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Article
Chemistry of accessory chromian spinel in serpentinites from the Penjwen ophiolite rocks, Zagros thrust zone,
تغييرات معدن الكرومايت في صخور السربنتين ضمن معقد بنجوين الافيولايتي – نطاق زاكروس الزاحف – شمال شرق العراق

Author: Sabah A.Ismail
Journal: kirkuk university journal for scientific studies مجلة جامعة كركوك - الدراسات العلمية ISSN: 19920849 / 26166801 Year: 2009 Volume: 4 Issue: 2 Pages: 1-21
Publisher: Kirkuk University جامعة كركوك

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Abstract

Chromian spinel is a widespread accessory mineral in ultramafic rocks of the Penjwen ophiolite, occurring in two modes; fresh grains in dunite rocks that crop out in the eastern part and altered grains in serpentinized peridotites in the western part of the Penjwen ophiolite. Unaltered grains are generally primary phase optically and chemically homogeneous with uniform high Cr# at ~ 0.72 and low Mg# at 0.3. High-Cr#, low-Al2O3, low-TiO2 chromites have the geochemical characteristic of chromites preserved in arc lavas and specifically overlap the field of chromites in boninites. . The cores of altered spinel grains from serpentinized harzburgite appear to retain their original igneous chemistry and are similar to fresh chromian spinel grains. The outer rim of these grains shows different degrees of alteration. Four criteria characterized the alteration process of Cr-spinel in serpentinised peridotite rocks of the Penjwen ophiolite. First, optical inhomogeneity on the scale of micrometers; chromian spinel is deep reddish brown in thin section, but opaque due to replacement by magnetite along cracks and grain boundaries. Second, chemical zonation with a decrease in Mg, Al, and Cr, increase in Fe and significant modification of minor elements (Si, Ti and Mn) towards the fractures and grain margins. Third, significant amount of SiO2¬ analyzed in Cr-spinel. Although Si does not go into the crystal structure of spinel, the microprobe analysis detected sub ordinary amount of SiO2. This suggests the presence of submicroscopic silicate phase situated at the vacancy of dissolution elements (Mg, Al, and Cr). Fourth, Ferritchromite rims and chlorite aureoles. Altered spinels deviate from primitive Cr-spinel, by sharp increase in Fe# and Cr#. The chemical changes reflect hydrothermal metamorphic reactions between spinels and the surrounding serpentinized silicate matrix.

ينتشر معدن الكرومايت بصورة واسعة في صخور الفوق قاعدية لمعقد بنجوين الافيولايتي و تتواجد بنمطين الأول الكرومايت الخالي من التحلل والمتواجد ضمن صخور الدانايت المنكشفة في الجزء الشرقي من المعقد , في حين الحبيبات المتعرضة للتحلل تظهر في صخور البيروداتايت المتعرضة لعملية السربنتنة و تنكشف في الجزء الغربي من المعقد . يتميز الكرومايت الغير متحلل باحتفاظه بالخصائص المعدنية الأصلية و تجانس صفاته البصرية و الكيميائية فضلاً عن امتلاكه لمحتوى عالي من الكروم (Cr # ~ 0.72). أظهرت الدراسة اقتصار عملية التحلل على حواف الحبيبات في الكرومايت المتحلل دون نواته . أذ تبين وجود أربعة مظاهر تحلل مختلفة : الأول عدم التجانس البصري بمقياس المايكرون إذ يظهر المعدن بلون احمر غامق مع حافة معتمة أو غامقة اللون بسبب إحلال المغنيتايت على الحافة وعلى طول التشققات .ثانياً التمنطق الكيميائي للمعدن مع نقصان في محتوى عناصر Cr, Al & Mg و زيادة في نسبة Fe مع تغيرات في محتوى العناصر الثانوية Mn, Ti, Si . ثالثاً وجود كمية منSiO¬¬2 بالرغم من ان السليكا لا تدخل في التركيب البلوري للمعدن إلا أن التحليل بواسطة المجهر الالكتروني الدقيق سجل وجود كميات من ثاني اوكسيد السليكون الذي يمكن تفسيرها بوجود أطوار معدنية للسليكا في الفراغات الناجمة من إذابة عناصر Cr, Al & Mg . رابعاً وجود حافة من معدن الكروماتايت الحديدي محاط بهالة من معدن الكلورايت . التغييرات الكيميائية لمعدن الكرومايت تعكس تفاعلات تحولية لمحاليل حرمائية بين الكرومايت الماكمائي و القاعدة السليكاتية للسربنتين .


Article
Evaluation of surface roughness of composite according to surface treatment

Author: Sabah A Ismail
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2005 Volume: 5 Issue: 2 Pages: 174-179
Publisher: Mosul University جامعة الموصل

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Abstract

The purpose of this study was to evaluate the effect ofvarious finishing and polishing procedures on the surface roughness(Ra) of two composite resins: An organically modifiedceramic (Definite) and a micro hybrid (Tetric).Thirty specimens of each composite resin were fabricatedusing a stainless steel mold of 5 mm in diameter and 2 mmin depth. The composite resin was covered by a Mylar stripand pressed flat with a microscopic glass slide and light cured.The specimens for each composite resin were divided intothree groups, each of ten. The specimens in group one receivedno treatment, while the specimens in group two and threewere finished with diamond bur. After finishing with diamondburs group three were polished with Sof–Lex discs.The surface profile of the specimens was obtained with asurface profile–testing machine (Profilometer). The roughnessvalue in micrometer (μm) was recorded as the average Ra.Results showed higher surface roughness in groups finishedwith diamond burs followed by groups finished with diamondburs and polished with Sof–Lex discs while groups setagainst Mylar strip showed the lowest roughness values. Theresult revealed no significant difference in surface roughnessvalues between the two composite resins.


Article
The effect of storage on shear bond strength of three composite resins to dentin

Author: Sabah A Ismail
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2005 Volume: 5 Issue: 1 Pages: 75-82
Publisher: Mosul University جامعة الموصل

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Abstract

The aim of this study was to determine the effect of storagetime on shear bond strength of three composite resin, twoutilize total etch technique and one utilize self etching bondingagent.One hundred twenty maxillary and mandibular molarswere used in this study. The teeth were prepared by cutting theocclusal enamel with diamond bur to expose dentin and groundwet with silicone carbide papers. The specimens were thendivided into three groups and stored in distilled water.Scotchbond Multipurpose Plus was used in the first groupand a stainless steel round mould, with a central hole of 4mm in diameter and 2 mm in height was used to build up thecomposite Z100. The composite resin was inserted in two increments,each one was light cured for 40 seconds. This gro-upis divided into four subgroups each of ten according to thestorage time (one day, fifteen days, three months and six months)then stored in distilled water accordingly.The same procedure was repeated in the second and thirdgroups. The composite used in the second group was Tetricwith Excite bonding agent. In the third group, Definite compositeand its bonding agent Etch and Prime was used.The bond strength was measured and the data were statisticallyanalyzed. Z100 composite had the greatest shear bondstrength followed by Tetric and Definite. One day and fifteendays storage time for all types of composite had greater shearbond strength than the three months and six months storagetime.In conclusion there was a gradual decrease in bond strengthwith increased storage time up to six months irrespectiveof the type of composite.


Article
An Evaluation of Coronal Seal of Root Canals Prepared by Different Systems

Author: Sabah A Ismail
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 1 Pages: 95-101
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The aim of this in vitro study was to evaluate the coronal seal of root canals prepared by two NiTi systems. Materials and Methods: Thirty-six extracted human teeth with single root canal were decoronated at the cemento-enamel junction (CEJ). The working length was determined for each tooth. Thirty teeth were divided into three groups ten of each. Group I teeth were prepared by Pro-Taper NiTi rotary instruments, then obturated by matched-taper single cone. Group II teeth were prepared by Ra-Ce NiTi rotary instruments and obturated also by matched-taper single cone. Group III teeth were pre-pared by hand K-files instrument then obturated by gutta percha lateral condensation technique. Re-maining teeth were used as control group, three positive and three negative control. Tgadeseal was used as root canal sealer for all groups in this study. Dye penetration method was used to evaluate the coro-nal seal using a steromicroscope at 40X magnification. All teeth (experimental group and control groups) were longitudinally sectioned for examination of dye penetration. One-way analysis of vari-ance and Duncan's tests was used for statistical analysis. There was significant differences between the groups (p< 0.05). Results: Statistical analysis of the results demonstrated that there was no statistical significant difference in coronal seal between the two systems. While, there was a significant differ-ence between the two rotary Ni-Ti systems and the hand K-files instrument. Conclusion: The use of Ni-Ti rotary instrument for root canal preparation shows least coronal microleakage in comparision with hand K-files instrument.


Article
Evaluation of the Surface Roughness for Three Different Types of Composite Resin Materials Using (Sof–Lex) Finishing and Polishing Systems: A Comparative Study

Author: Sabah A Ismail
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 2 Pages: 221-227
Publisher: Mosul University جامعة الموصل

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Abstract

Aim: To evaluate the surface roughness of three different types of light activated composite resin using (Sof-Lex) – polishing system, a profilometer study. Materials and Methods: A total of 30 resin com-posite disks were prepared from three different types of composite resin include 3 – groups. Group I: 10 specimens were prepared from light activated nano hybride (Tetric n – Ceram, Ivoclar – Vivadent – Liechtenstein). Group II: 10 specimens were prepared from light activated microhybride composite resin (Arabesk – Voco, Germany). Group III: 10 specimens were prepared from light activated poly-glas composite resin (Solitaire – 2, Heraeus, Kulzer, Germany). The resin blocks finished and polished using (Sof – Lex) polishing system. The specimens were analyzed for surface roughness using “Pro-filometer”. Results: Tetric n – Ceram composite resin showed the lowest roughness average (0.112 μm) followed by Arabesk composite (0.150 μm), Solitaire – 2 composite resin showed the highest roughness average (0.341 μm). Conclusions: Tetric n– Ceram (nano-hybride) was the best polished composite resin, showed the least roughness average.


Article
The effect of bleaching on shear bond strength of resin bonded bridges

Author: Sabah A ISMAIL
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2001 Volume: 1 Issue: 3 Pages: S291-S298
Publisher: Mosul University جامعة الموصل

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Abstract

Sixty intact upper central and lateral incisors were used in this study the teeth were divided into four groups, the first group was the control group the other groups were bleached with (10%)carbamide peroxide (Opalescence 10%) for two weeks the bleaching material was changed every (8) hours. Sixty discs shaped samples were cast from nickle chromium CB Blando 72 alloy the diameter of each sample was (5) mm and the thickness was (1) mm, the bonding surfaces were sandblasted. The discs were bonded to the teeth in the first and second groups one day after bleaching, the third group was bonded one week after bleaching while the fourth group was bonded two weeks after bleaching. The bonding material used for all groups was Super Bond Crown and Bridge Material. The shear bond strength of the samples was tested. The statistical analysis showed that the second group has the lowest bond strength while the fourth group showed the highest bond strength. This indicates that bleaching affects the bond strength of resin bonded bridges fabricated from CB Blando 72 nickel chromium alloy so that bridges must be fabricated at least two weeks after bleaching.


Article
Temperature rise beneath a light–cured materials using two types of curing machines

Authors: Abdul–Haq A Suliman --- Sabah A Ismail
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2006 Volume: 6 Issue: 1 Pages: 20-25
Publisher: Mosul University جامعة الموصل

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Abstract

Aim: To measure the temperature rise induced by a light emitting diode (LED) curing unit and byquartz tungsten halogen (QTH) curing unit using two types of composite resin XRV Herculite andVenus. Materials and Methods: Forty extracted non–carious single canal premolars were cleaned andbisected longitudinally. Class V preparations were cut on the buccal surfaces. The teeth were dividedinto four groups; each of ten. The teeth in the first and second groups were restored with XR–Herculitecomposite resin. The teeth in the third and fourth groups were restored with Venus composite resin.The composite resin in the first and third groups were polymerized using QTH curing unit “Astralis”for 40 seconds; the light intensity was 502 mW/cm2. The distance between the tip of the light and thecomposite was 3 + 1 mm. The composite resin in the second and fourth groups was polymerized usingLEDs “Ultra–Lite 200 E plus” curing unit for 20 seconds; the light intensity was 536 mW/cm2 usingthe same distance as the first and third groups. The temperature rise at the pulpal wall was recorded byplacing a thermocouple on the pulpal wall directly under the restoration. Results: The lowesttemperature rise during LED irradiation with Venus composite resin followed by LED irradiation withXRV Herculite composite resin. Whereas QTH curing units with XRV Herculite composite resinproduced higher values, QTH curing units with Venus composite resin produced the highesttemperature rise. Conclusion: The temperature rise of LED curing units and QTH curing units used inthis study was under the limits that affect the integrity of the dental pulp.


Article
This study concerns with the incidence of dry sockets among a sample of patients attending different dental clinics after tooth extraction for three consecutive years in relation to their age, sex, tooth location and to patients perceived stress.Dry socket patients records were investigated for age, sex and tooth location. And a control group was chosen of exactly the same age and sex distribution as that of the patients but free from any symptoms . A questionnaire sheet with a list of possible life events for the last twelve months before the extractions were distributed among both, then the results was subjected to statistical analysis.Out of 956 patients, 58 (6%) developed dry sockets, (36%) of them were located on wisdom teeth with the lower ones comprising (25.86%). There were significant difference in mean perceived psychological stress between the patients (477.07 ± 7.38 L.C.U) and those in control group (240.44 ± 7.12 L.C.U.) regarding different ages and sexes.There were higher incidence of dry sockets in this study than most other studies around the world and female /male ratio was nearly equal. They occurred mostly on lower and posterior more than upper and anterior teeth wisdom teeth were most, highly affected, and there were a relationship between psychological stress and dry socket.

Author: Sabah A. Ismail صباح عبد الوهاب اسماعيل
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2013 Volume: 2 Issue: 2 Pages: 169-174
Publisher: Tikrit University جامعة تكريت

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Abstract

The purposes of this study was to investigate the effect of sodium hypochlorite (SH) and chlorhexidine (CH) disinfectant solusions on surface texture and mechanical properties of gutta percha (GP) cones at different concentrations and time intervals. In this study, 190 GP cones size 100 were used. SH solutions at (1%, 2.5%, 5.25%) and CH solutions at (1%, 1.5%, 2%) were used for GP cones disinfection by submerging cones for (10 min, 15 min, 20 min) in each of the solutions to be tested, in which 10 cones were used for each disinfectant solution at every time interval, and 10 cones remain fresh as a control. Surface texture determined by stereomicroscope. Mechanical properties measured by digital universal testing machine. SH solutions at (2.5% and 5.25%) decrease tensile strength, increase modulus of elasticity, decrease percentage of elongation , and left a numerous pitting on GP cones after (10, 15, 20) minutes of disinfection which were significantly different from fresh control cones, 1% SH , and CH at (1%, 1.5%, 2%).Within the limitations of this study, SH at 1% and CH at (1%, 1.5%, 2%) concentrations can be considered the most safe solutions for disinfection of GP cones.


Article
Dentist laboratory communication

Authors: Sabah A Ismail --- Abdul–Haq A Suliman
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2004 Volume: 4 Issue: 2 Pages: 143-149
Publisher: Mosul University جامعة الموصل

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The aim of this study was to evaluate the common errors that may occur during crown and bridge construction. Four hundred stone models were used in this study for fabrication of 265 bridges and 135 single crown. The total number of units was 1141. Four main parameters were evaluated for each stone model: General informa-tion about the case, the condition of the stone model, the type of impression mater-ial and the prepared abutment tooth. The result of this study showed that 33.7% of the models were one unit and 48.7% of the models were 2–4 units and the remaining 17.5% of the models were more than five units, 8.7% of the models were without opposing arch. Alginate impression materials were used in 95% of the cases and only 5% of the cases elastomeric impression material were used. The finishing line was absent in 19.7% of the cases. Enough tooth reduction was done in 61.3% of the cases and 16.3% of the cases showed too much tooth reduction while 22.4% of the cases the tooth reduction was not enough. In order to avoid these errors continuous education courses and journal club are highly recommended.


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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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

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