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Article
Evaluation of some physical properties of the copolymerized temporary crown and bridge auto–cured acrylic resin (Reinforcement)

Authors: Akram A Mohammad --- Nadiaa H Hasan --- Lamia T Rejab
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 10 Pages: 160-165
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To evaluate some of the physical properties which are transverse strength, tensile strength,surface hardness, water sorption and solubility of the auto–cured acrylic resin when copolymerizedwith epoxy resin at two different ratios 10% and 20% of its weight and then compared with that ofauto–cured alone and heat–cured acrylic resin alone. materials and methods: The tested samples weredivided into four groups according to the materials to be used and the samples of each group weresubdivided according to the test to be done. The samples were prepared according to ADASpecification No. 12. Statistically analysis of the physical properties was with (ANOVA) and Duncan'smultiple range test to determine significant different at (p ≤ 0.05 ) level of significance, and the meanvalue of the water sorption and solubility ratios compared with accepted limit of ADA SpecificationNo. 12. Results: The transverse strength, tensile strength and surface hardness in this study showed thatthere was a highly significant difference between the four tested groups. The result appeared improvingof the mechanical properties and decreasing the ratio of water sorption and solubility of the auto–curedacrylic resin and the resin was reinforced when copolymerized at 10%, but the values still not reachedthat of the heat–cured acrylic resin and they became worse when copolymerized at 20%.


Article
Effect of Nanocomposites TiO2 addition on the Dielectric Properties of Epoxy resin
تأثير متراكبات النانو بإضافة TiO2¬ على خواص العزل لراتنج الأيبوكسي

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Abstract

Sheets of Epoxy (EP) resin with addition of TiO2 of grain size (1.5μm, and 50nm) and weight percentage (1%, 3%, and 5%) were prepared. Discs of 20mm diameter and 3mm thickness were cut for dielectric measurements. Dielectric properties (dielectric constant, dispassion factor and electrical conductivity) over the frequency range 102 -106 Hz were measured.Comparison was made between the effect of micro and nano particles of TiO2 on the dielectric properties of EP composites with different weight percentage. Epoxy composites with micro sized particles of TiO2 were observed to have the better values of dielectric properties.

في هذا البحث تم تحضير صفائح راتنج الايبوكسي Ep باضافة ثنائي اوكسيد التيتانيوم TiO2 بمقاس حبيبي ((1.5μm, 50nm وبنسب وزنية مئوية مختلفة (1%, 3%, 5%). تم قطع اقراص بقطر 20mm وسمك 3mm من المادة المحضرة ولذلك لغرض القياسات العزلية. الخواص العزلية (ثابت العزل وعامل الفقد والتوصيلية الكهربائية) اجرت القياسات لمدى من الترددات بين 102 -106 Hz.تم كذلك مقارنة تأثير الجسيمات TiO2 من ابعاد النانومتر والمايكرمتر على الخصائص العزلية من متراكبات الايبوكسي وبنسب وزنية مختلفة. وتبين من النتائج ان الجسيمات TiO2 بابعاد المايكرو متر ذات خصائص عزلية افضل


Article
The effect of addition chlorhixidine gluconate (powder) on the properties of heat cured acrylic resin

Authors: Alia'a W. Alomari --- Nada Z. Mohammed --- Amer A Taqa
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2011 Volume: 11 Issue: SpIss Pages: S25-S34
Publisher: Mosul University جامعة الموصل

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Abstract

Aims of the Study: The current study aims to evaluate the effect of the addition of chlorohexidine gluconate (CHX) (powder) on some physical , mechanical properties and antimicrobial effect. Materials and Methods: In this study two hundred and forty samples of heat cured acrylic resin (Major base-2) were prepared and divided into: control group( without the addition of CHX) and experimental groups(with the addition of CHX(powder) at (1%, 2%, 3%)) to evaluate transverse strength, tensile strength, , surface hardness, dimensional accuracy, deflection , residual monomer in addition to antimicrobial effect for heat cured acrylic resin before and after the addition of CHX(powder). Results: Results showed a statistically significant difference at (p0.05) between control and experimental groups. The addition of CHX (powder) into heat cured acrylic resin increases its flexibility in addition to it's antimicrobial effect. Group of 1% CHX has the highest value of transverse strength, tensile strength ,surface hardness and dimensional accuracy after control group. Conclusions: In addition to its antimicrobial effect, CHX increases the flexibility of heat cured acrylic resin. As the concentration of added CHX increased, the flexibility of heat cured acrylic resin specimens will be increased

Keywords

CHX --- acrylic resin --- flexibility


Article
Effect of triammonium orthophosphate on fire retardationof Epoxy resin reinforced with wood flour
تأثير ثلاثي أمونيوم أورثو فوسفات على مقاومة الاحتراق لراتنج الايبوكسي المسلح بنشارة الخشب

Authors: Mohammed. H. Mokhilif محمد هلول مخيلف --- Harith. I. Jaffer حارث ابراهيم جعفر
Journal: Baghdad Science Journal مجلة بغداد للعلوم ISSN: 20788665 24117986 Year: 2011 Volume: 8 Issue: 2عدد خاص بمؤتمر الفيزياء Pages: 671-675
Publisher: Baghdad University جامعة بغداد

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Abstract

Epoxy resin reinforced by 30% of wood flour was prepared as a composite . Triammonium orthophosphate as a flame retardant was added to composite at weight percentages of ( 0 , 2 , 3 , 5 , 7 , and 10 ) % . Hand lay-up technique was used to prepare sheets from that composite. The results indicated that the rate of burning decreases with increasing the weight percentage of that flame retardant. And the limiting oxygen Index (LOI ) increases with increasing concentration of that flame retardant .

تم دراسة تأثير اضافة ثلاثي أمونيوم اورثو فوسفات على لهوبية راتنج الايبوكسي المسلح بـ 30% من نشارة الخشب . استخدم المضاف بنسب مئوية ( 0 , 2 , 3 , 5 , 7 , 10 ) % . ثم حضر صفائح من المتراكب بالطريقة اليدوية لصب مكبوسات . قد اظهرت النتائج ان معدل احتراق العينات يتناقض مع زيادة النسب المئوية للمضاف وان معامل الاوكسجين المحدد (LOI ) يزداد مع زيادة تركيز المضاف .


Article
ROOT REINFORCEMENT USING CAST POST CEMENTED WITH DIFFERENT TYPES OF CEMENTS

Authors: Mohammed F. Moutlak B.D.S.,M.Sc * * د. محمد مطلق --- Fareed Ghiab Nu'man B.D.S.,M.Sc * د. فريد غايب النعيمي
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2006 Volume: 3 Issue: 2 Pages: 122-126
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The purpose of this in-vitro study is to evaluate and compare the fractureresistance of endodontically treated teeth restored using cast posts cemented withdifferent types of cement. Thirty intact human maxillary central incisors were selectedfor this study. The crowns were removed and endodontic therapy were done on theroots, which were then prepared to receive cast posts, after their fabrication, the castposts were cemented with zinc phosphate cement (group I), resin modified glassionomer cement (group II),and resin cement (group III). The samples were subjectedto compressive fracturing loads by a Zwick testing machine at a cross head speed of5mm/min., with an angle of 45º to the long axis of the tooth. The results showed thatthe posts cemented with resin cement exhibited the highest mean failure load followedby posts cemented with resin modified glass ionomer cement , while posts cementedwith zinc phosphate cement exhibited the lowest mean failure load.


Article
Effect of using two packing Technic on Hardness of two dental acrylic resin

Author: Najim O. Nasser
Journal: nursing national Iraqi specility المجلة العراقية الوطنية للعلوم التمريضية ISSN: 18122388 Year: 2012 Volume: 25 Issue: 1 Pages: 12-18
Publisher: Baghdad University جامعة بغداد

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Abstract

Objective: the aim of this study is to invest age and determine the effect of using (2) packing technique (conventional and new tension technique) on hardness of (2) types of heat cure acrylic resin which are (Ivoclar and Qual dental type). Methodology : this study was intended the using of two types of heat cure acrylic (IVoclar and Qual dental type) which are used in construction of complete denture which packed in two different packing technique (conventional and new tension technique) and accomplished by using a total of (40) specimens in diameter of ( 2mm thickness, 2 cm length and 1 cm width) . This specimens were sectioned and subdivide into (4) group each (10) specimens for one group , then signed as (A, Al B , B 1) according to the method of technique and type of acrylic that used . The hardness of the specimens were measured by shore hardness test in technology university, Baghdad. Results: this study revealed that the type of acrylic which packed by new tension technic had less effect by hardness in compared with conventional packing technic, the result also showed that the type of acrylic resin have a little effect on hardness of the two types, and also it show highly mean value of hardness was indicate in Qual dental type in conventional technique, while the least mean value of hardness showed in Ivoclar type in new tension technique. Recommendations : this study has been conducted as a preliminary for future studies to give a sit of about the effect of hardness on other types of commercial heat acrylic resin that used in construction of prosthodontics restoration and dented prosthesis, it necessary to evaluate the hardness of any material used in construction of denture bases , it is suggested to under take a farther studies about using advance technique and better apparatus and device in packing the acrylic material and measured the value of hardness and its effect on this material.

الهدف : تهدف الدراسة الى بيان مدى تأثير طريقتي تعليب ( الطريقة العادية للتعليب ثم طريقة الضغط الجديد ) على نوعين من مادةة الاكريلك الحار المستخدم في صناعة طقوم الأسنان وهما ( الإيفوكلار والكويل دينتل) على صلادة هذين النوعين من المادة . المنهجية : أجريت الدراسة باستخدام نوعين من مادة الاكريلك الحار المستخدم في تصنيع الطقوم نوع (الإيفوكلار) ثم نوع ( الكوايل دينتل) ثم تعليب هذين النوعين بطريقتين مختلفتين ، بالطريقة العادية لتعليب المادة أولاً ثم باستخدام جهاز الضغط الجديد ثانياً . تمت الدراسة باستخدام (40) عينة ونموذج بابعاد (2 ملم سمك ، 2 سم طول ، 1 سم عرض ) للعينة ، وزعت إلى اربع مجاميع بواقع (10) عينات لكل مجموعة ، وزعت المجاميع الاربعة وفق التأشيرات حسب طريقة التعليب المستخدمة ونوع الأركيلك المستخدم والطريقة المستخدمة .تم قياس الصلادة بمقياس شور للصلادة الجامعة التكنولوجية – بغداد . النتائج : اظهرت نتائج الدراسة التي خضعت للتحليل الإحصائي ان مادة الاكريلك المعلبة بنظام الضغط الجديد قليل التأثير على صلادة المادة في الطريقة العادية وأن لا تأثير على نوع الاكريلك المستخدم في الطريقتين كذلك بينت الدراسة ان اعلى قيمة لمتوسط الصلادة ظهرت في الطريقة العادية بينما اقل معدل للصلادة في الطريقة الاخرى كذلك تبين من الدراسة ان اعلى قيمة لمتوسط الصلادة ظهر في نوع ( الكوايل دينتل) في الطريقة العادية في حين معدل الصلادة لنوع (الإيفوكلار) كان بنسبة أقل . التوصيات : هذه الدراسة اعدت لتكون تمهيداً لسلسلة من الدراسات المستقبلية لبيان مدى تأثير الصلادة على أنواع اخرى من مادة الاكريلك التجاري المستخدم في صناعة الاسنان وإيجاد طرق أخرى مستحدثة لتعليب المادة باستخدام تقنيات حديثة. ونقترح تجهيز مختبرات صناعة الاسنان بأجهزة حديثة واستخدام التقنيات العالية في جميع مراحل وخطوات اعمال مادة الاكريلك المستخدمة في صناعة طقوم الاسنان وطرق قياس وتأثير خاصية الصلادة على هذه المادة .


Article
The Effect of Two Types of Separating Medium and Investment Materials on Some Physical Properties of Acrylic and Nylon Denture Base Materials

Authors: Suad Jafar Alnakash --- Nagham Bahjat Kamil --- Farah Nabeel Mohammed Tahir Al-Khayyat
Journal: Karbala Journal of Medicine مجلة كربلاء الطبية ISSN: 19905483 Year: 2013 Volume: 6 Issue: 2 Pages: 1675-1683
Publisher: Kerbala University جامعة كربلاء

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Abstract

background: The relatively rough surface of gypsum mould may be penetrated byacrylic denture base resin and adhere to it, to prevent this, a separating medium mustbe employed.Objectives: The aim of this study is to evaluate the effect of separating medium substituteand investment materials on Surface roughness, Water sorption and solubility of acrylic andnylon denture base materials.Material and method: Two types of separating medium were chosen (Cold mold seal andglycerin). 160 specimens were prepared from heat cure and Valplast resins. Each main groupwas subdivided into four subdivisions according to the type of investment material andseparating medium used; each group of them contains 10 specimens for each test.After processing of both resins, some physical properties such as water sorption, solubilityand surface roughness have been evaluated according to investment material and comparedwith those processed using cold mold seal and glycerin.Result: In this study, the surface roughness and water solubility of both base materials aresignificantly higher when using cold mold seal than glycerin. Mean value of heat-cure acrylicresin shows high water sorption than that of Valplast. When compared by ANOVA test, thereis no significant difference between groups in both investment materials.Conclusion: The use of glycerin as a separating medium leads to smoother surfaces of bothdenture base materials, while for water sorption, neither the separating medium nor theinvestment material has an effect on it. Cold mold seal leads to higher water solubility of bothbase materials regardless of the type of investment material.


Article
The effect of indirect veneering materials as light interpose on microhardness of dual cured resin cements

Authors: Maha A AL-Murad --- Ma’an M Nayif
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 22 Pages: 290-295
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The aim of this study was to investigate the influence of different indirect veneering materials on the microhardness of dual-cured resin cements. Materials and Methods: Three disc specimens (2.0 mm height and 5mm diameter)were prepared from the following indirect restorative materials (Indirect composite resin, Gardia-GC, JAPAN, Feldspathic porcelain VITA VIMK 95-Germany and Zirconia veneer, VITA-Zahnfabrik, Germany). Two dual cure resin cements were used ( Variolink II, Ivoclar Vivadent AG, Liechtenstein and Bis-Cem, Bisco-Schaumburg, USA). Twenty specimens were prepared from each type of cement and divided into 4 groups, one as control and others as indirect restorative materials. After mixing cements were placed in a plastic mold (5mm diameter and 1mm height ) and light activated directly or through veneering discs for 30s using LED light at 500mW/cm2. Specimen subjected to three indentation using Vicker hardness tester with load of 50gm for 15 second. Data were statistically analyzed using ANOVA and independent t-test at (α= 0.05). Results: For both cements the control groups showed higher hardness value than other groups. Specimens cured through indirect resin composite shows the highest microhardness while those cured through Zirconia shows the lowest value. Variolink II resin cement demonstrated higher microhardness than Bis-Cem cement regardless of the curing condition. Conclusions: Type of indirect restorative veneering materials influence microhardness of resin cement luting agent.


Article
Fatigue Behavior Of Chopped Carbon Fiber Reinforced Epoxy Composites
سلوك الكلل لمتراكب الايبوكسي المدعم بألياف الكاربون المقطعة

Authors: Ekram .A.AL-Ajaj أكرام عطا العجاج --- Mohammed Hussein B. Hassan محمد حسين بشار
Journal: Iraqi Journal of Physics المجلة العراقية للفيزياء ISSN: 20704003 Year: 2010 Volume: 8 Issue: 11 Pages: 110-117
Publisher: Baghdad University جامعة بغداد

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Abstract

Hand-lay up method was used to prepare the samples made of epoxy (EP) as a matrix reinforced with chopped carbon fibers (CCF). The fatigue behavior of epoxy resin /chopped carbon fiber composites was studied with different weight percentage of chopped carbon fibers (2.5%,5%,7.5%,10%,12.5%). The fatigue test was carried out under alternate bending method, which was made by applying sinusoidal wave with constant displacement (15mm), stress ratio R=-1,and loading frequency 10Hz, which is believed to give a negligible temperature rise during the test. The results of the maximum stress, fatigue strength, fatigue limit and fatigue life of the tested composites are calculated from stress(S)-number of cycles(N) (S-N) curves.
It was shown that increasing weight percentage of chopped carbon fibers increase the values of maximum stress for all composites, while the values of fatigue strength, fatigue limit and fatigue life increasing for all composites except the composite with reinforcing weight 12.5%, which was subjected to rapid failure (fracture). This failure could be due to the debonding of the chopped carbon fibers from the matrix epoxy.

حضرت العينات للفحص بطريقة التشكيل اليدوي من مادة الايبوكسي كمادة أساس ودعمت بألياف الكاربون المقطعة ( chopped carbon fiber(CCF.تمت دراسة سلوك الكلل لمادة الايبوكسي ومتراكباتها المدعمة بأليـاف الكـاربون المقطعة وبنسب وزنية مختلفة هي 10%, 7.5%, 5%, 2.5% و%12.5 بطريقة الثني المتناوب. أجري فحص الكلل بطريقة الثني المتناوب وبتسليط حمل جيبي بإزاحة بقيمة ثابتة مقدارها 15mm وبنسبة أجهاد R=-1 وبتردد 10Hzوالتي يعتقد بأنها تمنع أي زيادة في درجة الحرارة. وتم حساب أعظم جهد, مقاومة الكلل, حد الكلل وعمر الكلل لكل المتراكبات من منحنيات الإجهادS)) مع عدد الدورات N)) وأظهرت نتائج الفحص تأثير زيادة نسبة التدعيم على سلوك الكلل للعينات وذالك بزيادة قيمة أعظم جهد لجميع المتراكبات وكذلك بزيادة قيم مقاومة الكلل,حد الكلل وعمر الكلل لجميع العينات باستثناء العينة ذات النسبة الوزنية 12.5% والتي تتعرض للفشل السريع(الكسر) ويحدث الكسر بسبب عدم الترابط القوي بين ألياف الكاربون ومادة الأساس الايبوكسي.


Article
Porosity of different thickness of acrylic polymerized by different methods.

Author: Luay N Abood
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 10 Pages: 173-179
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To evaluate the porosity that occur in the acrylic resin denture base polymerized by themicrowave cycle and conventional water bath with two different thickness, relation between thethickness of specimen and its percentage of porosity. Material and methods: Forty rectangular resinspecimens with the following dimensions (65×40×6mm), (65×40×3mm) were subdivided according topolymerization method into microwave cycle and conventional heat polymerization method to obtain10 specimens with different polymerization method and thickness, for each one of 4 groups. Porositywas calculated by measure the specimen volume before and after its immersion in water, data wereanalyzed by student t–test analysis at ( p< 0.05). Results: Showed that specimens of (6mm) that curedby microwave polymerization method showed significantly higher percentage of porosity whencompared to the same thickness of conventional water bath polymerized acrylic resin at (p<0.05), whileno significant difference between the percentage porosity of the conventional and microwave heatcured acrylic resin of (3mm) thickness specimens. Also there is no significant difference between thethickness of specimen and the conventional water bath method of heat cured acrylic resin. While formicrowave curing method of heat cured acrylic resin there is significant difference for increase ofpercentage of porosity with increase of thickness of specimens. Conclusions: The conventional acrylicresin of (≥3mm) specimens thickness can be polymerized with microwave curing method safely withless porosity , while for (≥ 6mm) specimens thickness is preferred to be polymerized by conventionalwater bath curing method

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