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Article
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
Microleakage Evaluation of a Silorane-Based and Methacrylate-Based Packable and Nanofill Posterior Composites (in vitro comparative study)

Author: Manhal A. Majeed منهل عبد الرحمن مجيد
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2012 Volume: 1 Issue: 2 Pages: 19-26
Publisher: Tikrit University جامعة تكريت

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Abstract

This study compared in vitro the microleakage of a new low shrink silorane-based posterior composite (Filtek™ P90) and two methacrylate-based composites: a packable posterior composite (Filtek™ P60) and a nanofill composite (Filtek™ Supreme XT) through dye penetration test. Thirty sound human upper premolars were used in this study. Standardized class V cavities were prepared at the buccal surface of each tooth. The teeth were then divided into three groups of ten teeth each: (Group 1: restored with Filtek™ P90, Group 2: restored with Filtek™ P60, and Group 3: restored with Filtek™ Supreme XT). Each composite system was used according to the manufacturer's instructions with their corresponding adhesive systems. The teeth were then thermocycled, immersed in 1% methylene blue dye for 24 hours at room temperature, embedded in auto-polymerizing acrylic resin and sectioned longitudinally bucco-lingually. Microleakage was evaluated by assessing the linear dye penetration at the tooth/restoration interface occlusally and gingivally. The highest microleakage score occlusally or gingivally was recorded and the results were analyzed statistically using SPSS version 13. The results of this study showed that the silorane-based posterior composite Filtek™ P90 showed significantly less microleakage than the methacrylate-based packable composite (Filtek™ P60) and the nano-filled composite (Filtek™ Supreme XT) when the tooth-restoration interface is located in enamel.


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
Evaluation of the effect of intermediate agents on the shear bond strength of repaired aged silorane resin composite

Authors: Hanaa A. Saleh هناء صالح --- Luma M. Baban لمى بابان
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 4 Pages: 8-13
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The aim of this study was to evaluate the bonding effect of different intermediate agents on the bondstrength of silorane resin composite (Filtek™ P90,3M ESPE) that repaired by either silorane (Filtek™ P90) ormethacrylate based resin composite (Filtek™ Z250,3M ESPE)Materials and Methods: Eighty specimens of resin composite prepared by filling silorane (Filtek™ P90) into a retentivecavity (6mm in diameter and 2mm in depth) of acrylic mold. The composite were polymerized, water stored at 37°Cfor one week. Their surface were finished with medium (violet) super-snap disks then rinsed in ultrasonic cleaner.Repair was performed with either silorane (Filtek™ P90) or methacrylate based composite (Filtek™ Z250) by usingseveral intermediate agents which include (P90 System Adhesive, Adper Scotchbond Multipurpose and Clearfilrepair kit).The shear bond strength (crosshead speed 0.5 mm/min) was measured after an additional water storageof 24 hour.Results: Statistical analysis of data revealed that intermediate agents enhanced the bond strength significantly(p<0.001).The highest shear bond strength were determined for Clearfil repair kit and P90 System Adhesive whichwere significantly higher than the control (p<0.001). Adper Scotchbond Multipurpose enhanced the bond strengthsignificantly than the control but it was significantly lower than the other adhesive systems (p<0.001).Conclusions: The Clearfil™ Repair kit and P90 System Adhesive were the most effective intermediate agents for repairof silorane restoration with both silorane and methacrylate repair materials.Use of Adper Scotchbond Multipurposeresulted in bond strength which is considered clinically inadequate


Article
Effect of curing mode on immediate and post-irradiation depth of cure of a silorane-based and methacrylate- based posterior composites (in vitro comparative study)

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Abstract

Background: Incomplete polymerization of composite restorations compromises the restoration both mechanicallyand biologically. Recently, composite curing lights have been developed that have higher intensities and shortercuring cycles which help speed the resin-based curing. This study was conducted with the aim of evaluating theeffect of conventional and high intensity light curing units on the depth of cure of three different types of compositeresin.Materials and Method: Forty eight cylindrical specimens 4mm in diameter and 8mm in height were prepared fromthree types of composite resin (Filtek™ P60,Tetric EvoCeram and Filtek™ P90) using a two-piece aluminum mold. Halfof the specimens were cured with a QTH for 40 seconds, while the other half of the specimens were cured with theFlashMax P3 high intensity light curing unit for 3 seconds. The cured specimens of each composite type were thensubdivided into three subgroups of eight specimens each according to the aging period prior to curing depthmeasurement (immediate, after 24 hours, or after 7 days). The depth of cure was measured using the scrapingmethod (scratch test).Results: The results of this study showed that Filtek™ P60 showed the highest mean depth of cure, followed by TetricEvoCeram and Filtek™ P90 which showed the lowest curing depth regardless of the curing mode or aging period,and the difference was statistically highly significant (p< 0.01). The results of the study also showed that the specimenscured with the QTH had higher curing depth than those cured with the FlashMax P3 regardless of the composite typeand aging period and the difference was also statistically highly significant (p< 0.01). Concerning the effect of aging,there was an increase in curing depth till 24 hours for Filtek™ P60 and Tetric EvoCeram, while for Filtek™ P90 theincrease in curing depth continued till 7 days.Conclusions: The packable composite Filtek™ P60 showed the highest curing depth as compared with the nanofilledcomposite Tetric EvoCeram and the silorane-based composite Filtek™ P90. However, there was a continuousincrease in curing depth of the silorane-based composite with time. All composite resins cured with the conventionalQTH light curing unit presented higher curing depths than those cured with the FlashMax P3 high intensity light curingunit.


Article
Effect of casein phosphopeptide-amorphous calcium phosphate on surface roughness of a silorane-based and methacrylate-based composite resin (In vitro comparative study)

Author: Baydaa Hussein بيداء حسين
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 3 Pages: 106-112
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: When using a fluoridated agent for caries-preventive intervention, the clinician should be careful not toallow the agent to come into contact with the composite restorations since topically applied fluorides were found toinduce adverse effects on the morphologic characteristics and composition of composite restorations. A newremineralizing agent "MI Paste" and its fluoridated form "MI Paste Plus" based on Recaldent technology (CPP-ACP)were developed. This study was conducted with the aim of assessing the effect of these new remineralizing agentson surface roughness of two types of composite resin materials.Materials and Method: Cylindrical specimens 12mm in diameter and 2mm in height were prepared from two types ofcomposite resin materials: Filtek™ P90 (a silorane-based composite material) and Filtek™ Z350 XT (a methacrylatebasednanofill composite material). Each specimen was cured against a celluloid strip in a specially designedcylindrical mold using a QTH light curing unit for 40 seconds. Forty specimens were prepared for each compositetype and subdivided into four subgroups of ten specimens each: Subgroup 1: without treatment, dry-stored in anincubator at 37ïC for one week (control subgroup), Subgroup 2: without treatment, stored in deionized water in anincubator at 37ïC for one week, Subgroup 3: treated with MI Paste once daily for one week, and Subgroup 4:treated with MI Paste Plus once daily for one week. Surface roughness of the specimens was obtained with a surfaceprofile testing machine, which used the roughness average (Ra) to assess surface changes. Several measurementswere taken for each specimen and the mean value of these measurements on one specimen was regarded as theRa of that specimen. The mean Ra value of each subgroup was then calculated.Results: The results of this study showed statistically non-significant differences among the different subgroups ofFiltek™ P90 composite resin material. Concerning Filtek™ Z350 XT composite resin material, the results showed astatistically highly significant difference in surface roughness between the subgroup stored in deionized water andthe control one, with statistically non-significant difference between the subgroups treated with MI Paste and MIPaste Plus and the control subgroup. Comparison of significance between the corresponding subgroups of bothcomposite types revealed statistically non-significant differences except for subgroup 2 which showed a statisticallysignificant higher surface roughness in Filtek™ Z350 XT than Filtek™ P90.Conclusions: The daily application of the MI Paste and MI Paste Plus for one week had non significant effect onsurface roughness of the silorane-based composite resin material Filtek™ P90. On the other hand, the application ofthese agents caused surface smoothening of the nanofilled methacrylate-based composite resin material Filtek™Z350 XT.


Article
The effect of in office bleaching on surface roughness and micro-hardness of newly developed composite materials (In vitro study)

Authors: Noor S. Nadhum نور ناظم --- Ali H. Al-Khafaji علي حسين الخفاجي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 2 Pages: 24-29
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Alterations in the microhardness and roughness are commonly used to analyze the possible negativeeffects of bleaching products on restorative materials. This in vitro study evaluated the effect of in-office bleaching(SDI pola office +) on the surface roughness and micro-hardness of four newly developed composite materials(Z350XT –nano-filled, Z250XT-nano-hybrid, Z250-mico-hybrid and Silorane-silorane based).Materials and methods: Eighty circular samples with A3 shading were prepared by using Teflon mold 2mm thicknessand 10mm in diameter. 20 samples for each material, 10 samples for base line measurement (surface roughness byusing portable profillometer, and micro-hardness by usingDigital Micro Vickers Hardness Tester), and 10 samples forafter bleaching measurement. The appropriate bleaching procedure was performed on the top surface of testgroups for 90 minutes total bleaching period. Then surface roughness and hardness were tested at the end of theduration. Statistical analysis was carried out using ANOVA, LSD and t-test.Results: There was a highly significant increase in surface roughness of all tested groups after bleaching. There is ahighly significant increase in micro-hardness for Z250, there is decrease in Micro-hardness for siloraneand Z250xt andthere is a non-significant increase in micro-hardness of Z350xt.Conclusion: bleaching has a negative effect on surface roughness of all the tested materials, as surface roughnessincreased after bleaching. Micro-hardness is a material dependent, there is different reaction to bleachingdepending on the resin, load and size of the fillers used in the materials. Nano-filled composite is the material that hasbetter performance than the other tested materials, as it is the material that has the least affection by bleaching

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