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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
Effect of the addition of bio-polymer lignin on the Transverse and Impact strength of the autopolymerizing acrylic resin.

Authors: Basima M.A. Hussein باسمة محمد --- Thikra I. Hamad ذكرى حمد --- Intisar J. Ismail انتصار جاسم
Journal: Journal of the Faculty of Medicine مجلة كلية الطب ISSN: 00419419 Year: 2010 Volume: 52 Issue: 3 Pages: 359-363
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Acrylic resin dentures are susceptible to fracture; it is unresolved problem in prosthodontics. The repair procedure should be simple, strong, and accurate. This study evaluated the transverse and impact strength of autopolymerizing acrylic resin, the repair material was modified with kraft lignin as a new enforcement material and compared with the commercially available self cured acrylic resin. Materials and Methods: The addition of kraft lignin to the acrylic resin were done in percentages of 0.25%, 0.5%, 0.75%, 1.0%, 1.25%, and 1.5% (wt%). Seventy specimens were made according to the ADA specification No 12 for transverse strength using three point bending test and Impact strength test was conducted following the procedure given by the ISO 179 with Charpy Type Impact testing instrument.Results: Mean transverse strength of experimental specimens where increased only in 0.25wt% addition of lignin (61.3400 Mpa) then results tend to decrease, and no statistical differences found between the control and any one of the modified groups. The impact strength increased more than the control in the groups 0.25, 0.50, 0.75,and 1.0wt%,13.9700, 15.5900, 35.2100, 33.6900 Kj/m2 respectively, then has been decreased at 1.50wt% until reach value of the control (9.2525 Kj/m2).Highly significant difference was found at 0.5, 0.75 and 1.0wt% (p<0.05).Conclusions: The autopolymerizing acrylic resin exhibited significantly higher impact strength as a result of addition the biopolymer lignin. The transverse strength of the modified specimens was decreased after increasing the weight percent addition of lignin.Key words: Autopolymerizing acrylic resin, KL (kraft lignin), transverse strength, impact strength


Article
Effect of Incorporation of Silver Nitrate on Transverse Strength and Impact Strength of Autopolymerizing Acrylic Resin

Author: Intisar Kadhum Farhood
Journal: Karbala Journal of Medicine مجلة كربلاء الطبية ISSN: 19905483 Year: 2014 Volume: 7 Issue: 2 Pages: 1992-1999
Publisher: Kerbala University جامعة كربلاء

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Abstract

background: Autopolymerizing acrylic resin has multiple uses in dentistry such as, record base, orthodontics appliances, denture repair and other. Thedegree of polymerization of cold cured acrylic resin is not as complete as that achieved using heat cured system which leads to a higher degree of un-reacted residual monomer, which act as a plasticizer which results in high transverse deflection values lowering the transverse strength of the resin.Aim of the study: This study investigated the effect of the addition of different concentrations of silver nitrate (AgNO3) on transverse strength and impact strength of autopolymerzing acrylic resin.Materials and methods: A total of 80 specimens were prepared, 40 specimens were fabricated with dimensions of (64×10×2.5) mm to conduct the transverse strength test while the remaining 40 specimens were fabricated with dimensions of (80×10×4) mm to perform the impact strength test. 10 specimens of each group were fabricated from conventional autopolymerized acrylic resin while the remaining 30 specimens were fabricated from modified autopolymerized acrylic resin. Concentrations of 9.375,15 and 60 ppm of silver nitrate were used to modify the autopolymerized acrylic resin, 10 specimens of each concentration in each group were used.Results: The results of this study showed that the modified autopolytmerized acrylic had non-significant difference in transverse strength values for all concentrations of silver nitrate; while there was a significant difference in impact strength values for (15 and 60 ppm) concentrations of silver nitrate and non-significant difference in impact strength values for (9.375 ppm) concentration of silver nitrate .Conclusions: It can be concluded that the addition of (15 and 60 ppm) concentrations of silver nitrate can improve impact strength of autopolymerizing acrylic resin.

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