IC groups; and 1,383.82 ± 33.87, 1,343.51 ± 38.75, and 1,295.96 ± 31.29 for Pr groups. The results indicated surface hardness reduction following the bleaching procedure of varying degrees for different ceramic materials. Analysis of variance (ANOVA) revealed a significant reduction in surface hardness due to the effect of bleaching technique, ceramic material, and the interaction between bleaching technique and ceramic material (p < 0.05). Conclusion Bleaching resulted in a diminution of the surface hardness of dental ceramic for CAD/CAM. Using 35% hydrogen peroxide bleaching agent with LED illumination exhibited more reduction in surface hardness of dental ceramic than what was observed without LED illumination. Clinical significance Clinicians should consider protection of the existing restoration while bleaching. How to cite this article Juntavee N, Juntavee A, Saensutthawijit P. Influences of Light-emitting Diode Illumination Bleaching Technique on Nanohardness of Computer-aided Design and Computer-aided Manufacturing Ceramic Restorative Materials. J Contemp Dent Pract 2018;19(2):196-204.


1986 ◽  
Vol 40 (5) ◽  
pp. 691-695 ◽  
Author(s):  
Takayuki Okamoto ◽  
Satoshi Kawata ◽  
Shigeo Minami

A new version of the photodiode array Fourier transform spectrometer for visible spectroscopy is described. In this version, a birefringent interferometer with a Wollaston prism produces a spatial interferogram of the radiation, which is detected by a linear photodiode array. In addition to the merit of having no mechanical moving parts, this spectrometer has the beneficial advantage of the simple and rugged optical setup and alignment due to its common-path and in-line interferometer formation. These advantages lend this spectrometer to field-use applications. Emission spectra of a low-pressure mercury lamp and a light-emitting diode and an absorption spectrum of a didymium glass filter measured by the developed spectrometer are presented.


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