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Article
The Effect of Sodium Hypochlorite on Shear Bond between Composite and Porcelain Specimens

Authors: Ashraf S Qassim --- Sabah A Ismail --- Emad F Alkhalidi
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2012 Volume: 12 Issue: 2 Pages: 316-320
Publisher: Mosul University جامعة الموصل

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Abstract

Aim of Study: This in vitro study was conducted to evaluate the shear bond strength of intra oral por-celain repair system using 10% sodium hypochlorite and different acid etch. Materials and methods: Forty specimens were prepared in form of metal disks (8mm in diameter, 15mm height) and porcelain was applied according to the manufacturer instructions.The specimens randomly divided into 4 equal groups. In Group I ,II the samples were treated with 9% hydrofluoric acid for one minute. While groups III, IV were treated with 37% phosphoric acid for one minute, after washing the specimens with water and dryness, groups II, III the surfaces treated with 10%sodium hypochlorite for one minute while group I and IV leaved untreated. After that, the surfaces of all samples were washed and dried and silane coupling agent (MonoBond-S Vivadent, Liechtenstein) was applied according to the manu-facturer instructions, then bonding agent (Excite) (Vivadent, Liechtenstein) and composite (tetric N–ceram) (Vivadent, Liechtenstein) were applied according to the manufacturer instructions. All the sam-ples were stored in normal physiological saline for 7 days. Then the samples were thermocycled ma-nually between two water baths After that Shear bond strength was tested using universal testing ma-chine. Results: using ANOVA and Duncan’s multiple range tests. The result showed that there was highly significant difference between groups treated with 10%sodium hypochlorite with untreated one. There was significant difference between samples acid etched using hydrofluoric acid with those etched with phosphoric acid. Conclusions: Sodium hypochlorite and hydrofluoric acid significantly increase the shear bond strength between composite resin and porcelain fused to metal specimens


Article
Evaluation of Shear Bond Strength of Ceramic Repair With Resin Composite

Author: Emad F Al–Khalidi
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 3 Pages: S119-S123
Publisher: Mosul University جامعة الموصل

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Abstract

Aim: To evaluate the shear bond strength of intra oral porcelain repair system using different surface treatments when fracture of porcelain with complete metal exposure. Materials and Methods: forty specimens were prepared in form of metal disks (8mm in diameter, this diameter is for each specimen and 15mm height) and randomly divided into 4 equal groups. The first two groups were treated with air abrasion. The other groups leaved untouched. Groups I and III were treated with 37% phosphoric acid while in groups II and IV the surface were treated with 9% hydrofluoric acid, after that the surfaces of all samples were treated with silane coupling agent then bonding and composite were applied according to the manufacturer instructions. All the samples were stored in a normal physiological saline for 7 days. Then the samples were thermocycled after that Shear bond strength was tested using universal testing machine. Results: The result showed that there was a highly significant difference between groups treated with Al2O3 with those untreated one, the acid etch material. There was a highly significant difference between samples acid etched using hydrofluoric acid with those etched with phosphoric acid. Conclusion: Air abrasion and the hydrofluoric acid significantly increase the shear bond strength between composite resin and exposed metal of metal ceramic restoration


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
FATIGUE LIFE ENHANCEMENT OF AL-ALLOY7075 UNDER COMBINED LASER ANDHYDROFLUORIC ACID INTERACTION
تحسين عمر الكلال لسبيكة الالمنيوم 7075تحت تأثير تفاعل مشترك لليزر وحامض الهيدروفلوريك

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Abstract

Laser shock peening (LSP) is a technical method for generation the compressive residual stress. LSP has been shown to greatly improve fatigue strength and lifetime. A study of fatigue under a constant repeating bending stress has been conducted on AL-alloy 7075 alloy at a stress ratio (R= -1) and room temperature using laser peening technique with overlay hydrofluoric acid (HF) as a confinement acid layer and as a media to increase the penetration of laser pulses. Two groups of test have been considered. The first group (15 specimens) was examined under unpeened situation. The second group (15 specimens) was examined under acid laser peening (ACLP). All mentioned groups were tested to generate the S - N curve. hydrofluoric acid (HF) coating was used as a new technique to improve the properties of the AL-alloy 7075. The experimental data showed that the use of (HF) acid, as a coating material, largely increased the compressive residual stress at the surface. The results provided a substantial improvement in fatigue life improvement factor reaching to 80% for this new coating.

الصعق باستخدام الليزر تعتبر من الطرق الحديثة لتوليد جهد متبقي ولتحسين مقاومة الكلال والعمر التشغيلي . تمت الدراسة في ظروف حمل مستمر ترددي وبدرجة حرارة الغرفة مع استخدام تغطية سطح السبيكة بحامض فلوريد الهيدروجين بعد عزله عن السبيكة لزيادة نفوذية نبضات الليزر. وقد استعملت مجموعتين ، كل مجموعة تتكون من 15 قطعة وفحصت الاولى بدون تاثير الليزر والثانية تحت تاثير الليزر وبوجود الحامض يغطي السبيكة .الغاية هو لغرض عمل مخطط الاجهاد مع عدد الدورات.يعتبر استخدام الحامض فلوريد الهيدروجين تقنية جديدة لتحسين خواص سبيكة الالمنيوم 7075 . وأظهرت النتائج باستخدام هذه الطريقة زيادة كبيرة في الاجهاد الانضغاطي المتبقي على سطح المعدن وكذلك تحسن في معامل تحسن خواص الكلال بنسبة تصل الى 80 % لطبقة الطلاء الجديدة .

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