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Article
The Effect of Formaldehyde Disinfectant on Compressive Strength of Dental Stone (Type IV)

Authors: Musab Mohamed Ibrahim --- Munther Najeeb Kazanji --- Salwa Hachim Mohammed
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2016 Volume: 16 Issue: 28 Pages: 1-9
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The purpose of this study is to evaluate the effect of 2% formaldehyde on compressive strength of dental stone (type IV), and to evaluate its antibacterial effect. Materials and methods: To study the effect of 2% formaldehyde on compressive strength of dental stone (type IV), ten samples of stone were prepared in cylindrical blocks and divided into two groups, each group contain of (5) samples. First group composed of stone and distilled water as (control group) and the second group composed of stone and (2%) formaldehyde solution. after (1h) the samples were tested for compressive strength using digital compression machine(ALFA Company, Turkey).To study the bacterial effect of formaldehyde 60 stone discs prepared and mixed with formaldehyde 2% divided into 12 group (each group consist of 5 discs) and stored for different intervals between 1-12 days, antibacterial effect against salivary sample for each interval day using disc diffusion test. Results: The statistical analysis of data by analysis of t-test reveals significant different in compressive strength between control group and stone-2% formaldehyde group at (P<0.05). The result showed that second group which contains 2%formaldehydehad higher values compared with control group. Also the results showed that the antibacterial effect of stone-formaldehyde discs continued till 12thday. Conclusions: Adding 2% formaldehyde as chemical disinfectant to dental stone increase the compressive strength in addition of the antibacterial activity of stone - formaldehyde disc continued till 12th day.


Article
The effect of two types of disinfectant on shear bond strength, hardness, roughness of two types of soft liners

Author: Rola W. Abdul-Razaq رولا عبد الرزاق
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 2 Pages: 27-31
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Poor oral hygiene results in accumulation of dental plaque and dental biofilms, especially in elderlywith denture, regular cleaning of the dentures using chemical or physical methods can minimize the risk of(stomatitis) in denture users. The aim of this study was to evaluate the effect of two types of disinfectant on somemechanical properties of two types of soft liners.Materials and methods: 180 specimens from 2 types of soft liners (Mollosile, Viscogel) were prepared and divided into2 major groups, mollosile group, viscogel group for each test and each major group is divided into 3 subgroups, eachsubgroup includes 10 specimens. Hardness and roughness test specimens were consist of two discs, acrylic disc withdimensions(4mm,15mm)thickness, diameter respectively and soft liner disc with dimensions (2mm,15mm) thickness,diameter respectively. For shear bond test, specimens were prepared from two blocks of acrylic measuring (75mm,25mm, 5mm)length, width, depth respectively with stopper (3mm) and handle of (13mm) thickness and soft linermaterial in the space between the two acrylic blocks. All specimens were stored in distilled water for 24 hours at 37Cothen they were immersed into water(control group) , Solo, Chlorhexidine 0.2 % disinfectant (test groups) for 8 hours tosimulate the weekly exposure time of soft liner with disinfectant. A profilometer device was used to measure theroughness property and Shore A for hardness property and Micro-computer controlled electronic universal testingmachine for shear bond property.Results: The results revealed that there was a significant difference in roughness mean values for each soft liner afterimmersed in disinfectant solutions while there was no significant difference in mean values of (hardness, shear bondstrength) for each soft liner after immersed into disinfectant solutions.Conclusion: Disinfectant solutions (SOLO, CHLORHEXIDINE) had no effect on hardness and shear bond strength of softliners (MOLLOSILE, VISCOGEL) while they had effect on surface roughness by decreasing the surface roughness ofthese soft liners which is a favorable condition.


Article
Effects of Different Disinfectant Additives on Compressive Strength of Dental Stone

Authors: Qasim A. Mohammad --- Radhwan H. Hasan --- Sadi Sh. Thiab
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2014 Volume: 22 Issue: 5 Pages: 1686-1695
Publisher: Babylon University جامعة بابل

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Abstract

Purpose: The aim of this study was to analyze the compressive strength of dental stone after incorporating different disinfectant solutions during stone models preparation. Materials and methods: A one hundred eighty die stone type IV cylindrical specimens were prepared with dimensions of 20mm diameter and 40 mm height by adding different disinfectants (Sodium hypochlorite 1% and 0.5%, Chlorhexidine 2% and 1%, glutaraldehyde 2% and 1%, Iodine 4% and 2% and a control group without additives) divided into 18 groups, 10 specimens per each group (each two groups identical of same disinfectant and same concentration). Then one of each two identical groups was tested to evaluate its compressive strength after air drying for 24 hours while the other group tested after 48 hours.Results: Chlorhexidine and glutaraldehyde in both concentrations and drying time as well as sodium hypochlorite 0.5% showed no significant difference in compressive strength compared to control group, and they showed higher values compared to sodium hypochlorite 1%. While Iodine groups in both concentrations and drying times showed the least values among all groups.Conclusions: According to the results of this study, Chlorhexidine and glutaraldehyde 1-2% as well as 0.5% sodium hypochlorite can be added to disinfect die stone casts without affecting their compressive strength, while both sodium hypochlorite at a higher concentration and iodine at any concentration are not recommended to be used for this purpose .

الهدف من هذه الدراسة هو دراسة تأثير اضافة مواد معقمة الى قوالب حجر الأسنان على قوة الكبس لهذه القوالب. تم تحضير نماذج اسطوانية من حجر الأسنان قطر القاعدة 20 ملم وارتفاع 40 ملم وبإضافة ماء كمادة قياسية او مواد معقمة بتراكيز مختلفة (كلورهيكسيدين 2% و 1% ، كلوتارالديهايد 2% و 1% ، هايبوكلوريد الصوديوم 1% و 0.5%، يود 4% و 2%) كان المجموع الكلي للنماذج المستخدمة 180 نموذج وتم توزيعها الى 18 مجموعة بواقع 10 نماذج لكل مجموعة (كل مجموعتين متماثلتين بمادة التعقيم ونسبته المئوية)، ثم تم فحص قوة كبس المجموعة الاولى من كل مجموعتين متماثلتين بعد 24 ساعة تجفيف بتركه معرض للهواء وفحص المجموعة الاخرى بعد 48 ساعة. واظهرت النتائج ان كل من الكلورهيكسيدين وكلوتارالديهايد وكذلك هايبوكلوريد الصوديوم بتركيز 0.5% ليس لها تأثير سلبي على قوة الكبس لحجر الأسنان مقارنة مع المجموعة القياسية بدون المواد المعقمة، وجميعها كانت اقوى من مجموعة هايبوكلوريد الصوديوم 1%. في حين كانت مجموعات اليود وبكلا التركيزين و بأي زمن تجفيف هي الادنى وبشكل معنوي مقارنة بجميع باقي المجموعات. يمكن الاستنتاج من هذه الدراسة انه بالإمكان استخدام الكلورهيكسيدين وكلوتارالديهايد 1-2% وكذلك هايبوكلوريد الصوديوم بتركيز منخفض 0.5% لتعقيم قوالب حجر الأسنان، في حين لا يمكن استخدام هايبوكلوريد الصوديوم بتراكيز اعلى وكذلك اليود بأي تركيز كان لهذا الغرض بسبب تأثيرهم السلبي على قوة الكبس لحجر الاسنان.


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.

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