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Article
The effect of the CO2 laser on the enamel cracks

Author: Dr. Muthenna Sh. Rajab. *
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2008 Volume: 5 Issue: 2 Pages: 148-153
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The objective of this study aimed to assess the effeats of the CO2 laser on the enamel cracks. The labial cracks of thirty extracted central incisors were irradiated with 4 Watts power and (0.4, 0.2 and 0.1) pulse durations. The laser used was CO2 laser with 10.6 μm in wavelength. The irradiated samples were sectioned into ground cross sections and examined under polarizing microscope. Enamel cracks can not be welded completely using CO2 laser irradiation. Although the formation of superficial glaze layer, there was a tendency to increase in the separation of the crack sides as the pulse duration of the laser increased

Keywords

Keywords: Enamel --- Crack --- CO2 --- Laser


Article
Root Caries Prevention Potential of Chopped CO2 Laser: an In Vitro Study

Author: Dr. Muthenna Sh. Rajab.* د.مثنى رجب
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2008 Volume: 5 Issue: 1 Pages: 1-6
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The objective of this study aimed to assess the caries-preventive potential of various chopped CO2 laser parameters, and to explore the effect of the laser energy density on the caries inhibition activity.Roots of extracted human premolar teeth were irradiated with three various energy densities (25.47, 50.93, and 101.86) J/cm2, by changing the number of pulses, the pulse duration, and the spot diameter. The CO2 laser system emitted laser with 10.6m in wavelength. All roots were subjected to carieslike lesion formation by 3.5 pH lactic acid for 21 days. The roots after that were sectioned into ground cross sections and the lesion depths were measured under a polarizing microscope.Chopped CO2 laser preventive treatments inhibited carieslike lesion progression up to 36%. This effect was improved with decreased total energy density within the limits of the examined laser parameters.

Keywords

Keywords: Root --- Caries --- Chopped --- CO2 --- Laser


Article
The Effect of Laser Irradiation on the Thickness of the Caries Surface Zone

Authors: Dr. Hikmet A. Sh. Al-Gharrawi.* د.حكمت عبد الرحيم --- Dr. Muthenna Sh. Rajab.* د.مثنى رجب
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2008 Volume: 5 Issue: 2 Pages: 137-141
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The objective of this study aimed to assess the relation between various CW CO2 laser parameters and the thickness of the surface zone in the created carieslike lesion.A total of twenty four extracted human premolar teeth were irradiated with three various power densities (63.66, 31.83, and 15.9) W/cm2. The CO2 laser system emitted laser with 10.6m in wavelength. All samples were subjected to 3.5 pH lactic acid for 21 days to form carieslike lesion. The crowns after that were sectioned into ground cross sections and the surface zone thicknesses were measured under a polarizing microscope.Continuous wave (CW) CO2 laser had a noticeable effect on the prominence of the surface zone. The mean of the surface zone thicknesses found to be directly related to the power density of CW CO2 laser.

Keywords

Keywords: Surface --- Zone --- Caries --- CW --- CO2 --- Laser


Article
DESIGN AND ANALYSIS OF SOME PARAMETERS FOR CO2 LASER BEAM EXPANDER

Author: Alwan M. ALwan
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2008 Volume: 11 Issue: 1 Pages: 68-73
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

In this paper, design analysis and optimization of beam expander device and by using computer software (Zemax). The laser beam source associated with the suggested designs of the optical system is that of the TEA CO2 laser working at 10.6µm. The optical beam expander is a Galilean design and configured two ZnSe lenses.

في هذا البحث تم تصميم موسع حزمة الليزر والذي يمثل المنظومة البصرية في هذا التصميم والتي تم تحليلها باستخدام نظام Zemax البرمجي للحصول على أفضل تصميم باستخدام حزمة ليزرية ذات شدة عالية.ان النتائج التي تم الحصول عليها من خلال دراسة متغيرات موسع الحزمة أثبتت إمكانية تقليل الزيغ الكروي من خلال إضافة عدسات إلى التلسكوب البصري بالاعتماد على التحليل البرمجي لنظام Zemax


Article
PREPARATION AND ACTIVITY TEST OF THE CATALYST USED IN CARBON DIOXIDE LASER OF SEALED TUBE
تحضير وفحص فعالية العامل المساعد المستخدم في ليزر ثنائي اوكسيد الكاربون ذو ألأنبوبة المغلقة

Author: Karim H Hassan كريم هنيكش حسن
Journal: Journal of Research Diyala humanity مجلة ديالى للبحوث الانسانية ISSN: 1998104x Year: 2008 Issue: 29 Pages: 125-135
Publisher: Diyala University جامعة ديالى

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Abstract

A new catalyst composing of a mixture of CuO-ZnO-Al2O3 was prepared. Testing of it in a pilot plant showed that it can be used in the oxidation of CO to CO2. Using of the catalyst in the sealed CO2 laser unit indicated that it is very useful in this respect as the laser reserved its activity and power.

تم العمل على تحضير عامل مساعد يتكون من نسب معينة من اوكسيد النحاس- اوكسيد الخارصين واوكسيد ألألمنيوم. أجريت عملية فحص للعامل المساعد باستخدام وحدة ريادية لهذا الغرض حيث بينت النتائج إن العامل المساعد يتمتع بكفاءة عالية لتحويل أحادي اوكسيد الكاربون إلى ثنائي اوكسيد الكاربون.أظهرت نتائج استعمال العامل المساعد في وحدة ليزر ثنائي اوكسيد الكاربون المغلقة امكانبة استعماله مع المحافظة على القدرة الجيدة والمطلوبة لليزر

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