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Article
Study the hardness and temperature changes during tooth bleaching using different Laser Sources

Authors: ZainabM. Abdul-Ameer --- Abdulla K. Abass --- Sinan M. Abdul-Satar
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2010 Volume: 22 Issue: 4 Pages: 41-46
Publisher: Baghdad University جامعة بغداد

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Abstract

ABSTRACT
Background: Today, the processes of teeth bleaching by utilizing oxidation chemical components became a public
and important as a cosmetically operative. Particularly the demanding on these processes increased with the
developing in bleaching techniques, where laser light is used as catalyzer agent to increasing the efficiency and
speed of these processes, and the latter known as office bleaching. In this paper, we evaluate the effect of different
laser wavelengths of bleaching on the surface hardness of the tooth and the temperature rise of the pulp due to the
influence of laser light in conjunction with the bleaching gel.
Materials and methods: Three different laser sources (KTP 532nm, LD 810nm and Nd:YAG 1064nm) were used as
accelerator agent in-office bleaching utilizing Hydrogen Peroxide at 37.5%, where the enamel micro hardness
measurements in the teeth (invitro study) pre and post operative was done.
Results: Then by using analysis of variance (ANOVA-Tukey’s test r = 0.05 ) the results shows there are insignificant
effects on tooth hardness due to the changes in the laser wavelengths in both pre and post bleaching.
Conclusion: Thereafter to evaluate the pulp chamber temperature rise induced by three different light sources
employed in this laser-activated tooth bleaching, the pulp chamber temperature was measured during the radiation
processes and the results shows that the minimum temperature rise was seen at the 532nm. So, we can say that the
KTP (SHG) Nd:YAG laser at the wavelength (532 nm) represent the best choice to use in-office bleaching processes.
Keywords: Hardness, Tooth Bleaching, (SHG) Nd:YAG laser, (J Bagh Coll Dentistry 2010;22(4):41-46).

Keywords


Article
Performance Analysis of Laser Diode Single-End-Pumped Solid State Laser

Authors: Mohammed. J. Abdul-Razak --- Hisham .M. Ahmed --- Abdulla. K. Abass
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2013 Volume: 21 Issue: 4 Pages: 1359-1363
Publisher: Babylon University جامعة بابل

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Abstract

In this work, results are presented for a continuous wave diode laser single-end-pumped Nd:YVO4 laser with maximum output power of 240mW in the TEM00 mode at an optical pump power of 850mW. The laser performance under different output couplers has been studied both analytically and experimentally. The theoretical analysis provides a good prediction of the laser performance parameters which are in broad agreement with the experimentally observed results. An optical to optical conversion efficiency of 28% and an average optical slope efficiency of 29% were obtained. The fluctuation of the output power is less than 1.5% in 10 min.

تم في هذا العمل عرض نتائج ليزر Nd:YVO4 مستمر الموجة ومضخ طولياً بواسطة ليزر الدايود. حيث بلغت أعظم قدرة خارجة لهذا الليزر 240mW بنمط كاوسي TEM00 عند قدرة ضخ بصرية قدرها 850mW. تمت دراسة أداء الليزر عملياً وتحليلياً باستخدام مرآيا اقتران خرج ليزري ذات انعكاسيات مختلفة ، لقد أعطى التحليل النظري تكهناً جيداً لمعلمات أداء الليزر وكانت النتائج النظرية في تطابق جيد مع النتائج المقاسة عملياً بكفاءة تحويل بصرية- بصرية بلغت 28% وبمعدل كفاءة ميل بصرية 29%. وقد بينت الحسابات إن التذبذب الحاصل في القدرة الخارجة كان أقل من 1.5% خلال 10 دقائق.


Article
Gain Characteristics for C-Band Erbium Doped Fiber Amplifier Utilizing Single and Double-Pass Configurations: A Comparative Study
دراسة مقارنة لخصائص الربح للمضخمات ذات اشكال المرور المنفرد والمزدوج لليف البصري المطعم بايونات الاربيوم

Authors: Abdulla. K. Abass --- Mohammed J. Abdul-Razak --- Mohammed A. Salih
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2014 Volume: 32 Issue: 9 Part (A) Engineering Pages: 2165-2173
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

An erbium doped fiber amplifier in the conventional communication window utilizing single and double pump pass configurations were demonstrated and compared using OptiSystem 12 software. Both of gain level and gain profile were improved in double-pass configuration utilizing broadband optical mirror. The maximum gain in both single and double-pass configurations are about 36.83dB and 50.1dB respectively, which represents a 37.13% improvement in gain level with double-pass configuration. In addition, a 25mW pump power in double-pass configuration can provide the same gain level in a single-pass configuration at a pump power of 100mW and an input signal power of -20dBm at 1530nm. This represents a pump power conservation of about 25%. The results show that the double-pass amplifier produces a higher noise figure than the single-pass configuration, but still in suitable level less than 6dB.

تم اجراء عرض ومقارنة للمضخمات ذات اشكال المرور المنفرد والمزدوج عند نافذة الاتصالات البصرئية التقليدية لليف البصري المطعم بايونات الاربيوم باستخدام برنامج (OptiSystem12) . لقد تم تحسين كل من مستوى وشكل الربح للمضخمات ذات شكل المرور المزدوج باستخدام المرايا البصرية ذات النطاق الواسع. اقصى ربح للمضخمات ذات اشكال المرور المنفرد والمزدوج كانت بحدود 36.83 ديسبيل و 50.1 ديسبيل على التوالي والتي تمثل تحسيناً بمقدار 37.13% لمستوى الربح باستخدام المضخمات ذات شكل المرور المزدوج. كذلك يمكن للمضخمات ذات شكل المرور المزدوج عند قدرة ضخ 25 ملي واط تجهيز نفس مستوى الربح للمضخمات ذات شكل المرور المنفرد عند قدرة ضخ 100 ملي واط. النتائج اظهرت ان الضوضاء المتولدة في مضخمات المرور المزدوج هو اعلى من الضوضاء المتولدة في مضخمات المرور المنفرد ولكن عند حد مناسب واقل من 6 ديسبيل


Article
Thermal Lensing Reduction in Conventional and Composite Nd:YAG Laser Rod

Authors: Mohammed Jalal AbdulRazzaq --- Abdulla K. Abass --- Wail Yas Nassir
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 11 Part (A) Engineering Pages: 2031-2035
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

A finite-element method (FEM) wasused to simulate numerically the effect of thermal lensing in YAG rods doped with Nd ion using LASCAD software. The temperature distribution and thermal lensing focal length of the composite laser rod (YAG/Nd:YAG) with one undoped end cap was considered and compared with conventional laser rod (Nd:YAG) by applying software. Results show that thermal lensing effects were reduced by a factor of 2 using (YAG/Nd:YAG) composite rod at pump power of 20W.

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