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Article
The Effect of the Thermopress Curing Technique on the Water Sorption and Solubility of the Cold and Heat–Cured Acrylic Resins

Author: Lamia T Rejab
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2008 Volume: 8 Issue: 1 Pages: 11-17
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: This study aims to evaluate the effect of the thermopress curing technique on the water sorption
and solubility of the cold–cured and heat–cured acrylic resins and compared this technique with the
bench curing technique used for the cold–cured resin and with the conventional water bath curing technique
for the heat–cured resin. Materials and Methods: they were to measure the water sorption and
solubility, the specimens were prepared as disks with a dimension according to the ADA Specification
No. 12. So specimens were divided into five groups depending on the type of the resin ( cold and heat–
cured ) methods of curing which were ( thermopress, conventional water bath and bench cure ) and the
time of curing cycle. Specimens were weighed before and after immersion in the distilled water and
after drying with silica gel using an electronic balance to measure the water sorption and solubility.
One way analysis of variance (ANOVA) followed by Duncan , s multiple range test was performed to
determined the significant different between the mean values among the tested groups at (p< 0.05)
level of significance. Results: There is a significant differences between the water sorption and solubility
of resin that cured by the different curing methods and different curing cycle times. The water
sorption and solubility of resin specimens that cured by thermopress have the higher values. Conclusions:
The water sorption and solubility of the cold and heat–cured acrylic resins is affected by the curing
method. The curing under higher pressure produces specimens with lower water sorption and solubility
values.


Article
Effect of the Curing Methods on the Surface Hardness of Different Thickness on Heat–Cured Acrylic Resin

Authors: Luay N Abood --- Lamia T Rejab --- Ahmad M Ali
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 3 Pages: S1-S4
Publisher: Mosul University جامعة الموصل

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Abstract

To evaluate the surface hardness of the heat–cured acrylic resins with two different thicknesses cured by two curing methods conventional water bath and microwave energy. Materials and Methods: Heat–cured acrylic resin was used in this study. Rectangular specimens were prepared with two different thicknesses (3 and 6mm) and cured by two different curing methods, conventional water bath and microwave energy methods. The specimens were divided into two groups according to the curing method and specimens thickness. Forty specimens were prepared, ten specimens for each group. The surface hardness was evaluated with Rock well hardness tester. Mean values wear compared statistically with one way analysis of variance (ANOVA) followed by Duncan' s multiple range test to determine the significant different among the groups at (p<0.05) level of significance. Results: The results showed that there is a highly significant difference of the means value of the surface hardness among the four tested groups. Specimens cured by conventional water bath with 3mm thickness have the highest value in relation to 6mm thickness of specimens cured by microwave energy. Conclusions: The curing method, and specimens thicknesses have a significant effect on the specimens surface hardness value. The specimens that cured by the conventional water bath method have a higher values than that cured by the microwave energy curing method and the thicker specimens have a lower values than the thinner one in both curing methods


Article
Comparing &Evaluating the Effect of Air-Powder Polishing System on the Hot Cure Acrylic Denture Base Material Cured by Different Methods
تقییم تأثیر جھاز التلمیع الھوائي على المادة الأساسیةِ لطقومِ الأسنان المصنوعة من مادة الأكریلیكِ الحارالتي تم بلمرتھا بعدة طرق

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Abstract

This study was designed to evaluate the effects of an air-powder polishing system onthe hot cure acrylic denture base material, which was cured in the water bath and microwavemethod, and comparing it with a conventional dental lathe polishing specimens.Thirty samples were made from the hot cure acrylic resin denture base after beingcured in water bath and microwave oven; all samples are condition and then polished. Thesamples were numbered and divided into two groups (according to the types of curingmethod), each group consists of 15 specimens and sub divided into three subgroups: airflowpolishing in (30 sec.), airflow polishing in (10 sec.) and conventional dental lathe polishing in(2 min.). The average surface roughnesses of the samples have been determined with usingthe profilometer (surface roughness tester) before and after polishing procedures.All samples were weighted by using the precision electronic balance before and afterpolishing procedures to obtain the results. The statistical analysis of the results beforepolishing procedures showed that there were no statistically significant difference in thesurface roughness and weight loss of the hot cure acrylic denture base material for both curingmethods, while after polishing treatment by conventional dental lathe polishing (2 min.) andair-powder polishing (10 sec. and 30 sec.), the statistical analysis of the results showed thatthere were a decrease in the surface roughness and weight loss of the hot cure acrylic resin inthe water bath method more than in the microwave method and the best result shown with 2minutes pumice. The weight loss of the acrylic in the (10 seconds) group polished surfaceswas best for the (30 seconds) group when using an air-powder polishing system. So, it ispreferred when using this polishing technique especially on the microwave cure method andthe air-powder, to be used effectively to polish the acrylic denture base materials using a shortperiod time

الغرض من ھذا البحث كَان لدراسة تأثیرَ نظام التلمیع بإستخدام المسحوقِ الھوائي على المادة الأساسیةِ لطقومِالأسنان المصنوعة من مادة الأكریلیكِ الحار التي عولجتْ في جھاز الحمّامِ المائي وفرن المایكرویفِ ومقارنتھ مَع الطریقةالتقلیدیة للتلمیع بمخرطة الأسنانِ التقلیدیةِ .صُنعت 30 عینة مِنْ مادة الراتنجِ أكریلیكِ الحارة (قاعدة طقمِ الأسنانِ ) بعد المُعَالَجَة في الحمّامِ المائي وفرنالمایكرویف، كُل العینات كَانتْ مكیفة وبعد ذلك تتم عملیة التلمیع.أُعِدّتْ العینات وقُسّمِتْ إلى مجموعتین (طبقاً لنوعِ طرقِ مُعَالَجَة الطبخ)، كُلّ مجموعة شَملتْ 15 نموذجِ، قُسّمتَكل من ھاتین المجموعتین إلى ثلاثة مجموعات فرعیةِ :- 1 تَلمیع التیار الھوائي في ( 10 ثواني).- 2 تَلمیع التیار الھوائي في ( 30 ثانیة).- 3 مخرطة الأسنانِ التقلیدیةِ تُلمّعُ في (دقیقتین).وسجلت القراءات (profilometer) تم فحص سطوح النماذج قبل التلمیع وبعده بواسطة جھاز قیاس الخشونةقبل وبعد اجراء التجربة ثم طرحت للحصول على القراءات التي تمثل مقدار التأثیر الحاصل على النماذج.وُزِنتْ كُلّ العینات بإستعمال المیزانِ الإلكترونيِ الدقیقِ (المیزان الحساس) قَبلَ وَبَعد إجراءاتِ التَلمیع للحُصُولعلى النَتائِجِ .أظھر التحلیلِ الإحصائي للنَتائِجِ بأنھ لیس ھناك إختلاف ھامّ في الخشونة السطحیة للمادة الأساسیةِ لطقومِ الأسنانالأكریلیكِ الحار وتخفیف وزن ھذه المادة قبل إجراءاتِ التَلمیع في طریقةِ الحمّامِ المائي وطریقةَ المایكرویفِ .بعد إجراءاتِ التَلمیع العینات بمخرطةِ الأسنانِ التقلیدیة لمدة دقیقتین، وتلمیع بقیة العینات بالتیار الھوائي لمدة10 ثواني و 30 ثانیة) بنظام المسحوقِ الھوائي، بَیّنَ التحلیلَ الإحصائيَ للنَتائِجِ بأنّ ھناك نقصان في خشونة سطح المادة )وتخفیف في وزن مادة الراتنجِ أكریلیكِ الحارِ في طریقةِ الحمّامِ المائي أكثر مِنْ طریقةِ المایكرویفَ .تَلمیع للخشونة السطحیة للراتنجِ أكریلیكِ الحارِ وتأثیرهِ في تخفیفِ وزن المادِة في ( 10 ثواني) أفضل مِنْ التَلمیعفي ( 30 ثانیة) أثناء استعمال نظام المسحوقِ الھوائي، لذا ینصح بإستعمال وقت قصیر من الزمن عند إستخدام (بیكاربوناتالصودیوم) وخصوصاً بطریقةِ الموجات القصیرة (المایكرویف)، والمسحوقَ الھوائي لتَلمیع موادِ طقمِ أسنان الأكریلیكَالأساسیة


Article
The Effect of Autoclave Processing on Some Properties of Cross-Linked Acrylic Denture Base Material
تاثير المعالجة بالموصدة على بعض خصائص الاكريليك المتشابك المستخدم كقاعدة لطقم الأسنان

Author: Husam Mejbel Khalaf حسام مجبل خلف
Journal: Al-Rafidain University College For Sciences مجلة كلية الرافدين الجامعة للعلوم ISSN: 16816870 Year: 2015 Issue: 36 Pages: 305-325
Publisher: Rafidain University College كلية الرافدين الجامعة

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Abstract

Background: Impact strength, surface hardness, water sorption and solubility are important properties for cross linking acrylic resin as denture base material so it is important to evaluate these properties after autoclave processing.Objectives: The aim of this research is to investigate the effect of different time durations of autoclave processing on some physical and mechanical properties of cross linking acrylic denture base materials.Materials and methods: Heat cured cross link acrylic was the acrylic denture base material included in this study. Total of (108) specimens were prepared. The specimens were grouped into: control group in which acrylic resin processed by conventional water bath processing technique and experimental groups in which acrylic resins processed by autoclave at 121°C, 210 KPa. The experimental groups were divided into group 1 (Fast) for 15 minutes. and group 2 (Slow) for 30minutes to study the effect of the autoclave processing, four tests were conducted: impact strength (Charpy tester), surface hardness (shore D), and water sorption and solubility test.Result: The results were analyzed by ANOVA. There were no significant differences between the results of the processing techniques regarding impact, hardness, and water sorption and solubility tests.Conclusions: The autoclave processing technique might also be a good alternative to the conventional water bath processing technique regardless to the cycle of autoclave processing either fast or slow.

قوة الصدمة، وصلادة السطح، وامتصاص الماء والذوبان هي من الخصائص الهامة للاكريليك المتشابك كمادة قاعدة طقم الأسنان لذلك من المهم تقييم هذه الخصائص بعد المعالجة بالموصدة.الهدف من هذا البحث: هو دراسة تأثير فترات زمنية مختلفة من معالجة المُوصَدة على بعض الخصائص الميكانيكية والفيزيائية للاكريليك المتشابك كمادة قاعدة طقم الأسنان.المواد والطرق: تم استعمال الاكريليك المتشابك المعالج حراريا في هذه الدراسة. المجموع الكلي للعينات التي تم تحضيرها هو 108. تم تقسيمها الى : مجموعة التحكم وفيها تم معالجة الاكريليك بحوض الماء التقليدي ومجموعات تجريبية تم فيها معالجة الاكريليك بالموصدة عند درجة حرارة 121° وضغط 210 كيلوباسكال. تم تقسيم المجموعات التجريبية الى المجموعة الاولى (المعالجة السريعة) لمدة 15 دقيقة والمجموعة الثانية (المعالجة البطيئة) لمدة 30 دقيقة لدراسة تأثير معالجة الموصدة. أجريت أربعة اختبارات: قوة الصدمة، والصلادة السطحية واختبارامتصاص الماء واختبار الذوبان.النتائج: عدم وجود فروق ذات دلالة إحصائية بين نتائج انواع المعالجة فيما يتعلق بقوة الصدمة، وصلادة السطح، وامتصاص الماء والذوبان.الاستنتاجات: المعالجة بالموصدة قد تكون أيضا بديلا جيدا للمعالجة بحوض الماء التقليدي بغض النظر عن مدة المعالجة سريعة كانت أو بطيئة.

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