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Article
An Evaluation of the Effect of Bleaching Agent on Microhardness of a New Silorane-Based Restorative System and Methacrylate-Based Restorative Material

Authors: Shatha Abdul Kareem --- Rasha Hameid Jehad
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2012 Volume: 20 Issue: 1 Pages: 385-363
Publisher: Babylon University جامعة بابل

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Abstract

Background: The high reactivity of hydrogen peroxide used in bleaching agents have raised important questions on their potential adverse effects on physical properties of restorative materials. The purpose of this in vitro study was to evaluate the effect of in-office bleaching agents on the microhardness of a new Silorane-based restorative material in comparison to methacrylate-based restorative material.Materials and method: Forty specimens of Filtek™ P90 (3M ESPE,USA) and Filtek™ Supreme XT (3M ESPE, USA) of (8mm diameter and 3m height) were prepared. All specimens were polished with Sof-Lex disks (3M ESPE, USA). All samples were rinsed and stored in incubator 37˚C for 24 hours in DDW. Ten sample of each material were subjected to 37.5% hydrogen peroxide gel (Pola office +, SDI)for 8 minutes while exposed to light curing device, this step was repeated three times for 3 weeks. While the other ten samples for each material was served as control. All specimens were subjected to microhardness test using digital microhardness tester to determine the VHN (Vickers Hardness Number)Results : The Filtek™ P90 exhibited higher microhardness value than Filtek™ Supreme XT. After hydrogen peroxide treatment, both types of composites exhibited low microhardness values but still Filtek™ P90 is harder than Filtek™ Supreme XT.Conclusion : In-office hydrogen peroxide bleaching agent resulted in reduction in microhardness values for both composite materials. Silorane- based composite is more affected by the bleaching agent than methacrylate-based composite.


Article
Effect of Laser Surface Treatment on Wear Resistance of 100Cr6 Steel
تأثير المعاملة الحرارية السطحية بالليزرِ على مقاومة البلى للفولاذ 100Cr6

Author: Khansaa Dawood Salman
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2009 Volume: 27 Issue: 6 Pages: 1151-1161
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The effect of laser surface heat treatment on wear resistance of 100Cr6 steel wasinvestigated. In this work, 100Cr6 steel which is widely used in many industrial of automobileshardened by using Nd: glass laser (l=1.060mm, t=300ms). Three different laser energies have beenused to perform hardening (0.3, 0.58 and 0.93 Joule). A pin-on-disc technique has been used toevaluate wear rate of the specimens as-received and specimens treated by Nd: glass laser atdifferent applied loads and different sliding speeds with 420 r.p.m and 45 HRC of rotatingdisc. The results show that the wear rate increases with increasing applied load and decreases withincreasing sliding speed, wear rate for laser energy 0.93 J less than another energies 0.3 and 0.5 J.Also the microhardness decreases with increasing in depth of hardening, and the microhardnessfor laser energy 0.93 J more than another energies for the same depth.

الخلاصة100 . في هذا البحث تم Cr تمت دراسة تأثير المعاملة الحرارية السطحية بالليزر على مقاومة البلى للفولاذ 6100 والذي يستخدم بشكل واسع في العديد من وسائط النقل والذي تم تصليده باستخدام ليزر Cr استخدام الفولاذ 6نوع نيديوم- زجاج (ذو طول موجي 1.060 مايكرون وطول نبضة 300 مايكرو ثانية). في هذه الدراسة تم0.3 ) جول. استخدمت تقنية المسار على , 0.58, استخدام ثلاث طاقات ليزرية للحصول على التصليد ( 0.93القرص لتحديد معدل البلى للعينات قبل وبعد المعاملة بواسطة الليزر نيديميوم- زجاج عند تسليط أحمال مختلفة45 ). وقد أظهرت النتائج إن معدل البلى يزداد مع زيادة HRC) وسرع انزلاق مختلفة وصلادة القرص الدوار0.93 ) اقل مما هو عليه للطاقات J) الحمل المسلط ويقل مع زيادة سرعة الانزلاق، وان معدل البلى عند طاقة ليزر0.3 ). وكذلك الصلادة المايكروية تقل مع زيادة عمق التصليد، وان الصلادة الدقيقة لطاقة and 0.58 J) الأخرى0.93 ) اكثر من بقية الطاقات ولنفس عمق التصليد. J) الليزر


Article
The Effect of Different Light Cure Systems on Microhardness of Bulk Fill Composite Materials

Authors: Linz A. Shalan --- Samer Awn Thiab
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2017 Volume: 29 Issue: 2 Pages: 13-20
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The aim of this study was to evaluate the effect of three types of light curing devices QTH, LED andFlashmax on the surface microhardness of three types of bulkfill composite resins; Filtek Bulkfill posterior composite( 3M), Tetric Evo Ceram ( Ivoclar Vivadent) and Sonicfill composite ( Kerr)Materials and methods: Total number of 90 samples was prepared, 30 samples for each type of bulkfill composite,were divided into three main groups, group A: Filtek posterior bulkfil (3M), group B: Tetric Evo Ceram (IvoclarVivadent) and group C: contain Sonicfill composite (kerr). Which then divided into three subgroups (n= 10) (1)Samples cured by QTH system (2) Samples cured by LED system and (3) samples cured by Flashmax system then allsamples were subjected for microhardness test (by Vickers hardness tester). The data were recorded and statisticallyanalyzed, by the ANOVA and the Tukey test.Results: the data was subjected to statistical analysis using one way ANOVA and Tukey test, the result revealed thatthere was a high significant difference among the tested units with LED had high VHN values followed by QTH whileFlashmax had lowest VHN values, also there was high significant difference among the tested materials in whichSonicfill composite had higher VHN value followed by Tetric EvoCeram while Filtek bulkfill posterior composite hadthe lowest VHN.Conclusions: microhardness of the composite resin materials depend upon energy of the curing device, time ofexposure, composition of the composite material


Article
Study The Effect of Co Concentration In Nico Thin Films on Some Structure And Mechanical Properties

Author: Alaa A. Abdul-Hamead
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2010 Volume: 28 Issue: 12 Pages: 2486-2496
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Electroplating process has been used to prepare Magnetic NiCo alloys thinfilm with thickness of 1μm on brass alloy substrate using different Coconcentrations .Surface morphology, XRD, atomic absorption, apparent density,open porosity, stresses and microhardness of pure and alloys thin film has beeninvestigated. Results indicated that the pure and alloy of thin films waspolycrstaline with (111) domain orientation changed to (101) with increment Codeposited percentage, which is spontaneously increase with Co molarity increasedin the deposition solution.Microstructure for thin films change from nodularstructure to pyramidal and dendritic structure with changing Co content in film.Apparent density for prepared thin films was less than theoretical density about(8g/cm3), and varying with actual Co deposited content. Open porosity alsoreduced in general with increment of Co content. Mechanical properties showsalteration in internal stress behavior of deposited thin films from compressivestress to tensile stress at (0.05M) of Co. Microhadness also increased withincreasing in the Co percentage in deposited thin films,to about(467Kg/mm2).

مغناطيسية و NiCo استخدمت طريقة الترسيب الكهربائي لتحضير اغشية سبائكية منعلى قواعد لسبيكة من البراص .تم فحص التصوير Co 1 وبنسب مختلفة من μm بسمكالمجهري و حيود الاشعة السينية و التحليل الكيمياوي و الكثافة الظاهرية والمسامية المفتوحة والاجهادات الداخلية و الصلادة الدقيقة للاغشية المرسبة النقية و السبائكية .بينت النتائج ب أنالاغشية المترسبة النقية و السبائكية متعددة التبلور و بالاتجاهية ( 111 ) ويتحول الى ( 101 ) معزيادة نسبة الكوبلت المترسبة و التي تزداد تلقائيا مع زيادة المولارية المضافة الى محلولالترسيب. وتغيرشكل البنية الدقيقة لسطح الغشاء الرقيق من عقدية ناعمة الى شجيرية وهرميةتقريبا مع تغير نسبة الكوبلت بالغش اء .وكان ت الكثاف ة العملی ة للاغش یة المحض رة اق ل م ن الكثاف ة8) وتغی رت م ع تغی ر نس بة الكوبل ت المترس بة فعلی ا .ایض ا انخفض ت g/cm النظری ة ح والي ( 3المسامیة المفتوحة على العموم مع زیادة نسبة الكوبلت.الخواص المیكانیكیة للاغشة بینت تغیر في سلوك الاجهادات الداخلية في الاغشية الرقيقة المترسبة من ضغطية الى شدية عند (0.05M of Co) كذلك ازدادت قيمة الصلادة الدقيقة لهذه الاغشية مع زيادة نسبة الكوبلت بالاغشية الرقيقة.(467Kg/mm المرسبة,وصلت الى حوالي( 2


Article
Effect of Zamzam Water on the Microhardness of Initial Carious Lesion of Permanent Teeth Ename(An in vitro study)l

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Abstract

Chemical tests concluded that Zamzam water is absolutely good and suitable for drinking as it has very high percentage of sodium, calcium, magnesium, and many other minerals. The purpose of this study was to test the effect of Zamzam water on the microhardness of permanent teeth enamel.Teeth samples (n= 30) with artificially initiated carious lesions were divided randomly into three groups, study group treated with Zamzam water (n= 10), control positive treated with sodium fluoride (n=10), and control negative treated with deionized water (n=10). Teeth were subjected for microhardness assessment before and after pH cycling and treatment with the three agents.The microhardness of enamel surfaces treated with Zamzam water is shown statistically significant increase in the values following demineralization which was not different from that of sodium fluoride.Zamzam water cause an increase in the microhardness of the enamel surface after pH-cycling.


Article
Assessment of diametral tensile strength and microhardness of Glass ionomer reinforced by different amounts of Hydroxyapatite

Authors: Mohammed Rasheed محمد رشيد --- Raghad A. Mohammed رغد محمد
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2006 Volume: 18 Issue: 3 Pages: 17-20
Publisher: Baghdad University جامعة بغداد

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Abstract

Back ground: Glass ionomer materials lack resistance to wear and pressure and are susceptible to moisture during the initial stages of setting and dehydration. So this study was done to assess diametral tensile strength and microhardness of glass ionomer reinforced by different amounts of hydroxyapatite.Materials and methods: In this study a hydroxyapatite material was added to glass monomer cement at different ratios: 10%, 15%, 20%, 25% and 30% (by weight). The diametral tensile strength test described by the British standard specification for zinc polycarboxylate cement was used in this study and the microhardness test was performed using Vickers microhardness testing machine and the microhardness values were calculated and statistical comparison was performed on the tested groups.Results: The group of glass ionomer cement that contains 20% hydroxyapatite has higher diametral tensile strength and microhardness values than other groups of this study. Also the results showed that the group of glass ionomer cement without hydroxyapatite has the lowest values of diametral tensile strength and microhardness than other groups. The groups of glass ionomer cement with 10%, 15%, 25% and 30% hydroxyapatites also showed increasing in diametral tensile strength and microhardness values in comparison with group of glass ionomer cement without hydroxyapatite.Conclusion: The addition of hydroxyapatite to conventional glass ionomer cement will increase its diametral tensile strengthand microhardness.


Article
Effect of Siwak Extract on the Microhardness and Microscopic Feature of Initial Caries-Like Lesion of Permanent Teeth, Compared to Fluoridated Agents

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Siwak is a chewing stick used to clean the teeth and message the gum. Their routine use was shown to be associated with the reduction in severity of dental caries. This study aimed to test the effect of water Siwak extract on the microhardness and microscopic features of artificially initiated carious lesion of the outer enamel surface, in comparison to stannous fluoride and sodium fluoride. Upper first premolars were extracted and subjected to pH cycling procedure. Teeth immerged individually in 20 ml of selected agents for four minutes then rinsed by de ionized water. Agents involved were 5% and 10% water Siwak extract, 8% stannous fluoride and 0.05% sodium fluoride. Samples were subjected to Vickers microhardness test and microscopic examination before and after the pH cycling and following insertion in the agents. Water Siwak extract, stannous fluoride and sodium fluoride were found to increase the microhardness values of de mineralized enamel surfaces, this were statistically highly significant for Siwak extract and stannous fluoride (P< 0.01) and significant for sodium fluoride. However none of the mentioned agents was able to increase the micro hardness to approximate the original values of the sound enamel. Under polarized light results revealed that water Siwak extracts and stannous fluoride produce the best remineralization surface zone. Water Siwak extracts is very effective in remineralization of initial carious lesion.


Article
An in- vitro evaluation the effect of endodontic irrigation solutions on the microhardness of root canal dentin. Prof.

Authors: Dr. Itab Nasser Hussein د. عتاب ناصر --- Dr. Abdul Karim AL-azzawi د. عبد الكريم العزاوي
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2011 Volume: 8 Issue: 1 Pages: 19-23
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The aim of this study was to evaluate the effect of 5.25 sodium hypochlorite and17%EDTA on the microhardness of root canal dentin .Fifteen, maxillary incisor teeth extracted for periodontal reasons were used. Thecrowns of the teeth were removed at the CEJ. The roots were separated longitudinallyinto two segments, embedded in acrylic resin, and polished. A total of 30specimenswere divided into 3 groups of 10 teeth at random according to the irrigation solutionused: group 1: 5.25% NaOCl for 1min; group 2: 17% EDTA for 1 min; and group 3:distilled water (control). Each group was submitted to Vickers microhardnessindentation tests. The data were recorded as Vickers numbers and the results wereanalyzed statistically by using one-way ANOVA.The results showed that, irrigation with either sodium hypochlorite or EDTAdecreased the microhardness value of root dentin. Irrigation with EDTA gave morereduction of dentin compared to sodium hypochlorite. The reduction of VHN ofdentin following the irrigation treatment was statistically significant (p< 0.05 ) .Both sodium hypochlorite and EDTA irrigation solution significantly reduced themicrohardness of root dentin.


Article
The effect of drinking yogurt on the microhardness of posterior composites resin

Author: Dr. Saif Alarab A. Mohmmed,B.D.S.,M.Sc.
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2011 Volume: 8 Issue: 2 Pages: 93-99
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Background :This study was conducted to evaluate the effect of yogurt on thesurface microhardness of two types of composite resins; (Filtek™ P90 Low ShrinkPosterior Restorative, 3M ESPE,USA), and (Filtek™ Z350 Posterior Restorative, 3MESPE,USA).Forty samples of composite were prepared by using cylindrical mold (2mm inhight and 8mm in diameter )..All specimens were stored in plastic container thatcontain distilled water and incubated 37cº for 24 hours before they were tested. twentysamples of each type of composite were divided into two groups (10) for each ,baseline measurements for surface microhardness test was taken for all compositesamples using the micromet microhardness tester (Vichers hardness tester) with al00g load was applied for 15 seconds in which three indentations were made for eachsample and converted into Vickers Hardness Number (VHN ) .After baselinemeasurement 10 samples of each type of composite were alternately immersedmanually by holding the specimen by a pair of tweezers from its sides, , in drinkingyogurt (Activia ,KSA) and artificial saliva for 10 cycles 5 seconds each at roomtemperature (25cº). This was repeated three times a day (8am,4pm,12am) at 8hoursintervals for one week. the other 10 samples for each type of composite wereimmersed in artificial saliva only. The total soaking time in both drinking yogurt andsaliva was 100 seconds. After the soaking sequence was completed the specimen wasrinsed with distilled water and subjected to surface microhardness test (Vichershardness tester).Descriptive statistics(mean values and standard deviations with the minimum andmaximum values and Statistical analysis of data by using student t - test for all groupswas carried out between the means of each type of composites ,the results showed asignificant reduction in VHN values (at P<0.05)of Filtek™ Z350 PosteriorRestorative composites after immersion in artificial saliva, while the (Filtek™ Z350Posterior Restorative, 3M ESPE) composite showed a highly significant reduction inVHN values (at P<0.01)after immersion in drinking yogurt. Filtek™ P90 Low ShrinkPosterior Restorative composites showed a non significant reduction in VHN values(at P>0.05) after immersion in artificial saliva and after immersion in drinking yogurt.Filtek™ P90 Low Shrink Posterior Restorative composites have highest VHNvalue than Filtek™ Z350 Posterior Restorative composites, and surface microhardnessresults showed that drinking yogurt highly significantly effect on the Filtek™ Z350Posterior Restorative composites while it has non significant effect on the Filtek™P90 Low Shrink Posterior Restorative composite


Article
Evaluation of Chemo-mechanical Caries Removal (CarisolvTM Gel) on Primary Teeth: A Microhardness Study

Author: Baydaa A Al-Rawi
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2012 Volume: 12 Issue: 20 Pages: 289-294
Publisher: Mosul University جامعة الموصل

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Abstract

the purpose of this study was to compare the Vickers hardness of sound dentin after carious tissue removal using the chemo–mechanical method and the conventional rotary method. Materials and Methods: The carious dentin of thirty extracted human primary lower second molars was removed using Carisolv™ and conventional rotary methods. The Vickers hardness number (VHN) of the cavity floor was determined and the adjacent sound dentin of each tooth was used as a control reference. Results: The results indicated no statistical difference in the microhardness of the dentin in the cavity floor after treatment with Carisolv™ gel and conventional rotary method and no statistical difference in the microhardness of the dentin of both types of caries removal compared with the adjacent control areas. Conclusions: The Carisolv™ gel does not cause a significant change in the microhardness of dentin that remains after being submitted to carious tissue removal.

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