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Article
Acrylic denture base repair (Part II): Strength of acrylic denture base cured by four different techniques

Authors: Khidair A Salman --- Mohammed M Sadoon
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2006 Volume: 6 Issue: SpIss Pages: S114-S122
Publisher: Mosul University جامعة الموصل

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Abstract

To investigate the effect of repair techniques, surface treatment, and repair space design (3 mm space and no repair space) on the transverse, and tensile strengths of repaired denture base. Materials and methods: Four hundred and sixteen samples of two brand heat cured acrylic resin were repaired by four different techniques (water bath, microwave, thermo press, and chemically cured acrylic resin), treated and untreated with monomer, and repaired with 3 mm space, or no space at fracture area. The samples were tested to measure transverse, and tensile strengths, of repaired, and intact (control) samples. Results: Showed that transverse strength of acrylic denture base repaired by chemically cured acrylic resin was significantly lower (P<0.001) than that of water bath, microwave and thermo press. Transverse strength of repaired acrylic denture base was significantly improved (P<0.001) by monomer surface treatment for 180 seconds, and no space repair design showed the lowest transverse strength compared to 3 mm space repair design. The tensile strength of acrylic denture base repaired by microwave was significantly higher than that of water bath, thermo press, and chemically cured acrylic resin. Acrylic denture base treated with monomer for 180 seconds showed the highest tensile strength compared to untreated acrylic denture base. Conclusion: Acrylic denture base with 3 mm space and treated with monomer that repaired with microwave and water bath techniques were better than other techniques. The samples repaired by chemically cured acrylic resin without surface treatment showed significantly the lowest mean tensile strength. And microwave repairing technique was more time saving and more clean process than water bath technique


Article
Comparisons the microhardness of different cured acrylic denture base systems after subjected to chemical cleaning solutions

Author: Dr. Hawraa Khalid Aziz, B.D.S, M.Sc.* د. حوراء خالد عزيز
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2013 Volume: 10 Issue: 1 Pages: 77-87
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

In selecting chemical cleaning solutions for dental prostheses, compatibilitybetween them and the type of denture base materials must be considered to avoidadverse effects on the hardness of the acrylic resin in different curing systems. Thisstudy aimed to compare the effect of different disinfectant and denture cleanser on thesurface hardness of the light and heat cured acrylic resin materials. Eighty specimensare made from two different denture base materials. Forty specimens are made oflight cured acrylic and forty specimens are made of heat cured acrylic resin. Eachmaterial is subdivided into four subgroups according to the type of the disinfectant(0.12% chlorhexidine digluconate, 0.5% sodium hypochlorite), the denture cleansers(Corega) and compared to the distilled water as control group. The surface hardnesstest is measured for each specimen to show the effect of each chemical cleaningsolution on the light and heat cured denture base hardness. The results of the presentstudy showed non significant differences in the surface hardness comparing betweenthe two curing systems light and heat cured acrylic resin. Also there are nonsignificant differences in the surface hardness when different disinfectant and denturecleansers have been used in comparison to the distilled water. It was concluded fromthis study that the hardness of acrylic materials is not affected by immersion in anytype of disinfectant and denture cleanser as well as it is found that there is no differentin the hardness of the light cured when compared to the heat cured acrylic denturebase.


Article
Evaluation of Transverse strength, Impact strength and Hardness of Thermosense denture base material and compare the result with heat cure acrylic denture base material (in vitro study)

Author: Dr. Hadeel Adnan Mohsin, B.D.S., M.Sc. * د. هديل عدنان
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2016 Volume: 13 Issue: 1 Pages: 64-69
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Background: Thermosense material is the innovative virtually unbreakable, newmonomer free rigid denture base material easy and quick to polish and availablein 10 colors, suitable to patients unable to accept denture made from materialsthat could result in allergic reactions or other sensitivity problems. This type issuitable for full and partial denture and can be used for rebase and reline jobs.Also suitable for overdenture on implant and for repair.Material and methods: sixty samples were prepared and divided in to two maingroups according to the type of material that used (thermosense denture basematerial and heat cure acrylic denture base material). Each main group weresubdivided in to three subgroups according to the type of test that has used(Hardness, impact strength, and transverse strength). Data were analyzed by onewayanalysis of t-test.Results: for this study the result for three tests; hardness, transverse strength andimpact strength show high significant difference.conclusion: This study showed Thermosense denture base material had higher impactstrength than Heat cure acrylic denture base material but this material had highertransverse strength and hardness than Thermosense denture base material.


Article
Effect of addition ZrO2-Al2O3 nanoparticles mixture on some properties and denture base adaptation of heat cured acrylic resin denture base material

Authors: Ali MA Aljafery --- Basima MAH
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2015 Volume: 27 Issue: 3 Pages: 15-21
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The PMMA polymer denture base materials are low mechanical properties, adaptation of the denturebase to underlying tissue is important for retention and stability of denture. The aim of the study was toevaluate theeffect of mixtureZrO2-Al2O3 nanoparticles on impact strength, transverse strength, hardness, roughness, denture baseadaptation of heat cured acrylic resin denture base material.Materials and methods: One hundred (100) specimens were prepared, the specimens were divided into five groups(20 specimens to each) according to the test type, each group was subdivided in to two subgroups (control andexperimental) each subgroup consist of 10 specimens, the experimental group included mixture of 2% (ZrO2-Al2O3ratio2:1) by weight. Theimpact strength was measured by Charpy's impact testing machine, the transversestrength was measured by Instron testing machine while the hardness was measured byshore D durometer androughness was measured by Profilometer. Denture base adaptation was measured by digital microscope andevaluated by computerized tomography (CT).Results: Highly significant increaseofimpact and transverse strength, non-significant increase ofhardness, significantincrease ofroughness andreduction of denture base adaptation (measured at 3 point A, B and C) occurred inexperimental groupwhen compared to control group. CT evaluation, gap between the denture base and mastercast (control and experimental groups) increased from the anterior to posterior side of palate and from the alveolarridge to the mid palatal line.Conclusion: The polymer nanocomposites had mechanical properties higher than neat PMMA at same time lessdenture base adaptation


Article
Modified Processing Technique for Acrylic Resin Denture Base

Author: Ibrahim H. Alfahdawi ابراهيم حمد مخلف
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2018 Volume: 6 Issue: 1 Pages: 28-32
Publisher: Tikrit University جامعة تكريت

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Abstract

Modified flasking technique for acrylic resin denture base at sandy stage. The uniform denture base plate wax pattern was made on the stone casts with a thickness of 3 mm. For the flow of acrylic on ridge, the necks of teeth were slight grinded from palatal or lingual surfaces toward buccal surface to allow more space. The volume of the definitive casts must be reduced as much as possiblebefore flasked in the lower part of the traditional flasks and fill with dental plaster (class II) covering the buccal, labial, incisal and occlusal surfaces of the teeth to give more support and prevent teeth migration. After curing cycle, the denture bases are carefully deflasked, the excess trimmed and polished the surfaces of the denture. Dentures processed with this procedure provides good retention and esthetic, more hygienic and comfortable for the patient than those processed with the conventional method. Giving more support and prevent teeth migration, comfortable for patient, good esthetic, give fine details of the mold and decreasing of time required for processing and finishing the cured prostheses.


Article
The Effect of Different Types of Separating Medium On Some Physical Properties of Processing Acrylic Denture-base with Two Investment Materials: A comparative Study

Author: Nihad H. Mohammed
Journal: nursing national Iraqi specility المجلة العراقية الوطنية للعلوم التمريضية ISSN: 18122388 Year: 2011 Volume: 24 Issue: 2 Pages: 94-109
Publisher: Baghdad University جامعة بغداد

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Abstract

Objective(s): In the present study, glycerin is used as a substitute for tin-foil and cold mold seal (Alginate mould seal) in the process of curing heat and cold-cure acrylic resin denture base against stone and plaster.Methodology: 60 specimens were prepared from heat-cure acrylic resin and cold-cure acrylic resin denture base. The study includes 12 groups of specimens depending on the type of processing, investment material and type of separating medium that are used in curing process. Each group of them contains 5 specimens for each test. Some of physical properties of the processed acrylic denture base that (water sorption and solubility) have been compared with those processed using tin-foil and tin-foil substitute.Results: The results have shown that tin-foil is still the best separating medium that is used due to the best properties obtained when using tin-foil as a separating medium, while no significant differences have been observed between glycerin and cold mold seal specimens in respect to water sorption and solubility of the testing groups.Recommendations: that glycerin can be considered as a satisfactory separating medium for both heat and cold-cured acrylic denture base resins, especially because it is easy to get, easy to use and cheap.

الهدف: لبيان تأثير تبلمر الراتنج الاكريلي يجب فصل سطح القالب عن سطح الجبس لمنع سائل الراتنجي الاكريلي من اختراق الجبس من ناحية ودخول الماء الموجود في الجبس من التسرب إلى الراتنج الاكريلي من ناحية أخرى وكذلك للتقليل من الخشونة الموجودة على أسطح قوالب الجبس التي يمكن أن تخترق وتلتصق إلى قاعدة الطقم الاكرليكي وبالتالي توثر سلباً على قوة الطقم الاكريلي وتسبب له الكثير من الخدش والتكسر. ولتفادي ولمنع مثل هذا الالتصاق، يجب استعمال مادة عازلة جيدة والمعتاد هو استعمال رقائق القصدير المعدنية التي تعدّ من أحسن أنواع المواد العازلة في مجال صناعة الأسنان ولكن لصعوبة استعمالها، تمّ استعمال البديل وهو الجليسيرين وكبديل صوديوم ختم القالب وتمّ إجراء مقارنة بين هده الأنواع في هده الدراسة.المنهجيـة: أخذت (60) عيّنة موزعة على مجموعتين رئيستين حسب عملية الطبخ (المعالجة) الراتنج الاكريلي المعالج ذاتياً وحرارياً مع مادة الجبس. قسمت بالتالي إلى (5) عينات بالإعتماد على نوع المواد العازلة المستعملة ونوع مادة الجبس وتمّ قياس الصفات الفيزيائية وهي قابلية الامتصاص وقابلية الذوبان.النتائـج: أظهرت النتائج أنّ رقائق القصدير أثبتت فعاليتها العالية وأنها الأفضل كمادة عازلة. بينما الجليسيرين وبديل صوديوم ختم القالب لم يكن بينهما أي فروقات إحصائية معنوية ملحوظة بقياس قابلية الذوبان والامتصاص.التوصيات : أولاً تعدّ مادة رقائق القصدير هي الأفضل كمادة عازلة فيما يتعلق بقابلية الامتصاص والذوبان لمادة الراتنج الاكريلكي وثانياً إمكانية استعمال الجليسيرين كمادة عازلة تعطي نتائج جيدة ومقنعة وذلك لسهولة الحصول عليها وتوفرها.


Article
Evaluation of the tensile bond strengths of heat cure acrylic and Valplast with silicone self cure soft liner

Author: Ali J. Abdulsahib علي عبد الصاحب
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: special issue 2 Pages: 5-9
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Soft lining materials have a key role in modern prosthodontics because of their capability of restoringhealth of inflamed and distorted mucosa. Gradual changes of oral tissues require that complete or partial denturesbe relined to improve their adaptation to the supporting tissue. This study aimed to evaluate the tensile bondstrength of heat cure acrylic and Valplast denture base materials to silicone self-cure soft lining material stored inartificial saliva.Materials and method: Two types of self cured silicone soft lining material (one with prime the other without prime oradhesive) applied to polymethylmethacrylate and injection-molded nylon denture base materials for tensile bondstrength testing using Instron machine.Results: The comparison between all test groups after (48) hours immersion in artificial saliva were highly significantly different fromeach other except for the comparison between groups PSP and VSP in which theirmeans were non-significant. After (12) weeks,the comparison between all test groupswere highly significantly different fromeach otherwhen compared statistically.Conclusion: This study indicated that prime (adhesive) increase the bond strength of the silicone soft lining materialswith denture base materials. Silicone soft lining materials are affected by artificial saliva storage


Article
Evaluation the effect of nano-fillers (TiO2, AL2O3, SiO2) addition on glass transition temperature, E-Moudulus and coefficient of thermal expansion of acrylic denture base material

Author: Ihab N. Safi ايهاب نبيل صافي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 1 Pages: 37-41
Publisher: Baghdad University جامعة بغداد

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Background: The PMMA polymer denture base materials are low in thermal and strength properties. The aim of the study was to investigate the change in glass transition temperature, E-Moudulus and coefficient of thermal expansion of acrylic denture base material by addition of Al2O3, TiO2 and SiO2nano-fillers in 5% by weight.Materials and methods: The type of polymerization is free radical bulk polymerization. one hundred twenty (120) specimens were prepared , the specimens were divided into four groups according to the material had been added (one control and three for Al2O3, TiO2 and SiO2nanocomposite) each group was subdivided in to three groups according to the test had been done on it, the degree of transition (Tg) was measured by The differential scanning calorimeter (DSC), E-Modulus and coefficient of thermal expansion and contraction was measured by Thermo Mechanical Analyzer (TMA) .Each sample was tested at different temperatures (30,40,50,60,70C°).Results: Highly significant decrease in coefficient thermal expansion and contraction and in E-Modulus occurred in acrylic incorporated with Al2O3, TiO2 and SiO2 nano-fillers in 5% by weight when compared to control group. For glass transition temperature a significant increase had occurred with the addition of nanofillers at 5% when compared to control group.Conclusion: The results showed that the polymer nanocomposites possess material properties different from that of unmodified PMMA, nanocomposite has thermal and mechanical stability more than heat neat PMMA

الخلفية : البوليمر بدلة المواد الأساسية PMMA منخفضة في الخصائص الحرارية والقوة .. وكان الهدف من الدراسة للتحقيق التغيير في درجة حرارة التحول الزجاجي ، E- Moudulus و معامل التمدد الحراري لل مادة الاكريليك قاعدة أسنان بإضافة AL2O3 ، TIO2 و SIO2 نانو الحشو في 5 ٪ من وزنها .المواد و الأساليب: نوع البلمرة مجانية البلمرة الراديكالية الأكبر . قد أضيفت أعدت مائة وعشرين ) 021 ( العينات ، تم تقسيم العينات إلى أربع مجموعات وفقا للمادة ) عنصر تحكمواحد وثلاثة ل AL2O3 ، TIO2 و SIO2 بمركب متناهي في الصغر ( تم تقسيم كل مجموعة إلى ثلاث مجموعات وفقا لاختبار زيارتها تم القيام به على ذلك، تم قياس درجة التحول) تيراغرام ( بواسطة المسعر المسح التفاضلي ) DSC ) ، E معامل و معامل التمدد الحراري والانكماش و تقاس الحرارية محلل الميكانيكية ) - TMA ( . تم اختبار كل عينة فيدرجات حرارة مختلفة ) 01،01،51،01،01 C . ) °النتائج : انخفاض كبير للغاية في معامل التمدد الحراري والانكماش و E معامل وقعت في الاكريليك تدمج مع - AL2O3 ، TIO2 و SIO2 نانو الحشو في 5 ٪ من الوزن مقارنةبالمجموعة الضابطة . ل درجة حرارة التحول الزجاجي زيادة كبيرة حدثت مع إضافة المالئة النانومترية في 5 ٪ مقارنة بالمجموعة الضابطة .الاستنتاج : أظهرت النتائج أن nanocomposites و البوليمر تمتلك خصائص مواد مختلفة عن تلك التي PMMA معدلة ، بمركب متناهي في الصغر لديه الاستقرار الحراري والميكانيكي أكثر من الحرارة PMMA أنيق.


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
Push-out bond strength and apical microleakage of (MTA Plus, Biodentine, and Bioceramic) as apical third filling (An in vitro study)

Authors: Dr. Abeer A. Abass B.D.S. د. عبير عباس --- Prof. Dr. Jamal A. Mehdi B.D.S., M.Sc. دز جمال عزيزىمهدي
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2016 Volume: 13 Issue: 1 Pages: 1-10
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Background: This study was conducted to evaluate the sealing ability of (MTA Plus,Biodentine Bioceramic root repair material) as an apical third filling by using(Push-out bond strength test, apical microleakage test).Materials and methods: Sixty straight palatal roots of the maxillary first molars teethwere used in this study, the roots were instrumented by using crown downtechnique with Protaper universal rotary system, the roots were randomly dividedinto three groups according to the materials used for filling apical third(n=20).Group (1): MTA Plus . Group (2): Biodentine. Group (3): Bioceramicrepair material. For all groups complete obturation with easy & quick obturationsystem was used. After incubation period of three days ten roots for each groupwere embedded in clear acrylic resin and each root sectioned in apical to provideslice 2mm in thickness. The bond strength was measured using computerizeduniversal testing machine. Ten roots remain from each group used for apicalmicroleakage study. The roots submerged in 2% methylene blue for three days.The roots were cleared and the degree of linear dye penetration was measured inmillimeter by stereomicroscope under 40 X magnification with calibrated scaleocular grid. The data were analyzed statistically using ANOVA and LSD test.Results: In push-out bond strength showed the Biodentine has the highest meanvalues (19.687) in comparison with other groups followed by MTA Plus groupwhich the mean value was (19.395), while the BC material group has the lowestmean value (10.977). In microleakage the BC material group has the high meanvalues (0.477) of apical dye penetration in comparison with other groups.Biodentine group has lowest mean values (0.359) of apical dye penetration.Conclusions: The Biodentine higher push-out bond strength and less apicalmicroleakage then other test materials.

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