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Article
The shear bond strength of an immediate and delay repaired light-cure composite restoration (In vitro study)

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Abstract

Background: Defects in composite resin restoration whether discovered at the time of placement or associated withold composite resin restoration could be repaired without replacing the entire restoration. This in vitro study wasconducted to determine and compare the shear bond strength of an immediate and delay repaired light curedcomposite restoration.Materials and methods: Eighty acrylic blocks (25x25x15 mm) were constructed from cold cure acrylic resin; each onecontained an acrylic hole (6mm diameter and 3mm depth) that filled with Helioprogress composite resin. The surfacelayer of the composite resin samples was light cured through plastic strip, abraded by finishing discs and rinsed withdeionized distilled water for 15 sec. The eighty specimens were divided randomly into two groups according to thestorage time in deionized distilled water before the repair:Group I: Stored for 15 min. (Immediate repair group)Group II: Stored for 1week. (Delay repair group)Both groups were subdivided into 4 subgroups according to the surface treatment they received:Subgroup 1: No surface treatment (control)Subgroup 2: 37% phosphoric acid etchant (15 sec.)Subgroup 3: Heliobond (light activated for 20 sec.)Subgroup 4: 37% phosphoric acid and Heliobond.Repair was done by using a standardized translucent plastic straw (3mm diameter and 6mm length) and was filledHelioprogress composite resin and light cured for 40 sec. in four directions. All the specimens were stored in deionizeddistilled water for 24 hr. testing was done by the Zwick testing machine by applying shearing force with speciallydesigned chisel-shape rod. Data obtained were statistically analyzed using analysis of variance test and t-test.Results: The results showed very highly significant difference between the similar subgroups in group I vs. group II andthere was non-significant difference between subgroup 1 vs. 2 and between subgroup 3 vs. 4.Conclusion: Delaying the repair procedure for 1 w resulted markedly reduced the bond strength, the surfacetreatment with 37% phosphoric acid slightly reduced the bond strength in the immediate repair while slightlyincreased it in the delay repair, Furthermore, the surface treatment with Heliobond fifth generation bonding agentmarkedly increased the bond strength in both repairs.

Keywords

Repair --- composite --- shear bond


Article
The Effect of Different Disinfectant Solutions on Shear Bond Strength of Acrylic Teeth to Flexible Denture Base Material

Author: Ihssan F Al-Takai
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2014 Volume: 14 Issue: 1 Pages: 145-152
Publisher: Mosul University جامعة الموصل

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Abstract

is to evaluate the effect of three different disinfectant solutions on shear bond strength of artificial acrylic teeth for retention to flexible denture base material at three different periods of time. Materials and Methods: The total number of samples was (60) divided into 4 groups according to the three chemical disinfectant solution which used and the control distilled water group: Group( I) vinegar group, Group( II) salt group , Group(III) Chlorohexidine group , Group (IV ) the control distilled water group, where each group was subdivided into three subgroups according to disinfection periods which are 1week, 1month and 3month where each group contain five samples. The samples of shear bond strength test were consist of acrylic teeth with T-shape design for retention attached to rod of valplast The test was performed using a Universal testing machine. ANOVA, DuncunP,Ps multiple range and Post Hoc Tests were carried out to determine the significant difference at p ≤ 0.01%. Results: The results appeared that control distilled water group has the highest value for the three periods of disinfection (1 week,1month,3months), while vinegar solution group has the least value. The results showed that there were significant differences between the four tested groups and also there were significant differences among all periods of time of disinfections. Conclusion: There was a significant difference of shear bond strength between artificial teeth and flexible denture base material after disinfection in the four disinfectant solutions for all periods of time of immersion. Vinegar group had highest effect on the bond strength while the distilled water group had the least effect after all periods of time of disinfections. Shear bond strength decreased with increasing the time immersion. The shear bond strength was lowest in chloherxidine group as the time of immersion increase when compared with the two other groups of disinfection solutions in this study.


Article
Evaluation of shear bond strength of brackets bonded to fluoride-treated enamel surfaces: An in vitro study

Authors: Ahmad A ABDUL-MAWJOOD --- Khidair A SALMAN
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2001 Volume: 1 Issue: 3 Pages: S343-S352
Publisher: Mosul University جامعة الموصل

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Abstract

Enamel decalcification is a well-recognized problem associated with orthodontic treatment with fixed multibanded appliances. Several methods have been proposed to minimize the incidence and severity of white spot decalcification around brackets. The present study is concerned with the evaluation of the effect of different topical fluoride gels, applied before and after etching on the shear bond strength of directly bonded orthodontic brackets. The sample consisted of (70) human upper first premolars distributed to (7) groups: group A served as a control; groups B1, C1, andDl received, for (4) minutes prior to etching, a topical application of neutral sodium fluoride gel (1.1%), sodium monofluorophosphate gel (1.2%), and acidulated phosphate fluoride gel (1.23%) respectively. Groups B2, C2, and D2, on the other hand, were treated, for (4) minutes after etching, with topical application of neutral sodium fluoride gel (1.1%), sodium monofluorophosphate fluoride gel (1.2%), and acidulated phosphate fluoride gel (1.23%) respectively.The brackets were loaded under shear to failure using Universal Compression Machine Apparatus. The shear strengths were recorded in Megapascals.The results of the present study showed that the application of fluoride gels for (4) minutes before and after etching did not alter the shear bond strengths of directly bonded orthodontic brackets, when compared with the control group, for all groups except for group D2 in which the topical application of acidulated phosphate fluoride gel for (4) minutes after etching has resulted in a significant reduction in shear bond strength and severity of white spot decalcification around brackets.

Keywords

Bond strength --- fluoride


Article
Embedded Length Of Steel Bars In Self Compacted Concrete (SCC)

Authors: Ali I. Salahaldin --- Amer F. Izzat
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2011 Volume: 17 Issue: 5 Pages: 1077-1089
Publisher: Baghdad University جامعة بغداد

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Abstract

Experimental research was carried out on eight reinforced concrete beams to study the embedded length of the longitudinal reinforcement. Six beams were casted using self compacted concrete, and the two other beams were casted using normal concrete. The test was carried out on beams subjected to two point loads. The strain and the slip of the main reinforcement have been measured by using grooves placed during casting the beams at certain places. The measured strain used to calculate the longitudinal stresses (bond stress) surrounding the bar reinforcement, The study was investigated the using of self compacted concrete SCC on the embedded length of reinforcing bars, and comparing the results with normal concrete.The test results show that using SCC improve the concrete properties like the compressive strength and the tensile strength which mainly affected the bond strength and the splitting of the concrete cover failure. The testes show that with increasing concrete strength the bond strength increased.

دراسة عملية اجريت على ثمان عتبات خرسانية مسلحة لدراسة طول الطمر لقضبان حديد التسليح الموضوع في الخرسانة.ست نماذج استخدمت فيها الخرسانة ذاتية الرص ونموذجان استخدم فيهما خرسانة اعتيادية. الفحوصات اجريت على عتبات حملت بنقطتي تحميل. وباستخدام فراغات معينة وضعت في اثناء الصب داخل النماذج لقياس الانفعالات في قضبان حديد التسليح وكذلك لقياس الانزلاق الذي من الممكن ان يحدث, تم قياس اجهاد القص المحيط بقضبان حديد التسليح والمسبب للفشل وانسحاب قضبان حديد التسليح. الدراسة ركزت على عاملين رئيسيين هما:-قوة تحمل الخرسانة.-وطول الطمر المتاح لقضبان حديد التسليح.لايجاد كيفية تاثيرهما على قيم اطوال الطمر في حالة استخدام خرسانة ذاتية الرص. وكذلك مقارنة النتائج مع الخرسانة الاعتيادية. اظهرت النتائج تحسن في خواص الخرسانة في حالة استخدام الخرسانة ذاتية الرص من ناحية مقاومة الانضغاط ومقاومة الشد الذي يؤثر تاثير مباشر على مقاومة الترابط وفشل الغطاء الخرساني وتهشمه


Article
The Effective Embedded Length of Steel Bars in Self Compacted Concrete (SCC)

Authors: Ali I. Salahaldin --- Amer F. Izzat
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2011 Volume: 17 Issue: 3 Pages: 594-609
Publisher: Baghdad University جامعة بغداد

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Abstract

Eight reinforced concrete beams were tested in order to investigate the effective embedded length of the longitudinal reinforcement bar in self compacted concrete (SCC). All specimens were reinforced with a uni-reinforced bar, six of them embedded in self compacted concrete and the others embedded in normal concrete. The test was carried out on simply supported beams loaded at two points. At the end of the reinforcement bar slip was measured, also under the loading point slip and the bar strain were measured. The investigated variables in this study were: The bar diameter, and the available embedded length.To find out how these variables influence the embedded length in case of using self compacted concrete and comparing it with the normal concrete. The results show that, with increasing the bar diameter, bond stress slightly decreases, while with increasing the embedded length of the longitudinal bar the bond stress decreases and this improves the mode of the bond failure, especially for the specimens having small bar diameter

دراسة عملية اجريت على ثمان عتبات خرسانية مسلحة لدراسة الطول المطمور لقضبان حديد التسليح الموضوع في الخرسانة ذاتية الرص . كل التماذج تحتوي على قضيب تسليح احادي . ست منها استعملت فيها خرسانة ذاتية الرص ونموذجين استعمل فيها الخرسانة الاعتيادية. الفحوصات اجريت على عتبات بسيطة الاسناد, حملت بنقطتي تحميل. في نهاية حديد التسليح تم قياس الانسحاب , واسفل نقطة التحميل تم قياس الانسحاب لحديد التسليح مع الانفعال الحاصل في حديد التسليح.تم بحث المتغيرات التالية في هذه الدراسة: قطر قضيب حديد التسليح. وطول التثبيت المتاح لقضبان التسليح.لايجاد كيفية تاثيرهما على قيم الطول المطمور في حالة استخدام خرسانة ذاتية الرص ومقارنتها بالخرسانة الاعتيادية.اظهرت النتائج المختبرية بانه مع ازدياد قطر حديد التسليح يقل اجهاد الترابط بمقدار طفيف. ومع ازدياد الطول المطمور يقل اجهاد الترابط وهذا يحسن من نوع فشل الترابط الحاصل, وخصوصا في النماذج الحاوية على تسليح قليل.


Article
EXPERIMENTAL BOND FORCE-SLIP RELATIONSHIPS FOR EPOXY-COATED REINFORCING BARS UNDER ELEVATED TEMPERATURE CONDITIONS
د ا رسة تجریبیة لعلاقات قوةالربط-الانزلاق لقضبان التسلیح المغطاة بالایبوكسي في درجات الح ا ررة العالیة

Author: Saad Khalaf Mohaisen سعد خلف محیسن
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2012 Volume: 5 Issue: 1 Pages: 160-171
Publisher: Diyala University جامعة ديالى

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ABSRACT:- This paper presents an experimental investigation that reveals bond force - slip relationships for epoxy-coated reinforcing bars under elevated temperature conditions. The obtained experimental results indicated that coating reinforcing bars with epoxy tends to degrade the residual bond strength at elevated temperatures.Keyword: bond, epoxy, bond-slip, slip, high temperature.

الخلاصةهذه الدراسة تقدم بحثا تجریبیا لاختبار تاثر مادة الایبوكسي على قوة الربط بین الكونكریت وحدید التسلیح ومدى تأثرها عند رفع درجه الحرارة وذلك بتسخین النماذج بواسطة الافران ثم اعادة تبریدها وفق قیم درجات الحرارة المعتمدة في هذه الدراسة وكما هو مبین في برنامج الاختبار. من خلال النتائج التي تم الحصول علیها تبین ان طلاء حدید بالایبوكسي یسبب تدهور في قوة الربط بین الكونكریت وحدید التسلیح وذلك في درجات الحرارة العالیة.


Article
Shear bond strength of the Iingually and buccally bonded brackets via three composite systems

Authors: Hussain A Obaidi B.D.S., M.Sc *. د. حسين العبيدي --- Naser A Khayyat B.D.S., M.Sc د. نصير خياط
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2005 Volume: 2 Issue: 2 Pages: 157-166
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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This study aimed to determine and compare the shear bond strength of linguallybonded brackets via: Two—paste composite (Orthodontic Mix Bonding System), No —mix composite [Orthodontic Bonding System (No—mix)] and Light—cured composite( Transbond XT .)Thirty extracted upper first premolars for orthodontic request were used for thisinvestigation. The teeth were divided into three groups; each of which consisted of l0teeth. The lingual surface of the tooth used to evaluate the lingual bond strength andthe buccal surface of the same tooth utilized to evaluate the buccal bond strength. Foreach group of teeth investigated to determine the lingual and buccal bond shearstrength, using one type of composite system for each group .The lingually bonded and buccally bonded samples were subjected to shearforce using the universal compression testing machine apparatus. The lingual andbuccal shear bond strengths were recorded and converted into Mpa and the data werestatistically analyzed .The results showed the lingual shear bond strength insignilicantly less than thatof buccal shear bond strength regarding the Orthodontic Mix Bonding System andOrthodontic Bonding System (No—mix), and the lingual shear bond strength wassignificantly less than the buccal shear bond strength regarding Light—curedcomposite (Transbond XT), The lingual and buccal shear strengths of the bondedbracket via Orthodontic Mix Bonding System were the highest than the shear bondstrength of the other composite systems


Article
Ising Chains Properties at Low Temperature Extended Analysis

Authors: Mansoor A_Z. Habeeb --- Nazera K. Dakhil --- Fatimah O. salman
Journal: Journal of Kufa for Mathematics and Computer مجلة الكوفة للرياضيات والحاسوب ISSN: 11712076 Year: 2014 Volume: 2 Issue: 2 Pages: 37-40
Publisher: University of Kufa جامعة الكوفة

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The transfer matrix method is used to describe the properties of the random bond of a simple periodic frustrated Ising chain in a uniform magnetic field. Doman and Williams(1982) are found expressions for the thermodynamic functions of the system at low temperature. Their methods is extended to apply to a system of five-anti ferromagnetic bond Ising chain terminated by a ferromagnetic bond at low temperatures. New expressions for the magnetization, energy, and entropy as a functions of magnetic field is found. All results are in agreement with the previous results.


Article
Evaluation of a new orthodontic bonding system (Beauty Ortho Bond)

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Background: The purpose of the current study was to evaluate the efficacy of a new orthodontic bonding system(Beauty Ortho Bond) involving the shear bond strength in dry and wet environments, and adhesion remnant index(ARI) scores evaluation in regard to other bonding systems (Heliosit and Resilience Orthodontic Adhesives).Materials and methods: Sixty defect free extracted premolars were randomly divided into six groups of 10 teetheach, mounted in acrylic resin, three groups for a dry environment and three for a wet one. Shear bond strength testwas performed with a cross head speed of 0.5 mm/min, while surfaces of enamel and bracket-adhesive-enamelsurfaces were examined with stereomicroscope For ARI scores evaluation. Data were analyzed by one way analysisof variance, least significant difference, student's t-test, and Fisher exact test.Results: The mean shear bond strength showed highest values for Resilience adhesive followed by Beauty Ortho Bondand Heliosit adhesives respectively both in dry and wet environments. Interestingly, there was a non-significantdifference (P<0.05) between Resilience and Beauty Ortho Bond adhesives using least significant difference at dryenvironment. In wet environment the Beauty Ortho Bond showed an acceptable mean shear bond strength value(6.39 Mpa) which is considered as a clinically acceptable value. Adhesive remnant index scores demonstrated atendency towards score 1 in dry environment, and towards score 3 in wet environment, the scores also showed anon-significant difference (P<0.05) between Resilience and Beauty Ortho Bond adhesives using Fischer exact test.Conclusion: Beauty Ortho Bond is less sensitive to wet environment than Resilience and Heliosit adhesives, therefore ithas an advantage during clean up, as it reduces the risk of enamel damage during debonding procedure


Article
The Effect of Two Dentin Bonding Agents on Microleakage of Ceramic Crown

Author: Nadia M. Al-Shakir
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2014 Volume: 14 Issue: 2 Pages: 196-204
Publisher: Mosul University جامعة الموصل

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Aims: The study aims to compare and investigate the effect of two bonding systems (total-etch and self-etch) bonding agents preceding the use of luting cement Variolink II Refill (Ivoclar Vivadent Schaan Liechtenstein) on the microleakage of ceramic crowns. The bonding systems compared are Excite (Ivoclar Vivadent Schaan Liechtenstein) (total-etch) and G bond (GC corporation, Tokyo, Japan) (self-etch) bonding agents. Materials and Methods: Thirty recently extracted caries-free wisdom teeth were used in this study. The teeth were cleaned and stored in distilled water until use. The molars were assigned randomly into three groups (n=10). Crown restorations were constructed by means of an indirect laboratory technique by a specialist. In group A the crown were cemented with Variolink II Refill resin luting cement alone. In group B, crowns were luted with Excite bonding agent +Variolink II Refill. In group C, G bond bonding agent+Variolink II Refill was applied prior to cementation. Results: The results showed that the higher value of microleakage with Variolink II Refill cement alone. While the least value was for the G bond+Variolink II Refill group. The results of this study revealed that the use of adhesives prior to Variolink II Refill significantly different from the use of Variolink II Refill alone in cementation of ceramic crown at (p< 0.05). Conclusions:` The analysis of results revealed statistical difference in microleakage between the first group (Variolink II Refill) cement and second ,third groups (Excite +Variolink II Refill) and (G bond + Variolink II Refill) respectively. This may indicate that, the use of adhesives prior to cementation with Variolink II Refill luting cement may decrease but not prevent microleakage.

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