research centers


Search results: Found 13

Listing 1 - 10 of 13 << page
of 2
>>
Sort by

Article
Comparison of Shear Bond Strength of Three Different Brackets Bonded on Zirconium Surfaces (In Vitro Study)

Authors: Saif Mauwafak سيف موفق --- Dhiaa Jaafar Al-Dabagh ضياء جعفر الدباغ
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2016 Volume: 28 Issue: 3 Pages: 142-148
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: With the increased in the demands of adult orthodontics, the challenge of direct bonding to nonenamelsurface (zirconium) had been increased. The present study was carried out to compare the shear bondstrength of three different brackets (stainless steel, sapphire and composite) bonded to zirconium surface and studythe mode of bond failure.Materials and methods: The sample was comprised of 30 models (8mm *6mm*1.5mm) of full contour zirconiumveneers. They were divided into three groups according to the brackets type; all samples were treated first bysandblast with aluminum oxide particle 50 μm then coated by z-prime plus primer. A central incisor bracket of eachgroup was bonded to the prepared zirconium surface with light cure adhesive resin (Transbond TM XT, 3M Unitek,USA). Shear bond strength was measured by using Tinius Olsen universal testing machine at crosshead speed of0.5min. After debonding, each bracket and zirconium surface were examined using magnifying lens and adhesiveremnant index was recorded. The difference in shear bond strength between main groups was analyzed by usingANOVA at p≤0.05.Results: The results revealed high significant difference among all tested groups and the highest value was forsapphire brackets (7.49±1.45 Mpa) of all groups followed by stainless steel brackets (6.46±1.43Mpa) and compositebrackets had the least value (4.35±0.72). Non-significant difference in the site of bond failure among all groups ofbrackets and zirconium-adhesive interface failure (score III) was the predominant.Conclusion: the new zirconium prime plus primer can be successfully used in bonding stainless steel and sapphirebrackets to zirconium surface.


Article
Assessment of the fracture strength of straight and pre-angled (17°) zircon implant abutments supported CADCAM zerconium restoration: An in(vitro study).

Authors: Zardasht N. Abdulghafoor --- Talal H. Al-salman --- Allaa Y. Daham
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2016 Volume: 16 Issue: 1 Pages: 77-83
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

Aims :evaluate the effect of abutment angulation on fracture strength of pre-fabricated zircon implant abutment supported CADCAM zircon crown. Material and methods: Ten analog with 3.75×14mm were placed into resin blocks divided in to 2 groups: group A (n=5) parallel to long axis and group B (n= 5) fixed at angulation (17°) to long axis. Then ten abutments were tightened to 25 N/cm2. Ten full anatomic zircon (CAD/CAM) crowns constructed as upper right central incisor: 5 on each group. After luting all crowns with dual cure resin-based luting, all samples passed to artificial aging using thermocycling machine, 500 cycles at (5 to 55 C°±2) degree. Then the load was applied by universal testing machine at 30 degree to the long axis until fracture occurred. Results: Statistical analysis showed that the implant abutment angulations significantly (p < 0.05) reduced the fracture resistance of zircon implant abutment. Conclusions: Within the limitation of this in vitro study it may be concluded that: the fracture strength of zircon implant abutment supported CADCAM zircon crown is significantly reduced in respect to the angulation fromstraight to angulated (17°) zircon abutment.


Article
Comparison of Shear Bond Strength of Sapphire Bracket Bonded to Zirconium Surface after Using Different Surface Conditioning Methods (In Vitro Study)

Authors: Hawraa Ihsan حوراء احسان --- Dhiaa Jaafar Al-Dabagh ضياء جعفر الدباغ
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2017 Volume: 29 Issue: 3 Pages: 86-92
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: The present study was carried out to compare shear bond strength of sapphire bracket bonded to zirconium surface after using different methods of surface conditioning and assessment of the adhesive remnant index.Materials and methods: The sample composed of 40 zirconium specimens divided into four groups; the first group was the control, the second group was conditioned by sandblast with aluminum oxide particle 50 μm, the third and fourth group was treated by (Nd: YAG) laser (1064nm)(0.888 Watt for 5 seconds) for the 1st laser group and (0.444 Watt for 10 seconds) for the 2nd laser group. All samples were coated by z-prime plus primer. A central incisor sapphire bracket was bonded to all samples with light cure adhesive resin. Shear bond strength was measured by using Tinius Olsen universal testing machine. After debonding, each bracket and zirconium surface were examined and adhesive remnant index was registered. The difference in shear bond strength among groups was analyzed by using ANOVA test. The adhesive remnant index was assessed using Chi-square test.Results: The 2nd laser group had the highest mean value of shear bond strength then the 1st laser group followed by the sandblasting group, while the control group had the least value, non-significant difference in the shear bond strength was found between the laser groups and highly significant difference was found between all other comparable groups. Non-significant difference in the site of bond failure was found between the laser groups and sandblasting group, and between the two laser groups.Conclusion: The laser conditioning method showed higher value of shear bond strength than the sandblasting conditioning method


Article
Phthalanilinc Acid Complexes of Titanium (IV) and Zirconium (IV)

Authors: Wijdan A. Al-Zeadan --- Roaa Haddad
Journal: Tikrit Journal of Pure Science مجلة تكريت للعلوم الصرفة ISSN: 18131662 Year: 2012 Volume: 17 Issue: 4 Pages: 67-71
Publisher: Tikrit University جامعة تكريت

Loading...
Loading...
Abstract

In this paper we report the synthesis of a number of titanium (IV) and zirconium (IV) complexes of the formulas [Ti(LH2)Cl2]Cl2 ,[Zr(LH2)2](NO3)4 , [ZrO(LH2)]Cl2, [Ti(L)Cl2] ,[Zr(L)2] , [Zr(OH)2(L)], by the reaction of the phthalanilic acid ligand, furfuroylhydrazido-ortho-acetobenzoic acid (LH2, scheme 1), with titanium tetrachloride, zirconium nitrate or zirconyl chloride. The ligand prepared by the reaction of furfuroylhydrazide with phthalic anhydride. Reactions of this ligand with the metal salts in both neutral and basic solutions gave cationic and neutral complexes, respectively. The prepared ligand and its complexes were characterized by elemental analysis, molar conductance and by infrared and ultraviolet spectra. In all complexes the ligand acts as neutral tetradentate in neutral medium and dibasic tetradentate in basic medium. Titanium complexes are hexacoordinated with octahedral structure, while zirconium complexes have different structures. Zirconium nitrate complexes are octacoordinated with the most probable square antiprism geometry. On the other hand, the two complexes of zirconyl chloride obtained from neutral and basic media are penta- and hexa-coordinated with the most common square pyramidal and octahedral structures, respectively.

تضمن هذا البحث تحضير عدد من معقدات التيتانيوم والزركونيوم مع الليكاند من نوع حامض الفثالانيليك، فورفورايل هيدرازيدو-أورثو-أسيتو حامض بنزويك (LH2، المخطط رقم 1)، وذلك بتفاعل رباعي نترات الزركونيوم وكلوريد الزركونيل مع الليكاند المذكور. تم الحصول على الليكاند من تفاعل هيدرازيد الفورفوريل مع أنهدريد الفثالانيليك. وحضرت المعقدات في كل من الوسطين المتعادل والقاعدي، إذ نتج عن الوسط المتعادل معقدات أيونية موجبة ذات الصيغ، [Ti(LH2)Cl2]Cl2 و [Zr(LH2)2](NO3)4 و [ZrO(LH2)]Cl2، في حين أعطى الوسط القاعدي معقدات متعادلة لها الصيغ، [Ti(L)Cl2] و [Zr(L)2] و [Zr(OH)2(L)]. وتم تشخيص الليكاند ومعقداته بالتحليل الدقيق للعناصر وقياسات التوصيل الكهربائي وأطياف الأشعة تحت الحمراء وفوق البنفسجية.وقد دلت التحاليل على أن الليكاند يسلك بشكل رباعي السن متعادل في الوسط المتعادل ورباعي السن ثنائي القاعدة في الوسط القاعدي. واتضح أن أيون التيتانيوم في هذه المعقدات يتخذ التناسق السداسي ذو بنية ثماني السطوح، ويأخذ أيون الزركونيوم التناسق الثماني ذو بنية معكوس الموشور المربع، الأكثر احتمالاً. من ناحية اخرى، اتضح أن لمعقد كلوريد الزركونيل الناتج عن الوسط المتعادل التناسق الخماسي ذو بنية الهرم المربع الأكثر شيوعاً. في حين أظهر معقد كلوريد الزركونيل الناتج عن الوسط القاعدي التناسق السداسي ذو بنية ثماني السطوح الشائعة.


Article
The Effect of Addition of Zirconium Nano Particles on Antifungal Activity and Some Properties of Soft Denture Lining Material

Authors: Alaa Dakhil Yasser علاء داخل ياسر --- Nabeel Abdul Fatah نبيل عبدالفتاح
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2017 Volume: 29 Issue: 4 Pages: 27-32
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background Microorganisms and fungal growth especially Candida albicans, on soft denture lining material are the most common problem which can lead to chronic mucosal inflammation. The aim of this study was to evaluate the effect of zirconium nanoparticles into acrylic-based heat cured soft denture lining material against Candida albicans, and the amount of zirconium ion release of soft liner/ZrNPs composite. Furthermore, evaluate shear bond strength after ZrNPs addition to soft liner.Materials and methods: Zirconium nanoparticles were added into acrylic-based soft denture liner in various percentages (1%, and 1.5% by weight). Two hundred and fifty specimens were arranged and isolated into four groups as per the test to be done The antifungal activity of the soft liner/ZrNPs composite was assessed in three different periods by using two methods (viable count of C. albicans and disk-diffusion test). In two distinct periods, amount of zirconium released in artificial saliva was detected by atomic absorption spectroscopy. Instron testing machine was used to test the shear bond strength of the soft liner to the acrylic denture base material.Results: A highly significant decrease in colony forming units of C. albicans in experimental groups (1% and 1.5%ZrNPs) contrast with control group. There was no inhibition zone around any specimen of any test group. In artificial saliva there was no zirconium distinguished to be released at any incubation period. There was a highly significant increase in the mean value of shear bonding strength after incorporation of ZrNPs at 1.5% percentage into soft liner.Conclusion: The addition of ZrNPs into acrylic-based soft denture lining material helps to provide soft denture liner with antifungal properties, thus reducing the susceptibility to develop denture-induced stomatitis. There is no zirconium has been detected at any incubation period and there is increased in the shear bond strength of the soft lining material.


Article
An in vitro evaluation of fit of the crowns fabricated by zirconium oxide-based ceramic CAD/CAM systems, before and after porcelain firing cycles and after glaze cycles

Authors: Sattar J. A. Hmedat ستار حميدات --- Adel F. Ibraheem عادل فرحان ابراهيم
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: 1 Pages: 43-48
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: The objective of this in vitro study was to evaluate the vertical marginal fit of crowns fabricated withZrO2 CAD/CAM, before and after porcelain firing cycles and after glaze cycles.Materials and Methods: An acrylic resin model of a left maxillary first molar was prepared and duplicated to haveNickel-Chromium master die. Ten die stone dies were sent to the CAD/CAM (Amann Girrbach) for crownsfabrication. Marginal gaps along vertical planes were measured at four indentations at the (mid mesial, mid distal,mid buccal, mid palatal) before (Time 0) and after porcelain firing cycles (Time 1) and after glaze cycles (Time 2)using a light microscope at a magnification of ~100. One way ANOVA LSD tests were performed to determinewhether the mean and standard deviation of sub group Time 2.Results: The mean values of the ZrO2 CAD/CAM Time 0 were (6.77ƒÊm), Time 1(8.75ƒÊm) and Time 2(10.62 ƒÊm). Oneway ANOVA test revealed highly statistical significance(P<0.01). LSD test results showed that there is highly significantdifference between time (0) and time (2), while there is no any significant difference between time (0) and time (1),and between time (1) and time (2).Conclusions: Within the limitations of this study, it was concluded that the ZrO2 CAD/CAM demonstrated acceptablemarginal fit; The porcelain firing and the glaze firing cycles affected the marginal gap


Article
A Study the Effect of Addition of Silanized Zirconium Oxide Nanoparticles on Some Properties of High-Impact Heat-Cured Acrylic Resin

Authors: Soodad A. Al-Hiloh سوداد الحلو --- Intisar J. Ismail انتصار جميل اسماعيل
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2016 Volume: 28 Issue: 2 Pages: 19-25
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: The incorporation of rubber has not been entirely successful because it can have detrimental effectson the transverse Strength and hence the rigidity of the denture base.Materials and methods: Zirconium oxide nanoparticales were coated with a layer oftrimethoxysilylpropylmethacrylate (TMSPM) before sonication in monomer (MMA) with the percentages 3% byweight then mixed with powder using conventional procedure.(100) samples were prepared and divided into fivegroups according to the test performed ,Each group consisted of 20 specimens and these were subdivided into 2groupsGroup (A): control group (10 specimens of high impact acrylic resin without zirconium oxide) and Group(B):zirconium oxide group(10 specimens of high impact acrylic resin with 3% wt zirconium oxide).The testsconducted were impact strength, transverse strength, indentation hardness(shore D), surface roughness, watersorption and solubility. The results were statistically analyzed using Dunntt t-test.Results: Highly significant increase in impact strength and transverse strength occurred with the incorporation of 3%wt Zirconium oxide nanofiller. A highly significant increase in surface hardness, but the water sorption and solubilitywere significantly decreased with the addition of silanized (ZrO2) Nano particles compared with the control group.nosignificant statistical difference in surface roughness.Conclusions: The addition of silanized ZrO2 Nano particles to high impact heat cure acrylic resin material improves theimpact strength, transverse strength and surface hardness of high-impact heat-cure acrylic resin at the same timethis addition decreases water sorption and solubility. On the other hand there was no change in surface roughnesswith the addition of 3% wt of silanized ZrO2Nano particles


Article
A Novel Use of Biomaterial Implants For Reconstruction of Orbital Floor Fracture

Authors: Kamal Turki Aftan --- Elham Hazeim Abdulkareem
Journal: Journal of Oral and Dental Research مجلة طب الفم والاسنان ISSN: 23106417 Year: 2017 Volume: 4 Issue: 1 Pages: 25-34
Publisher: Iraqi Association for Oral Research الجمعية العراقية لبحوث طب الفم


Article
Effect of Accelerated Weathering on the Compressive Strength for PMMA Nano Composites and PMMA Hybrids Nano Composites Used in Dental Applications

Authors: S.I. Salih --- J.K. Oleiwi --- A.M. Talia
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2017 Volume: 35 Issue: 3 Part (A) Engineering Pages: 204-215
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

In the present research, efforts are made to develop the properties of PMMA resin that used for upper and lower prosthesis complete denture, by addition four different types of nanoparticles powders, which are fly ash, fly dust, zirconia and aluminum that added with different ratios of volume fractions of (0.01, 0.02 and 0.03) to poly methyl methacrylate (PMMA), cold cured resin (castavaria) is the new fluid resin (pour type) as a matrix. The nano composite and hybrid nano composite for prosthetic dentures specimens, preparation was done by using (Hand Lay-Up) method as six groups which includes: the first three groups consists of PMMA resin reinforced by fly ash , fly dust and ZrO2 nanoparticles respectively, the second three groups consists of three types of hybrid nano composites, which includes ((PMMA:X% fly ash) - (1%Al + 3%ZrO2)), ((PMMA:X% fly dust) - (1% Al + 3%ZrO2)) and ((PMMA:nZrO2) - (1% fly ash+ 3% fly dust)) respectively. As well as, the effect of moisture and UV was taking into consideration in this study. The compression test results shows that the values of compressive strength, compressive elastic modulus, and compressive strength under the effect of accelerated weathering (moisture and UV radiation) increased with the addition of nano powders (fly ash, fly dust, zirconia and aluminum). As well as, the results showed that the maximum values of compressive strength reach to (286.25MPa) for (PMMA + 2%nZrO2) nano composite. In addition, the results showed that the compressive elastic modulus reach to the maximum value (25.4166GPa) in the nano composite material (PMMA + 2%nZrO2). Moreover, the results showed that the compressive strength under the effect of accelerated weathering (moisture and UV radiation) reach to the maximum value to (315MPa) for the nano composite material (PMMA + 3%nZrO2).


Article
Study Mechanical and Thermal Properties of ZrO2/PMMA Nanocompsites
دراسة الخصائص الميكانيكية والحرارية لمتراكبات نانوية لـ ZrO2/PMMA

Authors: Noor Dhaief f Al-Shwak نور ظايف الشواك --- Najiba Abdullah Al-Hamadani نجيبة عبد الله الحمداني
Journal: Diyala Journal For Pure Science مجلة ديالى للعلوم الصرفة ISSN: 83732222 25189255 Year: 2016 Volume: 12 Issue: 2 Pages: 1-10
Publisher: Diyala University جامعة ديالى

Loading...
Loading...
Abstract

In this research, nanocomposites of thermoplastic polymer (Poly Methyl Methacrylate, PMMA) and nanoparticles reinforcement (Zirconium Oxides, ZrO2) have been fabricated by solution casting method. ZrO2/PMMA nanocomposites have been prepared with different weight fraction (0, 1, 1.5, 2.5, 3 and 5 wt%) of ZrO2 particles with help of chloroform as a solvent. Some physical properties, such as : mechanical properties (tensile strength, hardness), thermal properties (glass transition temperature, thermal conductivity) of prepared samples as a function of weight fraction(concentration) of ZrO2 in nanocomposites have been investigated. Mechanical properties showed that the tensile strength and hardness increases with increasing ZrO2 concentration, and the hardness reached their maximum value at 1 wt% of ZrO2. Thermal properties results shown increase in glass transition temperature and thermal conductivity as ZrO2 weight fraction increase, and the thermal conductivity reached highest value at 1 wt% of ZrO2.

تم في هذا البحث تحضير المتراكبات النانوية للبوليمر المطاوع للحرارة (بولي مثيل ميثااكريلايت, PMMA) والمدعم بالجسيمات النانوية (اوكسيد الزركونيوم، ZrO2) بطريقة صب المحلول. تم تحضير المتراكبات النانوية بكسور وزنية مختلفة (%1,1.5,2.5,3.5wt) باستخدام الكلوروفورم كمذيب. ثم دراسة بعض الخصائص الفيزيائية للنماذج المحضرة المتمثلة بالخصائص الميكانيكية (ألشد, الصلادة) و الخصائص الحرارية (درجة الانتقال ألزجاجي التوصيلية الحرارية) . اشارت نتائج الخصائص الميكانيكية زيادة في قيمة اجهاد الشد, والصلادة بزيادة النسبة الوزنية (التركيز) لـ ZrO2 وان اعظم صلادة كانت عند نسبة % 1 لـ ZrO2 . كذلك اظهرت نتائج الخصائص الحرارية زيادة في درجة الانتقال الزجاجي والتوصيلية الحرارية بزيادة نسبة ZrO2 وان اعظم توصيلية كانت عند نسبة تدعيم %1 لـ ZrO2 .

Listing 1 - 10 of 13 << page
of 2
>>
Sort by
Narrow your search

Resource type

article (13)


Language

English (12)

Arabic (1)


Year
From To Submit

2017 (5)

2016 (6)

2013 (1)

2012 (1)