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Article
Biocompatibility of Soldering Materials Used for Repair of Cobalt Chromium Joints

Authors: Nadira A Hatim --- Nazar Gh Jameel --- Abdullah J Mohammed
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 1 Pages: 7-13
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The aim of this study is to evaluate the biological activities of three soldering materials used for joining Co-Cr joints (iron, stainless steel, and brass) on the tissue of the Rabbit. Materials and Meth-ods: Nine specimens of each iron, stainless steel, and brass where made as cylinders (3mm x 2.5mm). The middle part was made of the brazing materials and the upper and lower parts were made of Co-Cr. These specimens where implanted in the subcutaneous tissue of the rabbit, after two weeks the animals where sacrificed and biopsies where made and examined under microscope by three oral pathologists. Results: Stainless steel implants were the most biocompatible material among the three materials used as brazing materials. Stainless steel sites had insignificant differences with the control sites. Significant difference was found between the iron implanted sites and the control group. This result found by two viewers (A, and M), while the third viewer (Z) found no significant difference between the control group, and the iron implanted sites. Significant difference was found between the brass implanted sites and the control group, this result was found by the three viewers (A, M, and Z). Conclusions: The stainless steel had the most favorable tissue response among the three soldering materials, iron is in the second rank, and brass showed unfavorable tissue response due to release of Cu.


Article
The Influence of Natural Products as Denture Cleansers on Candida albicans Colonization to Cobalt–Chromium Alloy Denture Base Ma-terial.

Author: Nadia T Jaffer
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2011 Volume: 11 Issue: 1 Pages: 124-130
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The study aims to evaluate the influence of various denture cleansers on colonization of Candi-da albicans to Cobalt–Chromium alloy denture base and the subsequent roughness assosiated with these cleansers. Materials and methods: Thirty–six samples of Co–Cr denture base and five cleansers, four prepared(alum, salt, soda+vinegar, soda+thymol), one commercial ( protefix ) and distilled wa-ter(D.W) as a control were used. Samples were immersed in denture cleansers for one month in which each cleanser had 6 samples excluding 6 samples in D.W as a control. Half of samples for each cleans-er were immersed ½ hr per day and the other half immersed 8hrs per day through one month, before microbiological examination, samples were tested for surface roughness using profilometer. Candida albicans cell suspension was incubated with the test samples for 1hr at 37°C after which the test sam-ples were immersed in their cleansers for 1hr. Visualization, inspection and enumeration of adherent C.albicans cells and detection of the anti–adherent effect of the cleansers was achieved by using light microscopy. Results: The results demonstrated insignificant difference in surface roughness of Co–Cr alloy denture base in the cleansers at 1/2 hr and a significant difference at 8 hrs immersion. There was a significant difference in C.albicans colonization to Co–Cr denture base in which all the cleansers showed less adhesion than control. The results also revealed that (soda+Thymol oil) cleanser ex-pressed the least values of colonization and roughness among other cleansers. Conclusions: The cleansers were effective as anti–adherent yeast cells to Co–Cr denture base and showed roughness de-grees less than control


Article
Study of Corrosion Resistance of Co-Cr-Mo Surgical Implants Alloy in Artificial Saliva
دراسة مقاومة التاكل لسبيكة الزوارع الجراحية ذات اساس كوبلت-كروم- مولبدنيوم في اللعاب الاصطناعي

Authors: Muna Khethier Abbass --- Sami Abualnoun Ajeel --- Haitham M. Wadullah
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2014 Volume: 32 Issue: 10 Part (A) Engineering Pages: 2331-2339
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Co-Cr-Mo alloy has been used for biomedical implant for a number of years. In this study, ASTM F-75 Cobalt-base substrate specimen was immersed in artificial saliva at 37 + 1 ºC to study the corrosion resistance properties. Surface of specimen before and after the immersion was analyzed by optical microscope and Scanning Electron Microscopy (SEM). X-Ray Diffraction (XRD) was used to study the phase structure present. The metallic ions in the artificial saliva were analyzed after the corrosion test by Absorption Spectrophotometer (AAS). Electrochemical Measurements by polarization experiments were performed to study the corrosion resistance, the main results obtained were expressed in terms of the corrosion potentials (Ecorr) and corrosion current density (icorr) in addition to measure the Tafel slops by Tafel extrapolation method, and also cyclic polarization are used in artificial saliva solution. The results of galvanic corrosion show that the Co-Cr-Mo alloy had localized corrosion in artificial saliva at 37+1ºC.

تستخدم سبيكة كوبلت – كروم – مولبيدينيوم في زراعة المواد الطيبة لسنوات عديدة . في هذه الدراسة ، غمرت نماذج سبيكة ASTM F-75 ذات الاساس كوبلت في اللعاب الصناعي بدرجة حرارة 37 + 1درجة مئوية لدراسة مقاومتها للتآكل. تم تحليل سطح النماذج قبل وبعد التآكل باستخدام المجهرالضوئي والمجهرالالكتروني الماسح (SEM). وكذلك تم دراسة حيود الاشعة السينية ( X-Ray Diffraction) لدراسة الاطوار الموجودة في السبيكة. واجراء تحليل للايونات المعدنية في سائل اللعاب الصناعي بعد اختبار التآكل. أجريت القياسات الكهروكيميائية بواسطة تجارب الاستقطاب لدراسة مقاومة التآكل، والنتائج الرئيسية التي تم الحصول عليها بعد التعرض للعاب الصناعي تتمثل بجهد التآكل(Ecorr) وكثافة تيارالتآكل (icorr) بالإضافة إلى قياس ميول تافل لمنحنيات تافل( Tafel ) بطريقة تافل للاستقراء وكذلك الاستقطاب الحلقي في اللعاب الاصطناعي. تبين نتائج التأكل الكلفاني بان سبيكة كوبلت- كروم- مولبيدينيوم المطلية تتآكل موضعيا في اللعاب الاصطناعي عند درجة حرارة 37 درجة مئوية.


Article
Effect Of Surface Treatment on Shear Bond Strength of Acrylic Resin to Cobalt-Chromium Alloy

Author: Mohammed M.Sadoon
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2014 Volume: 14 Issue: 2 Pages: 252-258
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: to evaluate the effect of metal primer with acid etch, laser beam, and sand blasting on shear bond strength(SBS) or resin metal and surface roughness(SR). Materials and methods: fifty Co-Cr metal plate were prepared with 10X10X1 mm dimensions. These metal plates were divided in to 5 groups control (without treatment), acid etched with hydrochloric acid(10%) with metal primer(AP), laser beam with metal primer(LP), sand blasting with metal primer(SP), and metal primer alone(P). These groups were tested for shear bond strength of resin to metal and surface roughness. Results: there are a significant differences in shear bond strength of all treated groups in contrast to control groups, and the AP had the highest shear bond strength value. While surface roughness of tested samples shows the control group smoothest surface in relation to other groups and there is no significant difference with metal primer only and the AP group had higher surfaces roughness. Conclusion: metal primer improve bond strength between Co-Cr and chemical cured acrylic resin, the treating surface with HCL acid increase SBS and SR of metal plate. The roughening of metal surface by different treatment ( P, AP, LP, and SP) improve the SBS of metal bond to resin.


Article
Effect of Some Anti-Inflammatory Drugs on The Corrosion Behavior of Implant Biomaterials in Human Body Fluid
تأثير بعض الادوية المضادة للالتهاب على سلوك تاكل المواد الحيوية المزروعة في محيط جسم الانسان

Authors: Kahtan K.Al-Khazraji --- Ali H. Ataiwi --- Rana A. Majed --- Zina Noori Abdulhameed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2012 Volume: 30 Issue: 6 Pages: 959-973
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The aim of this research is to compare the electrochemical behavior of two surgical implant biomaterials alloys, SS 316L and Co–Cr–Mo alloy in simulated body fluid. This comparison is focused on the influence of presence of three anti-inflammatory drugs, aspirin (C9H8O4), paracetamol (C8H9NO2), and mefenamic acid (C15H15NO2) with threeconcentrations of each drug (0.00303, 0.00606, and 0.01212), (0.0086, 0.0172, and 0.0344), and (0.00111, 0.00156, and 0.00201) g/300ml respectively at pH=7.4 and 37oC using electrochemical techniques, potentiodynamic curves and potentiostatic tests. Influence of these drugs on both biomaterials depends on the formation oforganometallic complexes between released metals ions from implant alloys and drugs molecules. The study shows that the drugs behave as inhibitors for SS 316L through the measured corrosion parameters, while gives irregular behavior in the case of Co – Cr – Mo alloy. However, difference between two alloys appear with different affinity ofreleased metal ions to binding with other molecules inside human body.


Article
Thermal expansion of prepared dental base-metal casting alloys

Author: Mohammed Talib Al-khafagy محمد طالب الخفاجي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 1 Pages: 17-22
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: This study aimed to evaluate the linear thermal expansion of prepared Ni-Cr and Co-Cr dental basemetalcasting alloys which has been prepared locally in Iraq and compare with other conventional alloys.Materials and methods: Cylindrical shape wax specimen was prepared of (15mm) length and (5mm) diameter,which invested in phosphate-bonded investment material and casted by using induction-casting machine. The linerthermal expansion has been tested by using Iraqi-made dialometer in which the furnace was set to reach from roomtemperature to 950 C in a rate of 10 C per minute.Results and discussion: The prepared Ni-Cr and Co-Cr alloys were showed a higher linear thermal expansion than theconventional alloys, however, statistical analysis revealed non-significant differences regarding the Co-Cr alloys andhighly significant differences regarding the Ni-Cr alloys


Article
Effect of different metal surface treatments and thermocycling on shear bond strength of heat cure and light cure at Co/Cr and Ni/Cr interface

Authors: Ali M. Khursheed علي خورشيد --- Salah A. Mohammed صلاح محمد
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 2 Pages: 1-5
Publisher: Baghdad University جامعة بغداد

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Abstract

Background Optimum bond strength at the metal – resin interface of prosthesis is essential for the success of thatprosthesis. The junction between metal alloy and acrylic resin is an area of clinical concern .Failure of a R.P.D. maybe linked to this interface. The main objective of this study were to determine the effect of different metal surfacetreatment and thermocycling on the shear bond strength of Co/Cr alloy and Ni/Cr alloy to heat cure acrylic resinand light cure acrylic resin.Materials and methods: 120 metal samples were prepared, 60 Co/Cr samples and 60 Ni/Cr of square flat plate (30mm x 30mm x 2 mm) that incorporated a central area (8mmx 12mm) of a large retentive mesh to simulate dentureframework. The samples were cleaned, finished and electropolished. Sixty samples of each type of metals weredivided into two groups according to the type of acrylic resin received each one 30 samples (A and group C) forheat cure, B and group D for light cure) which were furtherly subdivided according to the type of surface treatmentinto 3 subgroups each one 10 samples(A1 ,B1 ,C1and D1 )for no surface treatment, no thermocycling as a controlgroup (A2, B2 ,C2 and D2 )for Metal Prime II application with thermocycling (A3, B3 ,C3 and D3) for combination ofAir Abrasion and Metal Primer II application with thermocycling. The acrylic block were then prepared as arectangular block(12mm length ,8 mm width ,6 mm high )that was placed on a central area of metal plates, theacrylic was fabricated in the same conventional way of denture construction. All the sample were mounted onspecially test fixture that would hold them rigid at a 90-degree angle from the horizontal plane of the crosshead ofthe Instron machine .A tangent shear force was created by applying vertical load to the specimen .All of thespecimen were tested with Instron machine using stainless steel chisel shaped road at a constant crosshead speed of5 mm min until failure of the bond occurred The specimen were stressed to failure .The force of bond failure wasrecorded in Newton, which was divide by the surface of the bonded area (96 mm2 )to obtain the shear bondstrength calculated in Mpa.Result: The results showed that the subgroup that received no surface treatment and without thermocycling for bothtwo type of resins heat cure and light cure (A1, B1, C1and D1) had the highest shear bond values, followed bysubgroups that received Air Abrasion + Metal Primer II surface treatments and thermocycling (A3, B3, C3,D3).Subgroups that received Metal Primer II alone (A2, B2, C2 and D2) showed the least shear bond value than theother subgroups.Conclusion: All metal samples of Co/Cr and Ni/Cr with heat cure acrylic resin showed higher SBS mean values thanthat light cure resin whether with surface treatment and thermocycling or without thermocycling concluded higherbinding of heat cure acrylic resin with the metal surface

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