scholarly journals Novel Poly(Methyl Methacrylate) Containing Nanodiamond to Improve the Mechanical Properties and Fungal Resistance

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3438 ◽  
Author(s):  
Utkarsh Mangal ◽  
Ji-Yeong Kim ◽  
Ji-Young Seo ◽  
Jae-Sung Kwon ◽  
Sung-Hwan Choi
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Methyl Methacrylate ◽  
Vickers Hardness ◽  
Surface Hardness ◽  
Fungal Resistance ◽  
Control Group ◽  
Poly Methyl Methacrylate ◽  
Fungal Adhesion

Herein we evaluate the effect of nanodiamond (ND) incorporation on the mechanical properties of poly(methyl methacrylate) (PMMA) nanocomposite. Three quantities of ND (0.1, 0.3, and 0.5 wt.%) were tested against the control and zirconium oxide nanoparticles (ZrO). Flexural strength and elastic modulus were measured using a three-point bending test, surface hardness was evaluated using the Vickers hardness test, and surface roughness was evaluated using atomic force microscopy (AFM), while fungal adhesion and viability were studied using Candida albicans. Samples were also analyzed for biofilm thickness and biomass in a saliva-derived biofilm model. All groups of ND-PMMA nanocomposites had significantly greater mean flexural strengths and statistically improved elastic modulus, compared to the control and ZrO groups (P < 0.001). The Vickers hardness values significantly increased compared to the control group (P < 0.001) with 0.3% and 0.5% ND. ND addition also gave significant reduction in fungal adhesion and viability (P < 0.001) compared to the control group. Finally, salivary biofilm formation was markedly reduced compared to the ZrO group. Hence, the incorporation of 0.1–0.5 wt.% ND with auto- polymerized PMMA resin significantly improved the flexural strength, elastic modulus, and surface hardness, and provided considerable fungal resistance.

scholarly journals Mechanical properties of an experimental resin based composite containing silver nanoparticles and bioactive glass

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Amjad Hanif ◽  
Fazal Ghani
Keyword(s):  
Mechanical Properties ◽  
Silver Nanoparticles ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Bioactive Glass ◽  
Vickers Hardness ◽  
Control Group ◽  
The Difference ◽  
Hardness Values ◽  
Made In

Objective: To compare the elastic modulus, flexural strength, and hardness of an experimental resin based composite (RBC) with and without containing silver nanoparticles (AgNPs) and bioactive glass (BAG) with a commercially available RBC. Methods: This study was conducted, during the period August 2016-May 2018, at the Department of Dental Materials, Peshawar Dental College, Peshawar (Pakistan) and Department of Chemistry, University of Montreal, Canada. Test specimens made in the commercial RBC acted as Group-1 (G1). An experimental RBC containing 70 wt % filler content was synthesized. It was first used as such to prepare test specimens to act as the experimental control group (G2). This RBC was then modified by adding various amounts of BAG (5%, 10% and 15%) and a fixed amount of 0.009% AgNPs to use the so modified RBCs for preparing the test specimens to belong to three groups (G3, G4 & G5). The AgNPs had been synthesized in situ by reduction of salt during photo-polymerization. Flexural strength (FS), elastic modulus (EM) and Vickers hardness were determined using universal testing machine and hardness tester respectively. Data were analyzed using one-way ANOVA and Tukey post-hoc test. Results: Except for G3 restorations showing significantly lower mean FS value, the FS for those in the other groups were not significantly different (p>0.05). Elastic modulus of the experimental RBC restorations was though higher than those of the others but the difference was statistically insignificant (p>0.05). Reduced Vickers hardness values were documented for the restorations in the G4 and G5 compared to those in the G3 but again the difference was insignificant (p>0.05). Flexural strength and hardness values of the test specimens in the experimental RBCs were significantly lower than those made in the commercial hybrid RBC (p<0.05). Conclusion: BAG and AgNPs addition to the experimental RBC in the mentioned concentration adversely affected the tested mechanical properties. doi: https://doi.org/10.12669/pjms.36.4.1913 How to cite this:Hanif A, Ghani F. Mechanical properties of an experimental resin based composite containing silver nanoparticles and bioactive glass. Pak J Med Sci. 2020;36(4):---------. doi: https://doi.org/10.12669/pjms.36.4.1913 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

scholarly journals Effect of Camphorquinone Concentration in Physical-Mechanical Properties of Experimental Flowable Resin Composites

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Dayany da Silva Alves Maciel ◽  
Arnaldo Bonfim Caires-Filho ◽  
Marta Fernandez-Garcia ◽  
Camillo Anauate-Netto ◽  
Roberta Caroline Bruschi Alonso
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Mechanical Strength ◽  
Surface Hardness ◽  
Degree Of Conversion ◽  
Bending Test ◽  
Resin Matrix ◽  
Shrinkage Stress ◽  
Depth Of Cure

The aim of this study was to evaluate the effect of camphorquinone concentration in physical-mechanical properties of experimental flowable composites in order to find the concentration that results in maximum conversion, balanced mechanical strength, and minimum shrinkage stress. Model composites based on BISGMA/TEGDMA with 70% wt filler loading were prepared containing different concentrations of camphorquinone (CQ) on resin matrix (0.25%, 0.50%, 1%, 1.50%, and 2% by weight). Degree of conversion was determined by FTIR. Surface hardness was assessed before and after 24 h ethanol storage and softening rate was determined. Depth of cure was determined by Knoop hardness evaluation at different depths. Color was assessed by reflectance spectrophotometer, employing the CIE-Lab system. Flexural strength and elastic modulus were determined by a three-point bending test. Shrinkage stress was determined in a Universal Testing Machine in a high compliance system. Data were submitted to ANOVA and Tukey’s test (α = 0.05). The increase in CQ concentration caused a significant increase on flexural strength and luminosity of composites. Surface hardness was not affected by the concentration of CQ. Composite containing 0.25% wt CQ showed lower elastic modulus and shrinkage stress when compared to others. Depth of cure was 3 mm for composite containing 1% CQ and 2 mm for the other tested composites. Degree of conversion was inversely correlated with softening rate and directly correlated with elastic modulus and shrinkage stress. In conclusion, CQ concentration affects polymerization characteristics and mechanical strength of composites. The concentration of CQ in flowable composite for optimized polymerization and properties was 1% wt of the resin matrix, which allows adequate balance among degree of conversion, depth of cure, mechanical properties, and color characteristics of these materials.

scholarly journals The Mechanical Properties of a Poly(methyl methacrylate) Denture Base Material Modified with Dimethyl Itaconate and Di-n-butyl Itaconate

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Pavle Spasojevic ◽  
Milorad Zrilic ◽  
Vesna Panic ◽  
Dragoslav Stamenkovic ◽  
Sanja Seslija ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Methyl Methacrylate ◽  
Surface Hardness ◽  
Base Material ◽  
Dynamic Mechanical Properties ◽  
Denture Base ◽  
Mean Values ◽  
Poly Methyl Methacrylate ◽  
Base Materials ◽  
Wide Range

This study investigates a wide range of clinically relevant mechanical properties of poly(methyl methacrylate) (PMMA) denture base materials modified with di-methyl itaconate (DMI) and di-n-butyl itaconate (DBI) in order to compare them to a commercial PMMA denture base material. The commercial denture base formulation was modified with DMI and DBI by replacing up to 10 wt% of methyl methacrylate (MMA) monomer. The specimens were prepared by standard bath curing process. The influence of the itaconate content on hardness, impact strength, tensile, and thermal and dynamic mechanical properties was investigated. It is found that the addition of di-n-alkyl itaconates gives homogenous blends that show decreased glass transition temperature, as well as decrease in storage modulus, ultimate tensile strength, and impact fracture resistance with increase in the itaconate content. The mean values of surface hardness show no significant change with the addition of itaconates. The magnitude of the measured values indicates that the poly(methyl methacrylate) (PMMA) denture base material modified with itaconates could be developed into a less toxic, more environmentally and patient friendly product than commercial pure PMMA denture base material.

scholarly journals Development of Dental Poly(methyl methacrylate)-Based Resin for Stereolithography Additive Manufacturing

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4435
Author(s):  
Kentaro Hata ◽  
Hiroshi Ikeda ◽  
Yuki Nagamatsu ◽  
Chihiro Masaki ◽  
Ryuji Hosokawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Flexural Strength ◽  
Bond Strength ◽  
Methyl Methacrylate ◽  
Vickers Hardness ◽  
Water Sorption ◽  
Shear Bond Strength ◽  
Dental Applications

Poly(methyl methacrylate) (PMMA) is widely used in dental applications. However, PMMA specialized for stereolithography (SLA) additive manufacturing (3D-printing) has not been developed yet. This study aims to develop a novel PMMA-based resin for SLA 3D-printing by mixing methyl methacrylate (MMA), ethylene glycol dimethacrylate (EGDMA), and PMMA powder in various mixing ratios. The printability and the viscosity of the PMMA-based resins were examined to determine their suitability for 3D-printing. The mechanical properties (flexural strength and Vickers hardness), shear bond strength, degree of conversion, physicochemical properties (water sorption and solubility), and cytotoxicity for L929 cells of the resulting resins were compared with those of three commercial resins: one self-cured resin and two 3D-print resins. EGDMA and PMMA were found to be essential components for SLA 3D-printing. The viscosity increased with PMMA content, while the mechanical properties improved as EGDMA content increased. The shear bond strength tended to decrease as EGDMA increased. Based on these characteristics, the optimal composition was determined to be 30% PMMA, 56% EGDMA, 14% MMA with flexural strength (84.6 ± 7.1 MPa), Vickers hardness (21.6 ± 1.9), and shear bond strength (10.5 ± 1.8 MPa) which were comparable to or higher than those of commercial resins. The resin’s degree of conversion (71.5 ± 0.7%), water sorption (19.7 ± 0.6 μg/mm3), solubility (below detection limit), and cell viability (80.7 ± 6.2% at day 10) were all acceptable for use in an oral environment. The printable PMMA-based resin is a potential candidate material for dental applications.

scholarly journals Investigating the Mechanical Properties of ZrO2-Impregnated PMMA Nanocomposite for Denture-Based Applications

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1344 ◽  
Author(s):  
Saleh Zidan ◽  
Nikolaos Silikas ◽  
Abdulaziz Alhotan ◽  
Julfikar Haider ◽  
Julian Yates
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Surface Hardness ◽  
Bending Test ◽  
Zro2 Nanoparticles ◽  
Control Group ◽  
The Mean

Acrylic resin PMMA (poly-methyl methacrylate) is used in the manufacture of denture bases but its mechanical properties can be deficient in this role. This study investigated the mechanical properties (flexural strength, fracture toughness, impact strength, and hardness) and fracture behavior of a commercial, high impact (HI), heat-cured denture base acrylic resin impregnated with different concentrations of yttria-stabilized zirconia (ZrO2) nanoparticles. Six groups were prepared having different wt% concentrations of ZrO2 nanoparticles: 0% (control), 1.5%, 3%, 5%, 7%, and 10%, respectively. Flexural strength and flexural modulus were measured using a three-point bending test and surface hardness was evaluated using the Vickers hardness test. Fracture toughness and impact strength were evaluated using a single edge bending test and Charpy impact instrument. The fractured surfaces of impact test specimens were also observed using a scanning electron microscope (SEM). Statistical analyses were conducted on the data obtained from the experiments. The mean flexural strength of ZrO2/PMMA nanocomposites (84 ± 6 MPa) at 3 wt% zirconia was significantly greater than that of the control group (72 ± 9 MPa) (p < 0.05). The mean flexural modulus was also significantly improved with different concentrations of zirconia when compared to the control group, with 5 wt% zirconia demonstrating the largest (23%) improvement. The mean fracture toughness increased in the group containing 5 wt% zirconia compared to the control group, but it was not significant. However, the median impact strength for all groups containing zirconia generally decreased when compared to the control group. Vickers hardness (HV) values significantly increased with an increase in ZrO2 content, with the highest values obtained at 10 wt%, at 0 day (22.9 HV0.05) in dry conditions when compared to the values obtained after immersing the specimens for seven days (18.4 HV0.05) and 45 days (16.3 HV0.05) in distilled water. Incorporation of ZrO2 nanoparticles into high impact PMMA resin significantly improved flexural strength, flexural modulus, fracture toughness and surface hardness, with an optimum concentration of 3–5 wt% zirconia. However, the impact strength of the nanocomposites decreased, apart from the 5 wt% zirconia group.

scholarly journals Assessment of the Effect of Acid and Base Cycling on Mechanical Properties of Various Esthetic Restorative Materials

2021 ◽  
pp. 31-38
Author(s):  
Horieh Moosavi ◽  
Fatemeh Rezaei ◽  
Zahra Rezaei ◽  
Zahra Soroush
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Control Group ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Restorative Materials ◽  
Acid And Base ◽  
Ph Cycling ◽  
Restorative Composites

Objective: The purpose of this study is the evaluation of the effect of pH cycling, including both acidic and alkaline environments, on the mechanical properties of tooth-colored restorative materials. Methods and Materials: 20 rectangular bar specimens of one bulk-fill restorative composite, two conventional nanohybrid restorative composites, and one restorative resin-modified glass ionomer were produced according to ISO 4049. Half of the materials were stored in an acid and base cycling defined as two-day storage in acidic (pH =4) and alkaline (pH=8) solutions. The rest of the materials were incubated in distilled water as a control group. The storage lasted for 48 days. Finally, flexural strength, elastic modulus, and microhardness of the specimens in each group determined. Data analyzed with Kruskal-Wallis, Dunn, MANOVA, Tukey HSD and T-test.  Results: The pH cycling model had a significant influence on all mechanical properties of the bulk-fill restorative composite and resin-modified glass ionomer than those stored in water (P <0.05). One of the conventional nanohybrid restorative composites showed a significant reduction in elastic modulus and microhardness while the other one showed a significant reduction only in flexural strength.  Conclusion: pH cycling negatively affects the mechanical properties of resin composites, and the materials’ composition is an important factor in the degradation of the resin-based materials examined.

Effects of gamma radiation on poly(methyl methacrylate)/single-wall nanotube composites

2002 ◽  
Vol 17 (10) ◽  
pp. 2507-2513 ◽  
Author(s):  
P. A. O'Rourke Muisener ◽  
L. Clayton ◽  
J. D'Angelo ◽  
J. P. Harmon ◽  
A. K. Sikder ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Methyl Methacrylate ◽  
Vickers Hardness ◽  
Radiation Effects ◽  
Pure Pmma ◽  
Vickers Hardness Number ◽  
Poly Methyl Methacrylate ◽  
Hardness Number ◽  
The Matrix ◽  
Nanotube Composites

Single-wall carbon nanotube (SWNT)/poly(methyl methacrylate) (PMMA) composites were fabricated and exposed to ionizing radiation for a total dose of 5.9 Mrads. Neat nanotube paper and pure PMMA were also exposed for comparison, and nonirradiated samples served as controls. A concentration of 0.26 wt% SWNT increased the glass transition temperature (Tg), the Vickers hardness number, and modulus of the matrix. Irradiation of the composite did not significantly change the Tg, the Vickers hardness number, or the modulus; however, the real and imaginary parts of the complex permittivity increased after irradiation. The dielectric properties were found to be more labile to radiation effects than mechanical properties.

scholarly journals Mechanical Properties of Experimental Composites with Different Photoinitiator

2021 ◽  
Author(s):  
Luis Felipe Marques de Resende ◽  
Anderson Catelan ◽  
Kusai Baroudi ◽  
Alan Rodrigo Muniz Palialol ◽  
Alexandre Marques de Resende ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Phosphine Oxide ◽  
Light Emitting Diode ◽  
Surface Hardness ◽  
Triethylene Glycol ◽  
Bottom Surface ◽  
Significance Level ◽  
Depth Of Cure

Abstract Objective The effect of different photoinitiators on mechanical properties of experimental composites was evaluated. Materials and Methods Resin composites were formulated by using a blend of bisphenol A-glycidyl and triethylene glycol (50/50 wt%) dimethacrylate monomers, and 65 wt% of barium aluminium silicate and silica filler particles. Photoinitiators used were 0.2% camphorquinone (CQ) and 0.8% co-initiator (DMAEMA); 0.2% phenyl-propanedione and 0.8% DMAEMA; 0.1% CQ + 0.1% phenyl propanedione and 0.8% DMAEMA; 0.42% mono(acyl)phosphine oxide (MAPO); and 0.5% bis(acyl)phosphine oxide (BAPO). Specimens (n = 10) were light cured by using a multiple-emission peak light-emitting diode for 20 seconds at 1,200 mW/cm2 of irradiance and Knoop hardness and plasticization, depth of cure, flexural strength, and elastic modulus were evaluated. Data were statiscally analyzed at significance level of α = 5%. Results Experimental composites containing MAPO and BAPO photoinitiators showed the highest values of flexural strength, elastic modulus, top surface hardness, and lower hardness reduction caused by alcohol compared with CQ. Composites containing CQ and PPD showed similar results, except for depth of cure and hardness of bottom surface. Conclusion BAPO and MAPO showed higher flexural strength, elastic modulus, hardness on top surface, and lower polymer plasticization to CQ.

scholarly journals Denture base adaptation, retention, and mechanical properties of BioHPP versus nano-alumina-modified polyamide resins

2021 ◽  
Vol 15 (4) ◽  
pp. 239-246
Author(s):  
Radwa Mohsen Kamal Emera ◽  
Reham Mohammed Abdallah
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Surface Hardness ◽  
Base Material ◽  
Alumina Nanoparticles ◽  
Control Group ◽  
Denture Base ◽  
Promising Alternative ◽  
Base Materials ◽  
Group I

Background. Continuous development of denture base materials has led to the introduction of innovative alternatives to polymethyl methacrylate. The present study aimed to evaluate the mechanical properties, adaptation, and retention of alumina nanoparticles (Al2 O3 NPs) modified polyamide resin versus BioHPP (high-performance polymer) denture base materials. Methods. Four groups of specimens, one control (group I) (unmodified polyamide) and two groups (groups II and III) (2.5 and 5 wt% Al2 O3 NP-modified polyamide, respectively) versus BioHPP specimen group (group IV), were tested for surface microhardness and flexural strength. Complete dentures fabricated from 5 wt% Al2 O3 NP-modified polyamide resin and BioHPP were used to evaluate denture base adaptation and retention. Results. The higher concentration in the alumina NP-modified polyamide group (5 wt%) demonstrated significantly higher flexural strength values and insignificantly higher hardness values than the lower concentration (2.5 wt%). There was a significant increase in the BioHPP group in both flexural strength and surface hardness compared to all polyamide groups. A statistically insignificant difference was observed between the two denture base materials regarding mean misfit values of the calculated total tissue surface area and four of the total seven evaluated areas. Satisfactory and comparable retention values were observed for both denture base materials. Conclusion. BioHPP and Al2 O3 NP-modified polyamide resin could be used as a promising alternative denture base material with good adaptation, retention, and mechanical properties.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

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