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Article
The effect of silanized alumina nano -fillers addition on some physical and mechanical properties of heat cured polymethyl methacrylate denture base material

Authors: Ban Saad Jasim بان سعد جاسم --- Intisar J. Ismail انتصار جميل اسماعيل
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 2 Pages: 18-23
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Polymethyl methacrylate (PMMA) is the most commonly used material in denture fabrication. Thematerial is far from ideal in fulfilling the mechanical requirements. Midline fracture; poor thermal conductivity andwater sorption, are common problem in this material. The purpose of this study was to evaluate the effect of additionof surface treated Aluminum oxide nano fillers on some properties of heat cured (PMMA).Materials and methods: In addition to controlled group of heat cured PMMA the silanized (Al2O3) nanoparticles wasadded to PMMA powder by weight in three different percentages 1wt%, 2wt% and 3wt%, mixed by probe ultrasonicationmachine. 200 specimens were constructed and divided into 5 groups according to the test (each groupconsist of 40 specimens) and each group was subdivided into 4 sub-groups. The tests conducted were thermalconductivity, thermal diffusivity, transverse strength, indentation hardness (shore D), surface roughness, water sorptionand solubility. The results were statistically analyzed using ANOVA and Dunntt t-test.Results: A highly significant increase in transverse strength was observed with the addition of (Al2O3) nanoparticles to(PMMA) at the percentage of 1wt%, the value was 117.72 Mpa and significant increase at 2wt%; while a significantreduction occurred in transverse strength at the percentage of 3% the value was 90.110 Mpa. A significant increasein surface hardness and non significant differences in surface roughness were observed for all percentages.Conclusion: The addition of Al2O3 nanoparticles to acrylic resin improves the thermal properties and transversestrength of acrylic resin at the same time this addition decreases water sorption and solubility


Article
Effect of etchant type and the use of silane on the shearbond strength of composite resin to porcelain.

Author: Abdulla MWAl-Shamma عبد الله محمد وجيه الشماع
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2011 Volume: 23 Issue: 4 Pages: 1-6
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: This study was formulated to compare the effect of 5%hydrofluoric acid in comparison to37%phosphoric acid with and without the application of silane on bond strength of composite to porcelain.Materials and Methods: Specimen preparation was divided in to two phases, metal-disks fabrication (8mm-diameterand 4mm-thickness) and ceramic veneering. Thirty two specimens were prepared, sandblasted with 50 μm aluminumoxide, and divided into four groups of eight samples. Groups I and III were etched with 37%phosphoric acid whilegroups II and IV were etched with 5%hydrofluoric acid; and groups I and II were silaneted while groups III and IV werenot. Heliobond, and resin composite were applied to each specimen using a plastic transparent split mold (4mmdiameterand 4mm-height). Specimens were stored in distilled water for 24 hours then thermocycled for 100 cycles.Shear bond strength was determined by a Zwick universal machine at a cross-head speed 5 mm/minute.Results: Mean shear bond strength values were 21.02(group I), 23.31(group II), 4.00(group III), and 18.60(group IV).Paired-t revealed that specimens treated with 5%hydrofluoric acid were significantly higher than those treated with37%phosphoric acid regardless the use of silane. The use of silane dramatically enhanced the bond strength ofcomposite resin to porcelain for both acids. All specimens treated with 37%phosphoric acid without silane showedadhesive failure, while those treated with 5%hydrofluoric acid showed mostly cohesive failure within ceramic.Conclusion: Silane improved the shear bond strength of composite to ceramic, and hydrofluoric acid performedgreater bond strength compared to phosphoric acid.


Article
Shear bond strength of stainless steel brackets bonded to porcelain surface treated with 1.23% acidulated phosphate fluoride gel compared to hydro fluoric acid with silane coupling agent (In vitro comparative study)

Authors: Tariq M. M. Al-Najjar طارق النجار --- Fakhri A. Ali فخري عبد علي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: special issue 1 Pages: 167-173
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: With the increasing demands for adult orthodontics, a growing need arises to bond attachments toporcelain surfaces. Optimal adhesion to porcelain surface should allow orthodontic treatment without bond failurebut not jeopardize porcelain integrity after debonding.The present study was carried out to compare the shear bondstrength of metal bracket bonded to porcelain surface prepared by two mechanical treatments and by usingdifferent etching systems (Hydrofluoric acid 9% and acidulated phosphate fluoride 1.23%).Materials and Methods: The samples were comprised of 60 models (28mm *15mm*28mm) of metal fused to porcelain(feldspathic porcelain). They were divided as the following: group I (control): the porcelain surface left untreatedand glazed, group II (Diamond bur group): the porcelain surface was treated with fine diamond bur at speed of350000 rpm for 20 seconds, group III (Red stone bur): the porcelain surface was treated with coarse red stone bur atspeed of 8500 rpm for 20 seconds. Each group consists of 20 samples, then each group subdivided into twosubgroups; one treated with acidulated phosphate fluoride 1.23% and the other subgroup treated with Hydrofluoricacid 9 % with silane coupling agent.Results: The result of this study revealed that there was very high significant difference among all tested groups andthe highest shear bond strength was for diamond bur group with HFA and Silane (8.67 MPa), the 2nd highest strengthwas for control group with HFA and Silane (7.52 MPa), the 3rd was (7.38 MPa) in red stone bur with HFA and Silane,the least shear bond strength values were obtained for subgroups treated with acidulated phosphate fluoride gel1.23%.Conclusions: The most reliable procedure for bonding orthodontic brackets to the porcelain surfaces is through thesurface treatment combinations of mechanical roughening by using diamond bur, 9% Hydrofluoric acid and Silanecoupling agent application


Article
The Effects of 2 Types of Cements and 2 Types of Surface Treatments on Shear Bond Strength of Zirconia

Author: Maha A Al-Murad
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 3 Pages: 473-481
Publisher: Mosul University جامعة الموصل

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Abstract

The aim of this study is to evaluate the interactive influence of different types of cement and surface treatments on bond strength of zirconia. Materials and Methods: Thirty cylindrical zirconia blocks (Diameter4mm& thickness4mm)were fabricated for the study. All the specimens were ground with 600 grit silicone carbide polishing paper. Zirconia specimens were randomly divided into three main groups. 1stcontrol (600grit) no surface treatment. 2ed the specimens were air-abrasion with 50um aluminum oxide particles (Al2O3). 3 rd the specimens were air-abrasion with 50um aluminum oxide particles (Al2O3)+ silane .Then ,each group was divided into two groups according to the luting cement used which are( Reinforcd glass ionomer cement and dual cure resin cement).The zirconia blocks bonded to the composite blocks using these types of cements. Then each pair of zirconia block and composite was applied to load of( 15 Kg) for 15 minutes in order to standardized the applied pressure for each type of cement . The resin cement was then light polymerized for 30s with LED light at 500mW/cm2 (Ledition, Ivoclar Vivadent, Liechtenstien) at the distance of 1mm from each direction. The specimens were stored for 24 hours at 37℃. Shear bond strength was measured by using Universal Testing Machine, and mode of failure examined by a stereomicroscope. Results: All the zirconia blocks were bonded to the composite blocks by self adhesive resin cement revealed results more preferable than zirconia blocks were bonded to the composite blocks by Reinforced glass ionomer cement. The shear bond strength between Zirconia and self-adhesive resin cement for the surface were treated with Aluminum-oxide air abraded alone, and zirconia surface were treated with Aluminum-oxide air abraded + silane more preferable than shear bond strength cement between Zirconia and Rinforeced glass ionomer cement for the surface were treated with Aluminum-oxide air abraded alone, and zirconia surface were treated with Aluminum-oxide air abraded + silane. Conclusion: Zirconia was more durable with Self-adhesive resin cement than Reinforced glass ionomer cement. Zirconia Surface treatments were very critical for improvement bond strength with cement in addition to the properties of that cement


Article
Effect Of Rubber Treatment On Compressive Strength And Thermal Conductivity Of Modified Rubberized Concrete
اثر معاملة المطاط على المقاومة الانضغاطية والموصلية الحرارية للخرسانة الممططة المدلة

Authors: Dina Mukheef Hamza دينا مخيف حمزة --- Rana Hashim Ghedan رنا هاشم غيدان
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2011 Volume: 15 Issue: 4 Pages: 21-29
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Waste tires have been studied widely for the last twenty years on several applications such as asphalt pavements, water proofing systems and concrete pedestrian block etc. There are several properties of the rubber could be used usefully in this application such as low density and water proofing property etc. On the other hand any undesirable changes in the properties of the material resulted from adding the rubber particles could be improved effectively by a certain way. The main aim here is to study the compressive strength and thermal conductivity of the rubberized concrete compared with the traditional one and how it affected by using a coupling agent such as SILAN which is used currently in the present study to treat the particles of rubber. Three patches were prepared. Each one consists of three cubic specimens (15x15x15)cm and two disc specimens (5x1)cm. The first patch was the control concrete, the second was the rubberized concrete, in this one 15% the volume of gravel were replaced by waste tires particles and the third was the modified rubberized concrete in this patch rubber particles were treated with SILAN of 0.1% of water as a coupling agent. Compressive strength and thermal conductivity tests were conducted for the three patches. The overall results show that the adding of rubber particles to the concrete to obtain a lightweight one cause a reduction in the compressive strength by about 49.8% from traditional concrete, so to improve this property the SILAN used as a coupling agent to treat the surface of rubber particles and it was found to be very effective in improving the compressive strength so that this strength reduced by about 12.9% from traditional concrete. Also, the added rubber particles decreased the thermal conductivity of the rubberized concrete by about 26.7% from traditional concrete while when rubber particles treated with SILAN, thermal conductivity increased by about 17.8% from traditional concrete.

لقد تم دراسة مخلفات الاطارات المطاطية في السنوات الاخيرة بشكل واسع لاستخدامها في الكثير من التطبيقات مثل الارصفة الاسفلتية, الانظمة المانعة لتسرب المياه والبلوكات الخرسانية المستخدمة للارصفة الخ. هناك الكثير من خواص المطاط ممكن استخدامها بشكل مفيد في هذه التطبيقات مثل الكثافة الواطئة وخاصية الحماية ضد تسرب المياه. من ناحية اخرى اي تغيير غير مرغوب به في خواص المادة نتيجة اضافة جزيئات المطاط ممكن اعادة تحسينها وبشكل فعال بطرق معينة. الهدف الاساسي هنا هو لدراسة مقاومة الانضغاط والموصلية الحرارية للخرسانة المطاطية مقارنة بالخرسانة الاعتيادية وكيف تتاثر هذه الخواص باستخدام مادة مثل السيلان المستخدم في هذا البحث لمعالجة المطاط. تم اعداد ثلاث خلطات خرسانية كل خلطة تتكون من ثلاث مكعبات بابعاد (15*15*15) سم وقرصين ذات سمك قليل بابعاد (5*1) سم. الخلطة الاولى خرسانة اعتيادية و الخلطة الثانية خرسانة مطاطية تم فيها استبدال نسبة 15%من الركام الخشن بجزيئات المطاط اما الخلطة الاخيرة فقد تم فيها معالجة سطح المطاط بمادة السيلان بنسبة 0.1% من الماء كمادة تزيد من قوة الترابط بين جزيئات المطاط والخرسانة. تم اجراء فحص الانضغاط و الموصلية الحرارية للخلطات الثلاثة حيث اظهرت النتائج بان اضافة جزيئات المطاط الى الخرسانة لتكوين خرسانة خفيفة الوزن قد ادى الى تناقص مقاومة الانظغاط بمقدار 49,8% عن الخرسانة العادية ولتحسين هذه الخاصية تم استخدام مادة السيلان لمعالجة سطح المطاط ولقد وجد ان استخدام هذه المادة له تاثير كبير في تحسين مقاومة الانظغاط للخرسانة المطاطية المعدلة بحيث ان هذه المقاومة قد تناقصت بنسبة 12.9% عن الخرسانة الاعتيادية. كذلك ان اضافة جزيئات المطاط يقلل من الموصلية الحرارة بمقدار26.7% عن الخرسانة الاعتيادية بينما عند معالجة جزيئات بمادة السيلان فان الموصلية الحرارية سوف تزداد بمقدار 17.8% عن الخرسانة الاعتيادية. ةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةة


Article
The effect of Helium dilution of silane on the structural, optical and electrical properties of hydrogenated nanocrystalline silicon (nc-Si:H) thin films prepared by HW-CVD method
تأثير تخفيف السايلان بالهيليوم على الخواص التركيبية والضوئية والكهربائية للاغشية الرقيقة للنانو سليكون البلوري (nc-Si:H) المهدرج المحضرة بطريقة HW-CVD

Author: Nabeel A. Bakr نبيل علي بكر
Journal: Diyala Journal For Pure Science مجلة ديالى للعلوم الصرفة ISSN: 83732222 25189255 Year: 2012 Volume: 8 Issue: 3 - part 2 Pages: 355-374
Publisher: Diyala University جامعة ديالى

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Abstract

Structural, optical and electrical properties of hydrogenated nanocrystalline silicon (nc-Si:H) films, deposited from silane (SiH4) and helium (He) gas mixture without hydrogen by hot wire chemical vapor deposition (HW-CVD) method were investigated as a function of helium dilution of silane (RHe). We observed that the deposition rate is much higher (4-33 Å/s) compared to conventional plasma enhanced chemical vapour deposited (PE-CVD) nc-Si:H films. Raman spectroscopy revealed that the crystalline volume fraction decreases with increasing He dilution of silane whereas the crystallite size remains almost constant (~ 2 nm) for the entire range of He dilution of silane studied. Furthermore, an increase in the structural disorder in the nc-Si:H films has been observed with increasing He dilution of silane. The hydrogen content was ~ 9 at. % for the film deposited at 60 % RHe and decreases rapidly as RHe increases further. The photoresponse decreases by order of 1 with increasing helium dilution of silane from 60 to 97 %. It has been concluded that adding helium gas to the silane induces the structural disorders in the hydrogenated nanocrystalline silicon (nc-Si:H) thin films prepared by HW-CVD method.

تمت دراسة الخواص التركيبية والضوئية والكهربائية للاغشية الرقيقة للنانو سليكون البلوري المهدرج (nc-Si:H) والمرسب من مزيج غازي السايلان (SiH4) والهيليوم (He) بدون استخدام الهيدروجين بطريقة الترسيب بالبخار الكيميائي باستخدام السلك الساخن (HW-CVD) كدالة لنسبة تخفيف السايلان بوساطة غاز الهيليوم . لقد وجد بان معدل الترسيب اعلى بكثير(4-33 Å/s) مقارنة بالطريقة التقليدية للترسيب بالبخار الكيميائي باستخدام التعزيز بالبلازما (PE-CVD) . طيف رامان بين بان الجزء الحجمي البلوري يقل مع زيادة نسبة التخفيف في حين ان قياس البلورات يبقى ثابتا تقريبا (~ 2 nm) في مدى التخفيف المدروس . كما وجد ان عدم الانتظام التركيبي للاغشية الرقيقة المحضرة بهذه الطريقة يزداد بزيادة نسبة التخفيف . وقد كانت كمية الهيدروجين المحتوى في الغشاء المرسب بحدود (9%) باستخدام نسبة تخفيف مساوية لـ 60% ويقل بشكل سريع بزيادة نسبة التخفيف مما يؤدي الى تدهور في مواصفات الغشاء . كما وجد ان الاستجابة الضوئية تقل بزيادة نسبة التخفيف . تم التوصل من خلال هذه الدراسة الى ان اضافة غاز الهيليوم الى غاز السايلان يؤدي الى زيادة عدم الانتظام التركيبي للاغشية الرقيقة للنانو سليكون البلوري المهدرج والمحضر بطريقة (HW-CVD).


Article
Effect of Mixing Silanized Poly Propylene and Siwak Fibers on Some Physical and Mechanical Properties of Heat Cure Resin Denture Base
تأثير إضافة خليط من ألياف البولي بروبيلين والسواك بعد المعالجة السطحية على بعض الخصائص الفيزيائية و الميكانيكية لقاعدة طقم من الأكريل الحراري

Author: Hanan Abdul-Rahman Khalaf حنان عبد الرحمن خلف
Journal: Al-Mustansiriyah Journal for Pharmaceutical Sciences مجلة المستنصرية للعلوم الصيدلانية ISSN: 18150993 Year: 2016 Volume: 16 Issue: 1 Pages: 26-37
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

PMMA is used in construction of denture base due to several advantages, including biocompatibility and optimal appearance. Operators and patients complain from fracture of acrylic denture base material attributed to decreased resistance to impact, flexural or fatigue stresses. The aim of the research is to assess the effect of addition of silanized mixture of siwak and poly propylene fibers on PMMA denture base.Fourteen acrylic resin specimens were prepared for each test (Impact strength, Transverse strength, Shear bond strength, Thermal conductivity, Shore D hardness, Surface roughness and Water sorption) the specimens were grouped as control group (n=7) :no fibers additive and experimental group (n=7):(2 %) silanized mixture of siwak and poly propylene fibers, 4 mm length, FT-IR was done to investigate the presence of functional groups of coupling agent (TMSPM) on the tested fibers, independent t-test was used for statistical analysis of the resulted data. Statistical analysis indicated that silanized mixture of poly propylene and natural fibers (siwak) produced significant increase (p≤0.05) of impact strength and highly significant increase (p≤0.01) of shear bond strength, transverse strength, thermal conductivity and shore D hardness of heat cure acrylic resin while a non significant increase (p>0.05) of surface roughness and water sorption properties was observed in comparison to non fiber reinforced resin specimens. The addition of silanized mixture of siwak and polypropylene fibers into heat cure PMMA improve the tested physical and mechanical properties.

يستخدم البولي مثيل ميثاكريليت في صناعة قاعدة أطقم الأسنان بسبب العديد من المزايا مثل التوافق الحيوي مع الأنسجة والمنظر الجميل الأمثل ولكن المرضى يعانون من كسر طقم الأكريلك بسبب إنخفاض المقاومة للصدمة وللقوة العرضية.الهدف من هذه الدراسة هو تقييم إضافة خليط من ألياف البولي بروبيلين وألياف السواك الطبيعية المضادة للميكروبات على قاعدة طقم الأكريلك.تم إعداد أربعة عشر من عينات راتنج الأكريلك الحراري لكل من الإختبارات التالية: قوة الصدمة, قوة المستعرضة, التوصيل الحراري, الصلادة السطحية, خشونة السطح, قوة الالتصاق القصي لطقم الأسنان وقابلية إمتصاص الماء. تم تقسيم العينات الى مجموعة السيطرة (7 عينات) والمجموعة التجريبية (7 عينات) التي تحتوي على 2% من خليط الألياف المعالجة سطحيا وبطول 4 ملم وقد تم إجراء فحص FTIRللتحقق من وجود مادة silane على سطح الألياف وتم تحليل النتائج بواسطة إختبار t- test للتحليل الاحصائي للبيانات.أظهرت النتائج زيادة معنوية في قوة الصدمة, قوة المستعرضة, قوة الإلتصاق القصي لقاعدة الطقم, الصلادة والتوصيل الحراري لمادة راتنج الأكريلك الحراري المدعم بالألياف كما أظهرت النتائج إنخفاض غير معنوي في خشونة السطح وخاصية إمتصاص الماء عند المقارنة مع مجموعة السيطرة. نستنتج من هذه الدراسة أن إضافة خليط من ألياف البولي بروبيلين وألياف السواك المعالجة سطحيا يؤدي الى تحسين الخصائص الفيزيائية والميكانيكية لمادة راتنج الأكريلك.


Article
Miscibility improvement of LDPE/PVA blends by using silane-coupling agent

Authors: Zuhair Jabbar Abdul Ameer --- Nabeel Hasan Hameed
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2018 Volume: 26 Issue: 3 Pages: 98-109
Publisher: Babylon University جامعة بابل

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Abstract

Mixing two polymers usually results in an immiscible system, characterized by a coarse, easy to alter morphology, and poor adhesion between the phases. These blends have large size domains of dispersed phase and poor adhesion between them. Therefore, miscibility of polymer blend must be improved by using suitable additives such as compatibilizer. In this study 5% of silane 3-(trimethoxysilyl)propyl methacrylate is used as compatibilizer to improve the miscibility and compatibility of LDPE/PVA blends. The samples were prepared by using a twin screw extruder. LDPE and PVA have been mixed with different weight proportion. Several tests were carried out to identify the compatibility and miscibility of the blends such as tensile properties, hardness, density, Fourier transforms infrared FTIR, digital microscope, scanning electron microscopy SEM and differential scanning calorimetry DSC. Result show that tensile strength, young modulus, elongation at break, density and hardness is increased with silane addition to the blends. SEM and digital microscope shows an improvement in the miscibility due to the better interaction between the two polymers as silane is added.

خلط اثنين من البوليمرات عادة ما ينتج خليط بوليمري غير ممتزج، يتميز بالخشونة، سهولة تغير الشكل وضعف الترابط بين الطورين. إضافة الى كبر حجم الطور المشتت كبير وضعيف الارتباط بالطور الاخر. لذا فان الامتزاجية للبوليمرات يجب ان يتم تحسينها باستخدام مضافات مناسبة مثل محسن التوافقية. في هذه الدراسة تم استخدام السيلان كمحسن للتوافقية والامتزاجية بين البولي اثيلين واطئ الكثافة و بولي فنيل الكحول. تم تحضير العينات باستخدام الباثق ثنائي اللولب حيث تم خلط نسب مختلفة من البولي اثيلين و بولي فنيل الكحول وبإضافة %5 من مادة السيلان. عدة اختبارات أجريت لتحديد تأثير محسن التوافق على خصائص هذه الخلائط وامتزاجيتها مثل اختبار الشد والصلادة والكثافة والاشعة تحت الحمراء والتحليل الحراري التفاضلي و الفحص بالمجهر الالكتروني الماسح والمجهر الرقمي و أظهرت النتائج زيادة متانة الشد ومعامل يونك، الاستطالة عند القطع والصلادة والكثافة بإضافة السيلان اما نتائج المجهر الالكتروني الماسح والمجهر الرقمي فقد أظهرت حدوث تحسن في امتزاجية البوليمرين.

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