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Article
The effect of various staining agents on color stability of acrylic denture teeth materials. (In vitro study)

Authors: Farhan Dakhil Salman --- Raya Mohammed Jawad Al- Gaban
Journal: journal of kerbala university مجلة جامعة كربلاء ISSN: 18130410 Year: 2011 Volume: 9 Issue: 1 Pages: 199-210
Publisher: Kerbala University جامعة كربلاء

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Abstract

The aims of this study was to evaluated of effect the color stability of acrylic denture teeth when exposed to common beverages (coffee, tea and cola) with evaluate of change in the different time after [24 hour, 1 week, 2 weeks and 1 month] to obtain on high aesthetic of acrylic denture teeth.The color stability of acrylic denture teeth is very important factor influencing consumer's acceptability of the aesthetic. The stain solution is effecting the teeth when immersing for long time that replacement of natural color of acrylic teeth, additives has contributed in increasing the color change which result unacceptable of prosthodontic the acrylic denture teeth. In present study (128) samples were immersed into three staining drinks (coffee, tea and cola) as test groups and distilled water as a control group. Color stability measurements of teeth were performed by using a spectrophotometer device. The Color change values were determined after [24 hours, 1 week, 2 weeks and 1 month] of immersion.The Result of the Color stability variable analysis differences were used ANOVA and LSD. The color stability of all denture teeth was a high significant difference (p< 0.01) affected by the immersion of stain solution period. Cola was found to be the most the color change of the denture teeth because that the composition of the cola is the phosphoric acid which lead to scratch of the enemal surface of the denture teeth, also pure agent- materials among the solutions tested (p<0.01). It was concluded that acrylic denture teeth exposed to higher degree of color change and that depended on the amount of color change in each group that increased proportionally with time.

الهدف من هذه الدراسة تقييم تاثير ثباتية اللون للاسنان الاكريكلية عند غمرها بالسوائل التالية وهي( القهوة، الشاي والكولا)مع تقييم التغير في الاوقات المختلفة وهي( 24 ساعة، اسبوع واحد، اسبوعين والشهر واحد) للحصول على اعلى جمالية للاسنان الاكريكلية. ثباتية اللون للاسنان الاكريكلية مهمة جدا كعامل مؤثر على جمالية الاسنان، سوائل الصبغات مؤثرة على الاسنان عند غمرها لمدة طويلة وبالتالي تؤدي الى تعويض اللون الطبيعي للاسنان الطبيعية. السوائل تشترك بالزيادة التغير اللون الطبيعي وتعطي تعويضات غير مقبولة للاسنان الاكريكلية.في هذه الدراسة تم استخدام (128) غمرت في ثلاث انواع من السوائل الملونة وهي( القهوة، الشاي والكولا) كمجاميع للفحص وبالاضافة الى المجموعة القياسية وهو الماء المقطر. ثباتية اللون تم قياسه للاسنان الاكريكلية بواسطة جهاز(spectrophotometer). التغير باللون تم قياسه للاوقات التالية وهي( 24 ساعة، اسبوع واحد، اسبوعين والشهر واحد) بعد الغمر بالسوائل المستخدمة في هذه الدراسة.اظهرت النتائج من خلال استخدام المتغيرات المعتمدة في كل الفحوصات ان هناك اختلاف كبير بين المجاميع في التحليل الاحصائي باستخدام الاختبار(ANOVA) و(LSD) ما عدا الكولا وجد بانه اكثر متغير من المحاليل وذلك لانها تتكون من مواد حامضية وهو حامض الفسفوريك التي تؤدي الى تاكل سطح السن وايضا صبغة نقية اكثر من المحاليل الاخرى. يمكن الاستنتاج بانه الاسنان الاكريكلية اكثر عرضة الى تغير اللون ويعتمد كمية تغير اللون في كل مجموعة زيادة بالشكل تناسبي مع زيادة الوقت.


Article
An Evaluation of Olive Oil as a Separating Medium and Its Effect on Some Mechanical Properties of Processed Acrylic Resin Denture Base (A Comparative Study). Part Two

Authors: Akhlas Zaid Al-Ta’ie --- Widad Abdul-Hadi Al-Nakkash وداد عبد الهادي النقاش --- Farhan Dakhil Salman
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2015 Volume: 27 Issue: 4 Pages: 52-61
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: During acrylic resin processing, the mold must be separated from the surface of the gypsum to preventliquid resin from penetrating into the gypsum, and water from the gypsum seeping into the acrylic resin. For manyyears, tin foil was the most acceptable separating medium, and because it's difficult to apply, a tin-foil substitute isused. In this study, olive oil is used as an alternative to tin foil separating medium for first time, and evaluating its effectas a separating medium on some mechanical properties such as (indentation hardness and transverse strength) ofacrylic resins denture base comparing it with those processed using tin-foil and tin foil substitute such as (cold moldseal) separating medium.Materials and Methods: One hundred Twenty four acrylic resins samples (124) were prepared falling in two maingroups: (heat and cold-cured acrylic denture base resins), for each group three types of separating medium wereused and five tests (10 samples) for each test were carried out, and (4) samples for the chemical composition.Results: Tin foil is one of the most satisfactory separating media in getting the best properties when using it as aseparating medium, while, a statistically no-significant difference have been noticed between olive oil and coldmoldseal samples concerning mechanical properties of tested groups. Infrared spectroscopy analysis showed that,no changes were found in the chemical composition of both heat and cold-cured acrylic resins denture base afterusing olive oil as a separating medium.Conclusion:The present study concluded that olive oil may be used as a substitute for tin foil and cold – mold sealseparating medium in processing both heat and cold – cure acrylic resin denture base.


Article
Measuring and comparing the shear bond strength of acrylic resin veneer to nickel –chromium alloy after different metal surface treatments

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Abstract

The bond strength of metal-resin interface of prosthesis is a key factor indetermining the serviceability of that prosthesis. The main objective of this study wasto determine the effect of different surface treatment on the shear bond strength of Ni-Cr alloy (CB-Blando 72 alloy) and heat cured acrylic veneer resin (Ivoclar Co.).Onehundred twenty eight disc shaped samples from base plate wax were prepared, thediameter of disc was (8mm×4.5mm).After casting the metal, the samples werecleaned, finished, and polished by silicon carbide abrasive paper with a grit size(600μm), and then the profilometer was used to determine the surface roughness ofthe samples (Ra) which ranged between (0.09-0.13μm). Then the samples weredivided into 2 categories ,each category contain (64)samples which also weresubdivided into 8 group ,the first category include (A, B, C, D, E, F, G, H) and thesecond category include (At, Bt, Ct, Dt, Et, Ft, Gt, Ht), according to the metal surfacetreatment which include :Group A, At: Received no treatment and serve as control.Group B, Bt: Received chemical treatment using chemical bonding agent (Metalprimer II).Group C, Ct: Received micromechanical treatment using air abrasion with 50μmAl2O3.Group D, Dt: Received micromechanical treatment using air abrasion with 50μmAl2O3 +metal primer IIGroup E, Et : Received micromechanical treatment using air abrasion with110μmAl2O3.Group F, Ft: Received micromechanical / chemical treatment using (airAbrasion110μm Al2O3 + metal primer II application).Group G ,Gt: Received micromechanical treatment using air abrasion 250μm Al2O3.Group H, Ht: Received micromechanical /chemical treatment using (air abrasion250μm Al2O3 +metal primer II).The acrylic was then prepared as round shape (8mm in diameter and 2mm inthickness) that was placed on the metal surface treatment; the acrylic was fabricated inthe same conventional way for construction veneer resin.For the specimens in the first category, the specimens were tested under drycondition, while in the second category; the specimens were tested after (24) hoursstorage in water room temperature (37˚C) and (1000 time) thermocycling. The shearbond strength was tested in instron universal testing machine.The results before and after thermocycling showed that the air abrasion with50μm Al2O3 plus metal primer II group gave the highest shear bond values, followedby air abrasion with 110μm Al2O3 plus metal primer II, followed by air abrasion with50μm Al2O3, followed by air abrasion with 250μm Al2O3 plus metal primer II,followed by air abrasion with 110μm Al2O3, followed by air abrasion with 250μm,followed by metal primer II group, and followed by untreated group.Also after thermocycling showead that the micromechanical/chemical treatment(air abrasion with Al2O3+metal primer II) gave the highest and more durable shearbond strength values than other groups.

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Article
Evaluation of olive oil as a separating medium and its effect on some physical properties of processed acrylic resin denture base (A comparative study). Part one

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Abstract

Back ground: During acrylic resin processing, the mold must be separated from the surface of the gypsum to preventliquid resin from penetrating into the gypsum, and water from the gypsum seeping into the acrylic resin. For manyyears, tin foil was the most acceptable separating medium, and because it's difficult to apply, a tin-foil substitute isused. In this study, olive oil is used as an alternative to tin foil separating medium for first time, so the aim of the studywas to evaluate its effect as a separating medium on some physical properties such as (surface roughness, watersorption and solubility) of acrylic resins denture base comparing it with those processed using tin-foil and tin foilsubstitute such as (cold mold seal) separating medium.Materials and methods: One hundred forty two acrylic resins samples (124) were prepared falling in two main groups:[heat and cold-cured acrylic denture base resins ], for each group three types of separating medium were used andfive tests (10 samples) for each test were carried out , and (4) samples for the chemical composition.Result: From the result obtained, tin foil is one of the most satisfactory separating media in getting the best propertieswhen using it as a separating medium, while, a statistically no-significant difference have been noticed betweenolive oil and cold-mold seal samples concerning physical and mechanical properties of tested groups. Infraredspectroscopy analysis showed that, no changes were found in the chemical composition of both heat and coldcuredacrylic resins denture base after using olive oil as a separating medium.Conclusion: Lastly, from the results of this study it may be concluded, that olive oil may be used as a substitute for tinfoil and cold – mold seal separating medium in processing both heat and cold – cure acrylic resin denture base

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