research centers


Search results: Found 3

Listing 1 - 3 of 3
Sort by

Article
Evaluation of the effect of addition of polyester fiber on some mechanical properties of heat cure acrylic resin

Authors: Thikra M. Hachim ذكرى هاشم --- Zainab S. Abullah زينب عبد الله --- Yasamin T. Alausi ياسمين الالوسي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: special issue 1 Pages: 23-29
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: This study aimed to evaluate the effect addition of polyester fibers on the some mechanical propertiesof heat cured acrylic resin (implant strength, flexural strength and hardness)Materials and methods: Ninety specimens were used in the study. Thirty specimens were used for impact strengthmeasurements (80mm X 10mm X 4mm) length, width and thickness respectively. The specimens divided into threetest groups (n=10), first group formed from heat cure acrylic resin without fiber reinforcement. Second group wasformed from heat cure acrylic resin was reinforced with 2 mm length polyester fiber and third group was formed fromheat cure acrylic resin reinforced with 4mm length polyester fiber, impact strength measured by impact testingdevice. 30 specimens with (65 mm X 10mm 2.5mm) length, width and thickness respectively were used in 3 groups(n=10) flexural strength test. The flexural strength was measured by using flexural testing device. 30 specimens with(65mm X 10m X 2.5mm) length width and thickness respectively were used for hardness test. The specimens weredivided into 3 group (n=10) as in impact strength and flexural strength.Hardness measured by using (shore D hardness tester TH210).Results: revealed statistically significant increase on impact strength especially on 4mm length when compared tocontrol group. Significant decreases in flexural strength of PMMP. When compared to control group with 4mm lengthfiber reinforcement. Non significant decrease when compared control group with 2mm length fiber reinforcedPMMA. Significant decrease in hardness of PMMA resin after reinforcement with 2mm, 4mm lengths polyester fibers.Conclusions: Strengthening with the polyester fiber decreased the flexural strength and hardness of the resin, butincreased impact strength. Thus when high impact acrylic resins are needed, fiber reinforced resins may be thematerial of choice

الھدف من ھذا البحث لتقییم تاثیر اضافة الیاف البولیستر للاكریلك الحراري على بعض الخواص المیكانیكیة للاكریلك الحراري (مقاومة الصدمة ,قوة الطي,صلادة السطح).استخدم في البحث 90 نموذج وقد قسمت الى 30 نموذج لكل خاصیة , 30 نموذج لقیاس قوة الصدمة بقیاسات ( 80 ملم* 10 ملم* 4ملم) الطول , العرض,السمك بالتتالي النماذج قسمتالى ثلاثة مجموعات (العدد= 10 ) للاختبار المجموعة الاولى شكلت من الاكریلك الحراري بدون اضافة الالیاف ,المجموعة الثانیة شكلت باضافة الالیاف بطول 2ملم,المجموعة الثالثةشكلت باضافة الالیاف بطول 4ملم. مقاومة الصدمة قیست بواسطة جھاز قیاس الصدمة .30 نموذج استخدمت لقیاس قوة الطي بقیاسات ( 65 ملم* 10 ملم* 2,5 ملم)الطول ,العرض,السمك بالتتالي ,قسمت الى ثلاثة مجامیع( العدد= 10 ) لكل مجموعة وتم قیاس قوة الطي بجھازقیاس قوة الطي. 30 نموذج استخدمت لقیاس صلادة السطح بنفس القیاسات المستخدمة لقیاس قوة الطي .عكست النتائج زیادة ملحوظة في مقاومة الصدمة وخاصة بعد اضافة الالیف بطول 4 ملم ونقصان ملحوظ في قوة الطي بعد اضافة الالیف بطول 4ملم مع نقصان غیر ملحوظ بعداضافة الالیاف بطول ال 2ملم. نقصان غیر ملحوظ لكلا الطولین على صلادة السطح. ھذه الدراسة استنتجت ان اضافة الیاف البولستر تقلل من قوة الطي والصلادة ولكن تزید من مقاومةالصدمة ولذلك عندما نرید ان نستخدم الاكریلك الحراري ذو المقاومة العالیة للصدمة نستخدم الاكریلك الحراري المدعم بالیاف البولیستر


Article
Influence of Heating Rates and Residual Monomer on Dimensional Changes of Acrylic Resin Denture Base

Author: Dr.Ghassan A. Al-Taie, BDS, MSC.* د.غسان الطائي
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2008 Volume: 5 Issue: 4 Pages: 393-397
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

Background: Most of spaces between the denture base and master cast produced by shrinkage of the base material during polymerization and by the difference in coefficient of thermal expansion of the cast and acrylic resin. The aim of this study is to evaluate the effect of the different heating rates and the presence of residual monomer on the accuracy different curing denture base by recording the gap space between the cast and the dentureMaterials and methods: 18 maxillary edentulous stone cast were prepared then divided into three main groups, denture bases were constructed. In Group A, using Biostar plates (free of monomer) in the pressure champers. In group B, using short curing cycle while group C, using long curing cycle . The gap space between the cast and denture base was recorded using traveling microscope measuring device.Results: Biostar curing resin (group A) showed significantly the highest dimensional changes among groups (short and long curing resins). There was no significant difference between group B ( short curing resin) and group C (long curing resin). The lowest gap space values were obtained in long curing resin. All samples showed maximum discrepancy in mid palatal reign and minimum dimensional changes at the crest of ridge. Minimum gap space values were shown in the canine reign for record bases cured with short and long curing cycles, while minimum gap space values were shown in the posterior palatal seal for record base cured with Biostar machine.Conclusion: The dimensional changes of record bases mainly depend on the amount of heat applied during processing rather than the amount of residual monomer. Greater distortion was shown in record base processed by Biostar machine (Free of monomer), while the least distortion in record base processed by long curing cycle. All samples showed maximum discrepancy in the mid palatal region and minimum dimensional changes at the crest of ridge.


Article
The effect of addition of hydroxyapatite microscopic fillers on surface roughness and some mechanical properties of heat cured acrylic resin

Author: Zainab Salih Abdullah زينب صالح عبد الله
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2015 Volume: 27 Issue: 3 Pages: 50-54
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: this study aimed to evaluate the effect of addition of hydroxyapatite micro filler in three concentrations(5%, 10%, 15%) on surface roughness, impact strength, flexural strength and hardness.Material and methods: One hundred sixty acrylic samples were used in this study,40 samples were used for eachtest(impact strength ,flexural strength ,hardness and surface roughness).The test group divided into foursubgroups(n=10) for controlgroup,5%,10% ,15%H,A.concentration addition groups .Impact testing device, flexuralstrength testing device, shore hardness tester and profilometer device were used to measure the four tests examinedin this study.Results: the results showed a significant increase in impact strength, hardness in all concentrations added to heatcured acrylic resin, highly significant decrease in flexural strength, a non-significant difference in surface roughnesstest in 5% concentration while there was a significant differences in other two concentration in the same test.Conclusion: the 5% concentration hydroxyapatite addition was the concentration of choice to be used to increasethe mechanical properties (impact strength) of heat cured acrylic resin without increasing the surface roughness ofthe material.

Listing 1 - 3 of 3
Sort by
Narrow your search

Resource type

article (3)


Language

English (3)


Year
From To Submit

2015 (1)

2013 (1)

2008 (1)