scholarly journals Environmental Impacts on the Strength Parameters of Mineral-Acrylic (PMMA/ATH) Facade Panels

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Aleksander Byrdy ◽  
Michał Kołaczkowski
Keyword(s):  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Environmental Influence ◽  
Acrylic Resin ◽  
Strength Parameters ◽  
Climate Conditions ◽  
Acrylic Resins ◽  
Natural Minerals ◽  
Lack Of Information ◽  
Strength Tests

Composite mineral-acrylic panels consist in 80% of natural minerals produced from bauxite (aluminium hydroxides (ATH)) and in 20% from acrylic resin (polymethyl methacrylate (PMMA)). This material due to high usability is widely used in interior finishes. Recently, the mineral-acrylic panels have been used as external claddings of buildings. So far, there are several dozen elevations realized worldwide. Due to the variability of the strength parameters of PMMA acrylic resins depending on the environmental influence, a number of tests on samples of mineral-acrylic panels to verify their suitability for use in climate conditions in Central Europe were performed. The studies determined the change of the material parameters after being subjected to aging process in conditions of high temperature, high relative humidity, freeze-thaw cycles, and UV radiation. In the studies parameters such as flexural strength and modulus of elasticity were measured at a reference temperature of 23°C. In raised and lowered temperatures only the tensile strength tests were conducted. Due to the lack of information in the available literature, the authors carried out tests of the temperature influence on the PMMA/ATH composite modulus of elasticity and flexural strength which is crucial in designing process.

scholarly journals Effect of microwave disinfection on physical and mechanical properties of acrylic resins

2008 ◽  
Vol 19 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Rafael Leonardo Xediek Consant ◽  
Erica Brenoe Vieira ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
João Neudenir Arioli-Filho
Keyword(s):  
Flexural Strength ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Acrylic Resins ◽  
Strength Tests ◽  
The Impact

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.

scholarly journals Antimicrobial properties, anti-virulence activities, and physico-mechanical characteristics of orthodontic adhesive containing C-phycocyanin: a promising application of natural products

Folia Medica ◽  
2021 ◽  
Vol 63 (1) ◽  
pp. 113-121
Author(s):  
Maryam Pourhajibagher ◽  
Abbas Bahador
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Antimicrobial Properties ◽  
Acrylic Resin ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Microbial Biofilms ◽  
Growth Inhibition Zone ◽  
Orthodontic Adhesives ◽  
Acrylic Resins

Introduction: Antimicrobial orthodontic adhesives aim to reduce enamel demineralization, white spot lesions, and incipient tooth decay around bonded orthodontic brackets, but they should not imperil its mechanical properties.  Aim: To evaluate the antimicrobial and physico-mechanical properties of acrylic containing different concentrations of C-phycocyanin on Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Materials and methods: The mechanical properties of acrylic resins were measured by flexural strength test after preparation of acrylic resin samples with concentrations of 1%, 2%, 5%, 7.5%, and 10% of C-phycocyanin. Then we evaluated the antimicrobial effects of acrylic resin containing the maximum concentration of C-phycocyanin with clinically acceptable flexural strength and the changes in expression of virulence factors. Results: The highest and lowest means of flexural strength were obtained in acrylic resins containing 0% and 10% concentrations of C-phycocyanin at 50.2±4.5 and 30.1±3.3 MPa, respectively. Adding 1%, 2%, and 5% of C-phycocyanin showed no significant decrease in flexural strength (p>0.05). The maximum mean diameter of the growth inhibition zone was observed around discs containing 5% of C-phycocyanin. Until day 30 of the study, no microbial biofilms were formed on any acrylic disc. Only microbial biofilms of C. albicans were able to form on discs containing 5% of C-phycocyanin at 90 days. 5% C-phycocyanin could significantly decrease the expression levels of gtfB, hsp16, and ALS9 6.1-, 7.3-, and 3.9-fold, respectively. Conclusions: It can be concluded that the most acceptable concentration of C-phycocyanin in acrylic resin is 5% based on the results of flexural strength tests and antimicrobial activities of acrylic resin containing various concentrations of C-phycocyanin.

scholarly journals Polytetrafluorethylene added to acrylic resins: mechanical properties

2010 ◽  
Vol 21 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Fabiana Gouveia Straioto ◽  
Antonio Pedro Ricomini Filho ◽  
Alfredo Júlio Fernandes Neto ◽  
Altair Antoninha Del Bel Cury
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Peak Load ◽  
Surface Hardness ◽  
Acrylic Resin ◽  
Denture Base ◽  
Standard Data ◽  
Acrylic Resins

The addition of different polymers, such as polytetrafluorethylene (PTFE), to denture base resins could be an option to modify acrylic resin mechanical properties. This study evaluated the surface hardness, impact and flexural strength, flexural modulus and peak load of 2 acrylic resins, one subjected to a long and another subjected to a short polymerization cycle, which were prepared with or without the addition of 2% PTFE. Four groups were formed according to the polymerization cycle and addition or not of PTFE. Forty specimens were prepared for each test (10 per group) with the following dimensions: hardness (30 mm diameter x 5 mm thick), impact strength (50 x 6 x 4 mm) and flexural strength (64 x 10 x 3.3 mm) test. The results of the flexural strength test allowed calculating flexural modulus and peak of load values. All tests were performed in accordance with the ISO 1567:1999 standard. Data were analyzed statistically by ANOVA and Tukey's test with the level of significance set at 5%. No statistically significant differences (p>0.05) were found for surface hardness. Flexural strength, impact strength and peak load were significantly higher (p<0.05) for resins without added PTFE. The flexural modulus of the acrylic resin with incorporated 2% PTFE polymerized by long cycle was significantly higher (p<0.05) than that of the other resins. Within the limits of this study, it may be concluded that the addition of PTFE did not improve the mechanical properties of the evaluated acrylic resins.

scholarly journals Variations in Flexural Strength of Heat-polymerized Acrylic Resin after the Usage of Denture Cleansers

2016 ◽  
Vol 17 (4) ◽  
pp. 322-326 ◽  
Author(s):  
M Kalavathi ◽  
Mallikarjuna Ragher ◽  
G Vinayakumar ◽  
Sanketsopan Patil ◽  
Aishwarya Chatterjee ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Testing Machine ◽  
Peak Load ◽  
Acrylic Resin ◽  
Control Group ◽  
Denture Base ◽  
Acrylic Resins ◽  
Significant Difference ◽  
Base Resin ◽  
Denture Cleansers

ABSTRACT Objective The objective of this study was to evaluate and compare changes in the flexural strength of heat-cured denture base resins when treated using denture cleansers. Study design A total of 40 specimens with dimension 65 mm length, 10 mm width, and 3 mm thickness were prepared as per ISO 1567 specification. A total of 10 specimens were immersed in distilled water to be used as control. Of the remaining 30 samples, 10 were treated with Clinsodent, 10 with VI-Clean, and 10 with Clanden denture cleansers. Specimens in each group were subjected to three-point flexural load in universal testing machine at a cross-head speed of 5 mm/min. The peak load (N) was recorded and flexural strength was calculated. The findings were analyzed using Kruskal–Wallis analysis of variance and Mann–Whitney test. Results Heat-cured denture base resin selected for this study showed significant difference in flexural strength after immersion in denture cleansers Clinsodent, VI-Clean, and Clanden solutions, when compared with the control group. Conclusion Findings of this study showed that denture cleansers altered the flexural strength of heat polymerized acrylic resins that endured soaking cycles which simulated 180 days of use. Hence, denture cleansers should be used with caution, once a day after brushing the dentures. It is advisable for patients to follow the manufacturer's instructions. How to cite this article Ragher M, Vinayakumar G, Patil S, Chatterjee A, Mallikarjuna DM, Dandekeri S, Swetha V, Pradeep MR. Variations in Flexural Strength of Heat-polymerized Acrylic Resin after the Usage of Denture Cleansers. J Contemp Dent Pract 2016;17(4):322-326.

scholarly journals Incorporation of Chitosan Nanoparticles into a Cold-Cure Orthodontic Acrylic Resin: Effects on Mechanical Properties

Biomimetics ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 7
Author(s):  
Mostafa Shahabi ◽  
Sorour Movahedi Fazel ◽  
Abdolrasoul Rangrazi
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Impact Strength ◽  
Flexural Strength ◽  
Chitosan Nanoparticles ◽  
Antimicrobial Properties ◽  
Acrylic Resin ◽  
Orthodontic Appliances ◽  
Negative Effects ◽  
Acrylic Resins

Improvement of the antibacterial properties of acrylic resins, used in the construction of removable orthodontic appliances, is an important strategy to reduce the incidence of caries and oral diseases in orthodontic treatments. The addition of antimicrobial agents to acrylic resins is one of the effective methods to enhance the antimicrobial properties of these materials. However, one main concern is that modification of acrylic resin has negative effects on its mechanical properties. Recently, chitosan nanoparticles (NPs), as biocompatible and biodegradable polysaccharides with remarkable antimicrobial properties, have been used in different areas of dentistry and medicine. This study aimed to investigate the effects of adding chitosan NPs on the mechanical properties of a cold-cure orthodontic acrylic resin. The chitosan NPs were added to the acrylic resin in various weight percentages: 0% (control), 0.5%, 1%, 2%, and 4%. The flexural strength, compressive strength, Vickers microhardness, and impact strength measurements were performed for all five groups. The results showed that adding up to 1% (w/w) chitosan NPs to an acrylic resin had no significant negative effects on its flexural strength and compressive strength, while it decreased these parameters at weight percentages of 2% and 4% (w/w). The results also revealed that modification of acrylic resin with chitosan NPs up to 4% had no significant negative effects on the microhardness and impact strength of acrylic resin. In conclusion, the addition of chitosan NPs up to 1% (w/w) had no significant negative effects on the mechanical properties of cold-cure acrylic resin.

scholarly journals Effect of adding zinc oxide nanoparticles supported in 4A zeolite on antibacterial properties and flexural strength of self-curing acrylic resin used in removable orthodontic appliances

2021 ◽  
Vol 43 (3) ◽  
pp. 274-282
Author(s):  
Mahdiyeh Esmaeilzadeh ◽  
Baharak Divband ◽  
Fatemeh Yeganeh Sefidan ◽  
Mona Gholami ◽  
Mojgan Kachoei
Keyword(s):  
Flexural Strength ◽  
Antibacterial Properties ◽  
Acrylic Resin ◽  
Test Method ◽  
Bending Test ◽  
Orthodontic Appliances ◽  
X Ray ◽  
Acrylic Resins ◽  
4A Zeolite ◽  
Base Plates

Background: Self-curing acrylic resins, mainly composed of Polymethyl Methacrylate (PMMA), are widely used to manufacture removable orthodontic appliances. Self-curing acrylic resins have higher porosity than heat-curing acrylic resins leading to a susceptible place for microbial plaque colonization. Due to some of these microorganisms' activities, a very unpleasant odor is emitted from orthodontic base plates, which has adverse effects on patients' cooperation. This study aimed to investigate the antimicrobial properties of cold-curing PMMA acrylic resin containing ZnO nanoparticles supported in 4A zeolite and evaluating its mechanical properties. Methods: The synthesized nanocomposite ZnO/4A zeolite was added to SR Triplex® Cold orthodontic self-curing acrylic resin powder with 2wt% and 4wt% concentrations. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), energy dispersive X-ray (EDX), MAP analysis, and Dynamic light scattering (DLS) were performed to investigate the sample's characteristics. Direct test method was used to assess the antibacterial properties of the fabricated acrylic samples against three bacterial strains Streptococcus mutans, Klebsiella Pnemoniae, and Esherichia coli. Flexural strength was evaluated by a three-point bending test, and One-way ANOVA and Tukey's post hoc test were used for statistical evaluation of data. The p-value of less than 0.05 was considered significant. Results: The addition of ZnO/4A in 2wt% and 4 wt% concentrations lead to more than 99% destruction of colonies in all three types of microorganisms. The mean flexural strength of acrylic specimens containing 2wt% and 4wt% of ZnO/4A significantly lower than the control group. Despite the considerable reduction, all mean values are greater than 50 MPa. Conclusion: The ZnO/4A zeolite nanocomposite due to its potent antibacterial properties and minimal toxicity can reduce the unfavorable odor of orthodontic base plates consequently increases patient cooperation and reaching the desired result. Method: The synthesized nanocomposite ZnO/4A zeolite was added to SR Triplex® Cold orthodontic self-curing acrylic resin powder with 2wt% and 4wt% concentrations. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy(FE-SEM), energy dispersive X-ray (EDX), MAP analysis, and Dynamic light scattering (DLS) were performed to investigate the sample's characteristics. Direct test method was used to assess the antibacterial properties of the fabricated acrylic samples against three bacterial strains Streptococcus mutans, Klebsiella Pnemoniae, and Esherichia coli. Flexural strength was evaluated by a three-point bending test, and One-way ANOVA and Tukey's post hoc test were used for statistical evaluation of data. The p-value of less than 0.05 was considered significant. Results: The addition of ZnO/4A in 2wt% and 4 wt% concentrations lead to more than 99% destruction of colonies in all three types of microorganisms. The mean flexural strength of acrylic specimens containing 2wt% and 4wt% of ZnO/4A significantly lower than the control group. Despite the considerable reduction, all mean values are greater than 50 MPa. Conclusion: The addition of ZnO/4A zeolite nanocomposite due to its potent antibacterial properties and minimal toxicity can reduce the unfavorable odor of orthodontic base plates consequently increases patient cooperation and reaching the desired result.

scholarly journals Comparison of tensile properties of thermo cured acrylic resins for the preparation of denture bases

2017 ◽  
Vol 19 (1) ◽  
Author(s):  
Juán José Castillo ◽  
Santiago Herrera ◽  
Pablo Andrés Rey ◽  
Carlos Mejía Pavony ◽  
Adriana Jaramillo
Keyword(s):  
Tensile Strength ◽  
Modulus Of Elasticity ◽  
Laboratory Tests ◽  
Acrylic Resin ◽  
High Impact ◽  
Technical Standard ◽  
Fracture Elongation ◽  
Acrylic Resins ◽  
Significant Difference

SUMMARYObjective: The purpose of this in vitro studywas to compare the tensile strength betweentwo materials for the manufacture ofacrylic denture bases (Veracril® from NewStetic and SR Triplex Hot® from IvoclarVivadent), and to know the mechanicalproperties of materials to study that haveclinical implications.Methods: Laboratory tests were conductedunder the technical standard of ASTMInternational # D 638-03 to evaluate thetwo acrylic resin materials for denturebases, processed by pressed moulding. Theobservations were made using the universaltesting machine Tinius Olsen® brandH50KS to analyze the tensile propertiessuch as modulus of elasticity, elongation,yield strength, maximum strength, energy,effort and tensile stress between the twomaterials evaluated.Results: For the effort, maximum strengthand modulus of elasticity, high-impactacrylic resin SR Triplex Hot® showedhigher values. With regard to the characteristicsof maximum displacementbefore the fracture, elongation and energy,conventional acrylic resin showed highervalues. The only characteristic that showeda significant difference between the twogroups of thermo-cured acrylic resin wasthe modulus of elasticity where the highimpactacrylic resin obtained a much highervalue than conventional acrylic resin.Conclusions: The acrylic resin SR TriplexHot® presents higher values in some tensileproperties, while the Veracril® showsbetter in others. The only characteristic thatshowed a significant difference betweenthe two acrylic resins was the modulus ofelasticity.Keywords: Acrylic resin denture bases,tensile strength, high impact acrylic resin.

scholarly journals Evaluation Flexural Strength of PMMA Resins with the Addition of Nanoparticles

2021 ◽  
Author(s):  
Canan Akay ◽  
Duygu Karakis
Keyword(s):  
Flexural Strength ◽  
Acrylic Resin ◽  
Bending Test ◽  
Zro2 Nanoparticles ◽  
Control Group ◽  
Test Machine ◽  
Three Point Bending ◽  
Acrylic Resins ◽  
Heat Cure ◽  
Topographic Characteristics

Abstract The flexural strength of heat cure acrylic resin was investigated by adding different concentrations of TiO2 and ZrO2 nanoparticles to increase its mechanical properties. ZrO2 and TiO2 nanoparticles were added at 1, 3, and 5% concentrations to the powder portion of heat polymerized acrylic resins. A total of 49 samples were prepared in 65 × 10 × 3 mm size. The structural characterisations of all experimental groups were determined by Fourier transform infrared spectroscopy. Flexural strength of the resin specimens was evaluated with a three-point bending test in a universal test machine and then examined under by scanning electron microscope to assess its topographic characteristics. The highest flexural strength value was obtained for 3% TiO2, while the lowest values were obtained for 1% and 5% TiO2. 1% ZrO2 and 3% TiO2 groups showed statistically higher flexural strength values than the control group. Addition of 3% and 5% ZrO2 and 1% and 5% TiO2 showed statistically lower flexural strength than the control group.

scholarly journals Avaliação de soluções antifúngicas de guanidina para resina base de dentadura: um estudo in vitro

2020 ◽  
Vol 61 (2) ◽  
pp. 39-49
Author(s):  
Maria Eduarda Rodrigues Gama ◽  
Vicente Castelo Branco Leitune ◽  
Isadora Martini Garcia ◽  
Stéfani Becker Rodrigues ◽  
Fabrício Mezzomo Collares
Keyword(s):  
Surface Roughness ◽  
Antifungal Activity ◽  
Flexural Strength ◽  
Guanidine Hydrochloride ◽  
Acrylic Resin ◽  
Control Group ◽  
Distilled Water ◽  
Acrylic Resins ◽  
Polyhexamethylene Guanidine

Background: The purposes of this study were: (1) to formulate polyhexamethylene guanidine hydrochloride (PHMGH) solutions at different concentrations; (2) to evaluate their antifungal activity against a mature biofilm of Candida albicans on acrylic resins; (3) to evaluate possible effects on acrylic resins flexural strength and surface roughness. Methods: PHMGH solutions were formulated with distilled water and 0.125, 0.250, or 0.5 wt.% of PHMGH. One group without PHMGH was used as control. For antifungal activity analysis, acrylic resin specimens were contaminated with C. albicans. Specimens were immersed in PHMGH solutions or distilled water for 5 or 10 min. Ultimate flexural strength and surface roughness of acrylic resins were evaluated. Results: All PHMGH solutions at 5 or 10 min showed antifungal activity compared to the control group (p

scholarly journals Comparison of Fracture Resistance in Thermal and Self-Curing Acrylic Resins—An In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Research Work ◽  
Testing Machine ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Thermosetting Resins ◽  
Acrylic Resins ◽  
The Difference

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.

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