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An Evaluation of the Effect of Bleaching Agent on Microhardness of a New Silorane-Based Restorative System and Methacrylate-Based Restorative Material

Authors: Shatha Abdul Kareem --- Rasha Hameid Jehad
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2012 Volume: 20 Issue: 1 Pages: 385-363
Publisher: Babylon University جامعة بابل

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Abstract

Background: The high reactivity of hydrogen peroxide used in bleaching agents have raised important questions on their potential adverse effects on physical properties of restorative materials. The purpose of this in vitro study was to evaluate the effect of in-office bleaching agents on the microhardness of a new Silorane-based restorative material in comparison to methacrylate-based restorative material.Materials and method: Forty specimens of Filtek™ P90 (3M ESPE,USA) and Filtek™ Supreme XT (3M ESPE, USA) of (8mm diameter and 3m height) were prepared. All specimens were polished with Sof-Lex disks (3M ESPE, USA). All samples were rinsed and stored in incubator 37˚C for 24 hours in DDW. Ten sample of each material were subjected to 37.5% hydrogen peroxide gel (Pola office +, SDI)for 8 minutes while exposed to light curing device, this step was repeated three times for 3 weeks. While the other ten samples for each material was served as control. All specimens were subjected to microhardness test using digital microhardness tester to determine the VHN (Vickers Hardness Number)Results : The Filtek™ P90 exhibited higher microhardness value than Filtek™ Supreme XT. After hydrogen peroxide treatment, both types of composites exhibited low microhardness values but still Filtek™ P90 is harder than Filtek™ Supreme XT.Conclusion : In-office hydrogen peroxide bleaching agent resulted in reduction in microhardness values for both composite materials. Silorane- based composite is more affected by the bleaching agent than methacrylate-based composite.


Article
A comparative study to evaluate the sealing ability of a prisma dycal placed in cervical root perforation versus other materials (in vitro study)

Authors: Ahmed H. Ali احمد علي --- Raghad A. Mohammed رغد محمد --- Shatha Abdul- Kareem شذى عبد الكريم
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2005 Volume: 17 Issue: 3 Pages: 1-3
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Calcium Hydroxide preparations are used extensively in dentistry, and one of these aspects is treatment of root perforations. The purpose of this in vitro study was to compare the sealing ability of a prisma (visible light cure dycal), amalgam with varnish and chemical cure dycal are used to repair lateral root perforations.Materials and Methods: Thirty extracted human maxillary anterior teeth were used; each tooth was sectioned longitudinally into facial and palatal halves .The perforations were made into each half tooth at the cervical third of the root. The samples were divided into three groups; group I was repaired with prisma, group II repaired with chemically cured dycal and group III with varnish and amalgam .The teeth halves were placed in methylene blue dye for one week period then linear dye penetration was measured from where the repair materials were made.Results: The results showed that a prisma (visible light cure dycal) demonstrated less dye penetration than other groups, the difference was statistically significant (p<0.01) from other groups, non significant differences (p>0.05) were present between amalgam with varnish and the chemically cured dycal.Conclusion: Calcium Hydroxide including the visible light cured and the chemically cured, and the amalgam with varnish, each possess a therapeutic potential for treating known and undetected root perforations. Percentage of leakage was more in amalgam with varnish group than prisma and Kerr Dycal


Article
An evaluation of water absorption of Giomer in comparison to other resin-based restorative materials

Authors: Shatha Abdul Kareem شذى عبد الكريم --- Rasha H. Jehad رشا جهاد
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 3 Pages: 25-28
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Polymeric composites have been widely used as dental restorative materials. A fundamentalknowledge and understanding of the behavior of these materials in the oral cavity is essential to improve theirproperties and performance. The goal of this study was to measure water sorption of four composite resinscontaining different filler and resin matrix contents.Materials and method: Resin composite specimens giomer (Beautifil II) Filtek™ P90, Filtek™ Z350 XT, and Tetric NCeramwere prepared in a cylindrical mould of 3mm thickness and 6mm diameter (n=10) and light cured . Allspecimens placed in silica-gel desiccators at 37˚C for seven days, a constant weight was obtained. All samples wereimmersed in deionized distilled water at 37˚C and weighed at suitable time interval once a week for 30 days. Watersorption was calculated based on ISO 4049. Data were subjected to student t- test.Results: Silorane and Giomer composites showed the lowest values of water sorption, while Z350 and Tetric N-Ceramdisplayed the highest values at a period of 4 weeks.Conclusion: Each resin- matrix composite varied in water sorption which may affect clinical service. The attainedwater sorption values are mainly influenced by the generic type of material and variations occurring betweenmaterials of the same type may result from differences in resin matrix compositions


Article
Assessing The Radiopacity of Three Resin Composite Materials Using a Digital Radiography Technique

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Abstract

Background: Radiopacity is one of the prerequisites for dental materials, especially for composite restorations. It's essential for easy detection of secondary dental caries as well as observation of the radiographic interface between the materials and tooth structure. The aim of this study to assess the difference in radiopacity of different resin composites using a digital x-ray system.Materials and methods: Ten specimens (6mm diameter and 1mm thickness) of three types of composite resins (Evetric, Estelite Sigma Quick,and G-aenial) were fabricated using Teflon mold. The radiopacity was assessed using dental radiography equipment in combination with a phosphor plate digital system and a grey scale value aluminum step wedge with thickness varying from 1mm to 10mm in steps of 1mm each. The tested materials were radiographed, we used Image J software, on a computer screen to evaluate the degree of radiopacity for each individual material and compare with the aluminum step wedge. Radiopacity was expressed in mm of equivalent aluminum step wedge. Analysis of varience (ANOVA) and Least Significant Difference (LSD) were used to investigate the significance of differences among the tested groups.Results: Statistical analysis showed highly significant difference among the tested groups (p≤0.01). Amongst, G-aenial composite shows the most radiopaque and it is above or equivalent to that of enamel, while Estelite Sigma Quick composite has the lowest radiopacity value and is equivalent to that of dentin.Conclusion: In line with previous studies, and within the limitation of our study, considerable variations in radiopacity values were found among materials depending on the radiopaque elements incorporated into the matrix. All composite materials tested complied with the ISO 4049 standard

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