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Article
Effect of Relining Curing Methods on Some Properties of Acrylic Resin Denture Base (Part II)

Author: Nadira A Hatim
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 2 Pages: 211-220
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To investigate the effect of relining by using two curing methods (water bath, or microwave) on some properties ( surface hardness, color property, residual monomer, and porosity) of relined acrylic resin denture base. Materials and methods: The study was done by preparing 320 samples, divided into two parts, the first part involved studying surface hardness, color property, residual monomer, and porosity of samples representing a denture base cured by water bath curing method, and the samples of second part cured by microwave curing method, then the effect of relining by the two curing methods (water bath, and microwave) were evaluated. Samples with dimensions of 30×15×3 ± 0.03mm for the indentation hardness test, 45×10×2.5mm for the color property test, 20×20×3mm for residual monomer test were prepared in this study. Analysis of variance (ANOVA) and Duncan's multiple range tests were used for statistical analysis. Results: surface hardness of denture base cured by microwave was significantly higher (at P=0.05) than denture base cured by water bath, all the relined samples has sig-nificant higher absorbance, and showed that the elusion of monomer was higher at the 1st day. Conclu-sions: Surface hardness, color property and residual monomer of the acrylic resin denture base were affected by relining. Microwave curing method gave better mechanical, and physical properties of the relined acrylic resin denture base, the amount of residual monomer was less in the microwave curing method. Both curing methods gave samples free from porosities.


Article
The Effect of Surface Treatment on the Transverse and Tensile Bonding Strength of Relined Acrylic Resin Denture Base (Part I)

Author: Nadira A Hatim
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 2 Pages: 202-210
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To investigate the effect of the thickness of relining material, curing method (water bath or mi-crowave), and the surface treatment by methyl methacrylate on transverse and tensile strength of re-lined acrylic resin denture base. Materials and methods: A pilot study was done by preparing 65 sam-ples to evaluate the effect of the thickness of relining material in relation to denture base on the trans-verse strength of acrylic resin denture base, and to study the effect of surface treatment by methyl methacrylate on the transverse strength of acrylic resin denture base. The main study was done by pre-paring 320 samples and divided into two parts to study the mechanical properties of samples represent-ing a denture base cured by water bath and other group cured by microwave curing technique, and then the effect of relining by the two curing methods and the effect of surface treatment were evaluated. Analysis of variance (ANOVA) and Duncan's multiple range tests were used for statistical analysis. Results: of this study showed that the different thickness of relining material in relation to denture base had no significant difference on the transverse strength of the relined denture base. The transverse strength and tensile bonding strength of the relined samples were significantly improved (P=0.05) by monomer surface treatment for 180 seconds. Conclusions: Transverse and tensile strength of the acryl-ic resin denture base were affected by relining. Microwave curing method gave better mechanical properties of the relined acrylic resin denture base.


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

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