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Article
Effect of Microwave Disinfection on Transverse Strength and Hardness of Acrylic Resin Denture Base Materials

Authors: Ghada Y Abdul-Rahman --- Munther N Kazanji --- Alaa' N Al-Saraj
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2011 Volume: 11 Issue: 22 Pages: 284-291
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To evaluate the effect of microwave disinfection on transverse strength and hardness of acrylic resin denture base materials. Materials and methods: The samples were 112 samples (56 heat cured acrylic resin and 56 microwave cured acrylic resin) they were prepared in dimensions of 65± 0.3x10±0.03x2.5 ±0.03 mm (length, width and thickness respectively) for transverse strength test and 30x15x3±0.03 mm (length, width and thickness respectively) for indentation hardness test. The sam-ples were divided into seven disinfection groups; each one contain five samples which were (control, 900 W or 540W for 3min either inside glass flask containing 150 ml of distilled water)or along with glass flask containing 150 ml of distilled water or alone. The collected data were analyzed using analy-sis of variance (one way ANOVA) at P ≤ 0.05 and Duncan's multiple range test. Results: the transverse strength of microwave acrylic resin samples were significantly decreased except samples that disinfect-ed by 540 watt microwave energy for 3 minute with water inside microwave oven. The hardness num-ber for heat cured acrylic denture base showed no significant differences compared to control group while hardness number of microwave acrylic resin were significantly decreased in relation to control group. Conclusions: Transverse strength of microwave acrylic resin that disinfected with microwave was decreased except at 540 watt for 3 minutes with water a side in microwave oven. While heat cured acrylic resin after microwave disinfection was significantly increased compared with the control sam-ple. Rockwell hardness number for microwave acrylic resin significantly decrease in relation to control group; while for heat cured acrylic denture base showed no significancy comparing with the control group.


Article
Transverse strength measurements of repaired acrylic resin modified with different surface treatments

Author: Dr. Firas Abd Kati Al-Shammari, Assisst. Lecturer د. فراس الشمري
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2014 Volume: 11 Issue: 1 Pages: 88-95
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Aim: the purpose of this study was to evaluate the effect of chemical and mechanicalsurface treatments on repaired acrylic resin in terms of transverse strength.Materials and methods: seventy acrylic specimens were fabricated and divided into7 groups according to kind of reinforcement materials. Thesespecimenswere cut inthe mid and a space of 3 mm was created. The repair was done with varioussurface treatments and specimenswere then subjected to loads till fracture. Datawere analysed and compared via ANOVA and Tukey tests.Results: the transverse strength of repaired acrylic resin had been influenced by thetype of surface treatment used.The repaired samples withglass fibers,stainless steelwire and monomerimproved significantly the bond strength than untreated group(P<0.05).Statistically, there were significant differences between control groupand repaired groups (P<0.05); and among all repaired groups (P<0.05) withexception no significant differencesbetween fiber and monomer, and wire andmonomer groups (P > 0.05).Conclusion:A combination of chemical and mechanical treatments has a significanteffect on transverse strengths. The repaired joints with monomer, wire, or glassfibers had significantly improved the strength of repaired acrylic resin.


Article
Comparison of some physical properties of acrylic denture base material cured by water bath and microwave techniques

Author: Radhwan H Hasan
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2003 Volume: 3 Issue: 6 Pages: 143-147
Publisher: Mosul University جامعة الموصل

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Abstract

This study was designed to evaluate the physical properties (porosity and transverse strength) for microwave cured acrylic resin using new Iraqi microwavable flask. For transverse strength test, 20 acrylic samples were prepared with dimensions 65 × 10 + 0.03 × 2.5 mm. Ten samples were processed by conventional water bath technique, while the other 10 samples were prepared by microwave technique using new Iraqi microwavable flask. The transverse strength of the acrylic samples were measured by three–point bending test. For porosity test, 16 acrylic samples were prepared with dimensions 65 × 55 × 2.5 mm. Eight acrylic samples were processed by conventional water bath while the other 8 samples were processed by microwave technique using new Iraqi microwavable flask. Evaluation of porosity occurrence was done using microscope at 20× and 40× magnifications. The results of student’s t–test showed that there are no significant differences ( p > 0.05) in transverse strength for samples cured by water bath and microwave techniques while microscopical examination revealed that all acrylic samples which cured by both techniques were free from porosities. It was concluded that new Iraqi microwavable flask could be successfully used in curing of acrylic denture base material by microwave technique.


Article
Effect of metal oxides on some mechanical properties of clear acrylic specific for artificial eye

Author: Dr. Firas Abd Kati Al-Shammari. * د. فراس عبد كاطع
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2016 Volume: 13 Issue: 1 Pages: 77-84
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Aim: the study was undertaken to assess the effect of various metal oxides on somemechanical properties of acrylic resin.Materials and methods: Two hundred acrylic specimens were constructed in total.There were two tests utilized (transverse and hardness). For each test, there werenine experimental groups according to the type of metal oxides used. Thespecimens without use any of metal oxides were considered as control. Fortransverse test, the specimens were exposed to loads until fracture. For hardnesstest, the specimens were tested; values were obtained. All data were analyzed andcompared using ANOVA and tukey tests.Results: the addition of metal oxides at different concentrations enhanced thetransverse strength of acrylic. Significant differences were statistically foundbetween experimental groups and control group (P<0.001); among experimentalgroups (P<0.001). For hardness test, there was a slight increase in the mean valuesof hardness of clear acrylic as the concentration of metal oxides increases. Nosignificant differences were statistically found among experimental groups(P>0.05); between experimental groups and control group (P>0.05) except therewas significant difference between control and 5% TiO2 group (P<0.05).Conclusion:The incorporation of metal oxides improved the transverse strength andsurface hardness of acrylic resin.


Article
The effect of adding single walled carbon nanotube with different concentrations on mechanical properties of heat cure acrylic denture base material

Author: Rafah Adil Ibrahim رفاه عادل ابراهيم
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2015 Volume: 27 Issue: 3 Pages: 28-32
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The most widely used material for fabrication of denture base is poly methyl methacrylate, despite itspopularity, the main problems associated with it as a denture base material are poor strength particularly underfatigue failure inside the patient mouth, impact failure outside the patient mouth, which are the main causes forfracture of denture, several studies was done to increase mechanical properties of denture base. The present studywas conducted to evaluate and compare the effect of addition single walled carbon nanotubes in differentconcentrations to polymethyl methacrylate on some mechanical properties (surface hardness, surface roughness,impact strength and transverse strength).Materials and methods: Forty eight samples were prepared for pilot study divided into four groups according to theconcentrations of singled walled carbon nanotubes ( 0%, 0.5%, 1% & 1.5%) added to heat cure acrylic resin , eachgroup was divided into four subgroups according to the tests conducted (Surface hardness , surface roughness,impact strength and transverse strength) and the results obtained were evaluated to determine the concentrationof singled walled carbon nanotubes (SWCNTS) that improve the mechanical properties of heat cure acrylic resin tobe used to complete our study, so another 80 samples were made divided into two main groups (0% SWCNTS ascontrol group) and (1.5% SWCNTS test group) and all the tests were done again.Results: Impact strength and transverse strength were significantly increased after adding 1.5% SWCNTS While surfacehardness was significantly decreased and surface roughness was non-significantly affected when compared withcontrol group.Conclusions: Impact strength and transverse strength of hot cure acrylic resin reinforced with 1.5% SWCNTS weregreatly increased


Article
Effect of Incorporation of Calcium And Fluoride Salts on Transverse Strength of Acrylic Resin

Authors: Hind A. Al-abdali --- Munther N. Kazanji --- Gadah A. Taqa
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2015 Volume: 15 Issue: 30 Pages: 362-368
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The aims of this investigation were to determine the effect of incorporation of CaCO3 from egg shell and Fluoride salt NaF in different concentrations on transverse strength of RESPAL® NF(VEIN 24) heat cured acrylic resin denture base. Materials and Methods: 21 samples of heat cured acrylic resin were prepared, divided it’s into 7 groups; the 1st group Control HCAR , the 2nd group HCAR mixed with 2.5% CaCO3, the 3rd group HCAR mixed with 5% CaCO3, the 4th group HCAR mixed with 10% CaCO3 and the 5th group HCAR mixed with 2.5% NaF, the 6th group HCAR mixed with 5% NaF, the 7th group HCAR mixed with 10% NaF . The samples were tested after 48 hours from preparation for transverse strength test. Results: One way ANOVA and Duncan Multiple Analysis rang test were used and showed significant differences in the transverse strength between the two groups (CaCo3 and NaF), and significant differences between control and CaCo3 while no significance between control and NaF groups. Conclusions: It was concluded that adding NaF to HCAR led to an increase in strength of denture base and significant decrease in strength when adding CaCO3 to HCAR .This was within acceptable range of American Dental Association specification no.12 ,1975.


Article
Reinforced Microwave - Cured Acrylic Resin Denture Base Material with Glass Fibers

Authors: Mohammed A Abdulla --- Radhwan H. Hasan
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2010 Volume: 10 Issue: 20 Pages: 314-321
Publisher: Mosul University جامعة الموصل

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Abstract

AIMS: To evaluation the Effect of adding glass fibers on the transverse strength and the levels of the residual monomer of specially formulated acrylic resin to be cured by microwave and heat cured acryl-ic resin denture base materials. MATERIALS AND METHODS: The materials were used in this study heat cured acrylic resin and microwave cured acrylic resin which is formulated to be cured by microwave energy( Acronacrylic resin). Thirty two samples were prepared for transverse strength test and divided into the following groups Control group (I) heat cured alone, group (II) microwave cured alone, the group (III) heat cured+fibers, group (IV) microwave cured+fibers the transverse strength was evaluated by using an Instron testing machine . Thirty two samples were prepared for residual mono-mer test and divided into four groups water bath and microwave cured with and without glass fibers, the residual monomer was evaluated by using ultraviolet visible spectrophotometer for seven days. RESULTS: Transverse strength test: Statistical Analysis of Variance(ANOVA) shows that there is significant differences at (p>0.0001)among the four groups and Duncan's multiple range test showed that microwave cured + fibers significantly higher transverse strength followed by heat cured +fibers, microwave alone, while heat alone shows significantly lowest transverse strength. Residual monomer test: Analysis of variance(ANOVA) for the four groups from the first day of immersion in water until 7th day shows that there are significant differences between the four groups in the all six days except the 7th day shows that there are no significant differences among the four groups for the level of the residual monomer. CONCLUSIONS: Microwave cured acrylic resin with glass fibers have signifi-cantly higher transverse strength than that of acrylic resin cured by water bath, also microwave cured acrylic resin have significantly lower residual monomer content from the 1st day of immersion when compared to that of water bath which show the same level of residual monomer at the 7th day of im-mersion


Article
The study aims to evaluate the effect of some commercially available natural products (soda+ vinegar, soda +thymol , saturated salt solution) in relation to the commercial denture cleansers (Protifex) ,on surface roughness and hardness dimensional accuracy of acrylic denture base materials. one hundred samples were prepared from heat activated acrylic resin denture base material, they are (1cm*1cm*2mm length, width and thickness respectively). After that, half of the samples for each group were immersed for ½ hr per day in the denture cleanser, the other half of the samples immersed for 8 hr per day in the denture cleanser through one month. The denture cleansers used are three solutions prepared freshly everyday for immersion of the samples. The surface roughness of the samples were tested by using Stylus profilometer(Talysurf 10, England), while the hardness of the samples were tested by using Rockwell hardness tester (Wolpert, Germany), the mean is taken for each group and evaluated by using one way analysis of variance test, Dunnet T-test to compare the groups. The results demonstrated that there were no significant differences in the surface roughness and hardness, but with significant difference between treats of length of acrylic resin denture base material and duration of immersion at (P=0.05). All the prepared natural solutions would be accepted in relation to effect on surface roughness , dimensional accuracy, and hardness of acrylic denture base material.

Author: Suad G. Al Nakash ساعد النقاش
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2013 Volume: 2 Issue: 2 Pages: 137-144
Publisher: Tikrit University جامعة تكريت

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Abstract

Autopolymerizing acrylic resin is one of the most frequently used materials in dentistry, but it has relatively poor mechanical properties This study investigated the effect of the addition of poly vinyl pyrrolidone on transverse strength, impact strength and surface roughness of autopolymerzing acrylic resin. A total of 60 specimens were prepared, 30 specimens of each conventional and modified autoplymerizing acrylic.20 specimens of each groups were fabricated with dimensions of (64×10×2.5) mm to conduct the transverse strength and surface roughness tests, while the remaining 10 specimens of each group were fabricated with dimensions of (80×10×4) mm to perform the impact strength test. The results of this study showed that the modified autopolytmerized acrylic had significantly higher transverse strength, and significantly lower surface roughness values while there was no significant differences in impact strength value. It can be concluded that addition of Polyvinylpyrrolidone can improve transverse strength and surface roughness of autopolymerizing acrylic resin.


Article
The effect of thermocycling and different pH of artificial saliva on the impact and transverse strength of heat cure resin reinforced with silanated ZrO2 nano-fillers

Author: Rola W. Abdul-Razaq رولا وليد عبد الرزاق
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: special issue 1 Pages: 12-17
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The aim of this study was to evaluate the effect of thermo cycling and different pH of artificial saliva(neutral, acidic, basic) on impact and transverse strength of heat cure acrylic resin reinforced of with 5% silanatedZrO2 nano fillers.Materials and methods: 120 samples were prepared, 60 samples for impact strength test and another 60 samples fortransverse strength test, for each test, samples were divided into two major groups (before and after thermo cycling),then each of these major groups were further subdivided into 3 subgroups according to the pH of prepared artificialsaliva (neutral, acidic, basic). Charpy impact device was used for impact strength test and Flexural device was usedfor transverse strength test.Result: There was a non-significant difference between the two major groups (before and after thermo cycling). Alsoresults showed that there was a non-significant difference between the subgroups for each major group in referenceto pH of artificial saliva. These results were found in both impact and transverse strength.Conclusion Transverse strength and impact strength of heat cure acrylic resin reinforced with silanated ZrO2nanofillers was not affected by thermocycling and different PH of artificial saliva suggesting improvement in themechanical properties


Article
The effect of addition of untreated and oxygen plasma treated polypropylene fibers on some properties of heat cured acrylic resin

Authors: Waffaa I. Mohammed --- Intisar J. Ismail
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: 4 Pages: 33-38
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The polymethyl methacrylate is the most reliable material for the construction of complete and partialdentures, despite satisfying esthetic demand itsuffered from having unsatisfactory properties like impact strength andtransverse strength.This study was designed to improve the impact strength and transverse strength of heat cure acrylic resin by addinguntreated and oxygen plasma treated polypropylene fibers and investigate the effect of this additive on someproperties of acrylic resin materials.Materials and methods: Untreated and oxygen plasma treated polypropylene fibers was added to PMMA powderby weight 2.5 %. Specimens were constructed and divided into 5 groups according to the using tests; each groupwas subdivided in to 3 subgroups. The tests conducted were impact strength, transverse strength, surface hardness,surface roughness, water sorption and solubility. Data were analyzed by one way analysis of variance (ANOVA) andleast significant differences (LSD).Results: After incorporation of untreated and oxygen plasma treated polypropylene fibers there was a highlysignificant increase in impact strength and surface hardness; while there was a non significant difference intransverse strength. Also the value of water sorption increase significantly but with the limit of ADA specification.Conclusion:Within the limit of this study it can be concluded that the reinforcement with polypropylene fiberseffective method to increase fracture resistance of denture base; while reinforcement with oxygen plasma treatedpolypropylene fibers further increase fracture resistance

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