scholarly journals Flexural Strength and Hardness of Filler-Reinforced PMMA Targeted for Denture Base Application

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2659
Author(s):  
Abdulaziz Alhotan ◽  
Julian Yates ◽  
Saleh Zidan ◽  
Julfikar Haider ◽  
Nikolaos Silikas
Keyword(s):  
Flexural Strength ◽  
Glass Fibre ◽  
Surface Hardness ◽  
Bending Test ◽  
Zro2 Nanoparticles ◽  
Filler Concentration ◽  
Control Group ◽  
Denture Base ◽  
Three Point Bending ◽  
Pmma Resin

The aim of this work was to evaluate the flexural strength and surface hardness of heat-cured Polymethyl methacrylate (PMMA) modified by the addition of ZrO2 nanoparticles, TiO2 nanoparticles, and E-glass fibre at different wt.% concentrations. Specimens were fabricated and separated into four groups (n = 10) to measure both flexural strength and surface hardness. Group C was the control group. The specimens in the remaining three groups differed according to the ratio of filler to weight of PMMA resin (1.5%, 3%, 5%, and 7%). A three-point bending test was performed to determine the flexural strength, while the surface hardness was measured using the Vickers hardness. Scanning Electron Microscope (SEM) was employed to observe the fractured surface of the specimens. The flexural strength was significantly improved in the groups filled with 3 wt.% ZrO2 and 5 and 7 wt.% E-glass fibre in comparison to Group C. All the groups displayed a significantly higher surface hardness than Group C, with the exception of the 1.5% TiO2 and 1.5% ZrO2 groups. The optimal filler concentrations to enhance the flexural strength of PMMA resin were between 3–5% ZrO2, 1.5% TiO2, and 3–7% E-glass fibre. Furthermore, for all composites, a filler concentration of 3 wt.% and above would significantly improve hardness.

scholarly journals Influence of Different Reline Materials and Processing Methods on Flexural Strength of Denture Base Material

2021 ◽  
Vol 25 (2) ◽  
pp. 108-113
Author(s):  
Ozlem Gurbuz Oflezer ◽  
Hakan Bahadır ◽  
Senem Ünver ◽  
Ceyhan Oflezer
Keyword(s):  
Flexural Strength ◽  
Base Material ◽  
Acrylic Resin ◽  
Bending Test ◽  
Control Group ◽  
Processing Methods ◽  
Denture Base ◽  
Three Point Bending ◽  
Heat Cure ◽  
And Control

Summary Background/Aim: Relining is defined as the procedure used to resurface the tissue side of a denture with new base material, thus producing an accurate adaptation is provided at the denture foundation area. During mastication, relined dentures have to withstand masticatory forces to prevent fracture. The aim of this study was to evaluate the flexural strength of acrylic resin denture base relined with different methods and materials. Material and Methods: Fourteen experimental groups and one control group were determined to consider different reline materials and processing methods. Acrylic resin specimens were prepared with the dimensions of 65× 10× 1.5 mm and reline materials (1.5 mm thickness) were placed on acrylic resins. Reline material was not used in control group specimens. Flexural strength values of relined and control specimens were measured with three-point bending test at a speed of 5 mm/min. Data were analyzed with using one way Anova and Student t tests. Results: The highest flexural strength values were shown in control group (86.51±1.08 MPa). There were significant differences among relined specimens (p< 0.05). For the relined specimens, the highest flexural strength values were found in the relined specimens with denture base material (77.90±1.93 MPa), and the lowest values were found in relined with autopolymerize acrylic material (59.81±1.50 MPa). Conclusions: Relining of the heat cure denture base material significantly decreases the flexural strength for all processing methods and materials.

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 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 Effects of SiO2 Incorporation on the Flexural Properties of a Denture Base Resin: An In Vitro Study

2021 ◽  
Author(s):  
Sara T. Alzayyat ◽  
Ghadah A. Almutiri ◽  
Jawhara K. Aljandan ◽  
Raneem M. Algarzai ◽  
Soban Q. Khan ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Flexural Strength ◽  
Testing Machine ◽  
Base Material ◽  
Bending Test ◽  
Control Group ◽  
Denture Base ◽  
Nano Sio2 ◽  
Base Resin ◽  
Denture Base Resin

Abstract Objective The aim of this study was to evaluate the effects of the addition of low-silicon dioxide nanoparticles (nano-SiO2) on the flexural strength and elastic modulus of polymethyl methacrylate (PMMA) denture base material. Materials and Methods A total of 50 rectangular acrylic specimens (65 × 10 × 2.5 mm3) were fabricated from heat-polymerized acrylic resin. In accordance with the amount of nano-SiO2, specimens were divided into the following five groups (n = 10 per group): a control group with no added SiO2, and four test groups modified with 0.05, 0.25, 0.5, and 1.0 wt% nano-SiO2 of acrylic powder. Flexural strength and elastic modulus were measured by using a 3-point bending test with a universal testing machine. A scanning electron microscope was used for fracture surface analyses. Data analyses were conducted through analysis of variance and Tukey’s post hoc test (α = 0.05). Results Compared with the control group, flexural strength and modulus of elasticity tended to significantly increase (p ˂ 0.001) with the incorporation of nano-SiO2. In between the reinforced groups, the flexural strength significantly decreased (p ˂ 0.001) as the concentrations increased from 0.25 to 1.0%, with the 1.0% group showing the lowest value. Furthermore, the elastic modulus significantly increased (p ˂ 0.001) at 0.05% followed by 1.0%, 0.25%, 0.5%, and least in control group. Conclusion A low nano-SiO2 addition increased the flexural strength and elastic modulus of a PMMA denture base resin.

scholarly journals Comparative analysis of ceramic flexural strength in co-cr and ni-cr alloys joined by TIG welding and conventional brazing

2017 ◽  
Vol 16 ◽  
pp. 1-9
Author(s):  
Adaias Oliveira Matos ◽  
Cristiane de Castro Castelo Branco ◽  
Eliza Burlamaqui Klautau ◽  
Bruno Pereira Alves
Keyword(s):  
Flexural Strength ◽  
Tig Welding ◽  
Bending Test ◽  
Control Group ◽  
Cobalt Chromium ◽  
Bond Failure ◽  
Three Point Bending ◽  
Nickel Chromium ◽  
Ceramic Bond ◽  
Bond Strengths

The purpose of the present study was to evaluate the flexural strength of specimens made of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys and joined by tungsten inert gas (TIG) welding and conventional brazing. Ni–Cr and Co–Cr base metal specimens (n = 40, each) were cast and welded by TIG or brazing. The specimens were divided into six groups (2 base metals, four welded specimens). Ceramic systems were applied to the central part of all the specimens. A three-point bending test with a velocity of 0.5 mm/m was performed on the specimens up to the point of the first ceramic bond failure by measuring the flexural strength. Data were analyzed using two-way ANOVA and Bonferroni’s tests. Conventional welding showed the lowest flexural strength results for both alloys, while the TIG weld and the control group presented with varying bond strengths for the alloys studied. We concluded that TIG welding was superior to the conventional welding method for both Ni–Cr and Co–Cr alloys with regard to the flexural strength of the ceramic.

scholarly journals Reinforcement of PMMA Denture Base Material with a Mixture of ZrO2Nanoparticles and Glass Fibers

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammed M. Gad ◽  
Ahmad M. Al-Thobity ◽  
Ahmed Rahoma ◽  
Reem Abualsaud ◽  
Fahad A. Al-Harbi ◽  
...  
Keyword(s):  
Impact Strength ◽  
Flexural Strength ◽  
Glass Fibers ◽  
Base Material ◽  
Test Group ◽  
Charpy Impact ◽  
Bending Test ◽  
Control Group ◽  
Denture Base ◽  
The Impact

This study is aimed at evaluating the hybrid reinforcement effects of zirconium oxide nanoparticles (nano-ZrO2) and glass fibers (GFs) at different ratios on the flexural and impact strengths of a polymethylmethacrylate (PMMA) denture base. A total of 160 specimens were fabricated from heat-polymerized acrylic resins using the water bath technique. For the control group, the specimens did not receive any additions; for the test group, different concentrations of nano-ZrO2/GFs at 5% of the PMMA polymer were added. The concentrations of nano-ZrO2/GFs were as follows: 5%–0%, 4%–1%, 3%–2%, 2.5%–2.5%, 2%–3%, 1%–4%, and 0%–5%. The flexural strength was measured using the three-point bending test. The impact strength was measured using the Charpy impact test. Results were tabulated and analyzed using one-way analysis of variance (ANOVA) and the Tukey–Kramer multiple comparison test (p≤0.05). The flexural and impact strengths of PMMA-nano-ZrO2 + GF composites were significantly improved when compared with those of pure PMMA (p<0.05). The maximum flexural strength (94.05 ± 6.95 MPa) and impact strength (3.89 ± 0.46 kJ/m2) were obtained with PMMA (2.5%)/nano-ZrO2 + 2.5% GF mixtures and could be used for removable prosthesis fabrication.

scholarly journals Effect of SiO2 Nanoparticles Addition on the Flexural Strength of Repaired Acrylic Denture Base

2020 ◽  
Vol 14 (01) ◽  
pp. 019-023 ◽  
Author(s):  
Mohammed Moustafa Ahmed Gad ◽  
Reem Abualsaud ◽  
Ahmad M. Al-Thobity ◽  
Danah F. Almaskin ◽  
Zahra A. AlZaher ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Acrylic Resin ◽  
Sio2 Nanoparticles ◽  
Analysis Data ◽  
Bending Test ◽  
Homogeneous Distribution ◽  
Filler Concentration ◽  
Sem Images ◽  
Denture Base ◽  
Nano Sio2

Abstract Objective The objective of this study was to evaluate the effect of nano-SiO2 addition on the flexural strength (FS) of repaired acrylic denture base. Materials and Methods Heat-polymerized acrylic resin specimens were fabricated in dimensions of (65 × 10 × 2.5 ± 0.1 mm3 ) and then sectioned and prepared, creating repair gap with butt (90 degrees) and bevel (45 degrees) repair surface designs forming two main groups according to joint design. Further subdivision was done into four groups (n = 10) according to nano-SiO2 concentration: one unmodified group and three modified groups (0.25, 0.5, and 0.75 wt %) in the autopolymerized repair resin. Each pair of a specimen was assembled in a mold and repaired according to manufacturer’s recommendations. Statistical Analysis Three-point bending test was done to measure FS, followed by scanning electron microscope (SEM) examination for fracture surface analysis. Data were analyzed using ANOVA and Tukey’s post hoc test (α = 0.05). Results The addition of nano-SiO2 significantly improved FS of repaired acrylic resin in comparison to the unmodified group (p ˂ 0.05). For butt joint, significant differences between nano-SiO2 reinforced groups were noticed (p ˂ 0.05), while reinforced beveled groups did not differ significantly (p ˃ 0.05). Bevel design remarkably increased FS compared with butt design per respective filler concentration. From the SEM images, improved FS was presented with a homogeneous distribution of nano-SiO2 within polymethyl methacrylate. Conclusion Nano-SiO2 addition to repair resin and 45 degree-beveled repair surface increased FS of repaired acrylic resin.

In Vitro Evaluation of Candida albicans Biofilm Formation on Denture Base PMMA Resin Incorporated with Silver Nanoparticles and its Effect on Flexural Strength

2014 ◽  
Vol 905 ◽  
pp. 51-55 ◽  
Author(s):  
Sahana Bajracharya ◽  
Sroisiri Thaweboon ◽  
Boonyanit Thaweboon ◽  
Amornrat Wonglamsam ◽  
Theerathavaj Srithavaj
Keyword(s):  
Silver Nanoparticles ◽  
Flexural Strength ◽  
Biofilm Formation ◽  
Base Material ◽  
Bending Test ◽  
Yeast Nitrogen Base ◽  
Nitrogen Base ◽  
Denture Base ◽  
Pmma Resin

The aim of this study is to investigate the candidal biofilm formation on the silver nanoparticles (AgNPs) incorporated denture base heat-polymerized (poly methyl methacrylate), PMMA, resinand its flexural strength.Materials and methods:A total of 36PMMA resin specimens (15×15×2 mm3) were fabricated and divided into 4 groups based on their AgNPs contents (0%,0.5%, 1% and 1.5% w/w of polymer). The biofilm of clinical and reference strainsof C.albicanswere grown on PMMA resin specimens in the presence of yeast nitrogen base broth supplemented with 100 mM glucose at 37oC for 48 h and evaluated by tetrazolium reduction assay. The flexural strength of PMMA resin specimens (65×10×3.3 mm3) were tested by using three-point bending test. Data were analyzed by Kruskal-Wallis and Mann-Whitney U test at p<0.05. result:all="" 3="" groups="" with="" agnps="" showed="" significant="" reduction="" in="" biofilm="" formation="" of="" both="" strains="" i="">C.albicans compared to control (0% AgNPs) (p<0.05). Decreased flexural strength was observed with AgNPs groups compared with the control but within acceptable limit of ISO 20795-1. Conclusion:The reduction of the C. albicans biofilm was observed on the heat-polymerized PMMA resin incorporated with AgNPs. Regarding the flexural strength, the values were within ISO limit. These modified PMMA resin can be developed for the prevention or treatment of the candidal infection associated with the denture base material.

scholarly journals Behaviour of PMMA Resin Composites Incorporated with Nanoparticles or Fibre following Prolonged Water Storage

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3453
Author(s):  
Abdulaziz Alhotan ◽  
Julian Yates ◽  
Saleh Zidan ◽  
Julfikar Haider ◽  
Carlos Alberto Jurado ◽  
...  
Keyword(s):  
Water Sorption ◽  
Water Solubility ◽  
Negative Influence ◽  
Zro2 Nanoparticles ◽  
Control Group ◽  
Denture Base ◽  
Significance Level ◽  
The Difference ◽  
Post Hoc ◽  
Pmma Resin

When PMMA denture base acrylics are exposed to oral environments for prolonged periods, the denture base absorbs water, which has a negative influence on the denture material and the degree to which the denture base will be clinically effective. This study assessed the water sorption, desorption, and hygroscopic expansion processes within PMMA denture-base resins reinforced with nanoparticles or fibre in comparison to the non-reinforced PMMA. The surfaces of the fillers were modified using a silane coupling agent (y-MPS) before mixing with PMMA. Group C consisted of specimens of pure PMMA whereas groups Z, T, and E consisted of PMMA specimens reinforced with ZrO2, TiO2 nanoparticles, or E-glass fibre, respectively. The reinforced groups were subdivided into four subgroups according to the percentage filler added to the PMMA resin by weight (1.5%, 3.0%, 5.0%, or 7.0%). Five specimens in disc shape (25 ± 1 mm × 2.0 ± 0.2 mm) were tested for each group. To assess water sorption and hygroscopic expansion, specimens from each group were individually immersed in water at 37 ± 1 °C for 180 days. The samples were then desorbed for 28 days at 37 ± 1 °C, to measure solubility. Water sorption and solubility were calculated using an electronic balance in accordance with ISO Standard 20795-1, and hygroscopic expansion was measured using a laser micrometre. Statistical analysis was undertaken at a p ≤ 0.05 significance level using a one-way ANOVA followed by Tukey post-hoc tests. The results demonstrated that the values of sorption (Wsp), mass sorption (Ms%), and % expansion within the tested groups reached equilibrium within 180 days. A noticeable difference was observed in groups Z and E for (Wsp)/(Ms%) compared to the Group C, but this was not significant. However, the difference between Group C and Group T for these measurements was significant. Non-significant differences also existed between each respective reinforced group and the control group in terms of hygroscopic expansion % values. During the 28-day desorption period, there were no differences in the values of solubility (Wsl)/mass desorption (Md%) between Group C and each of the reinforced tested groups. The findings indicate that the inclusion of ZrO2 nanoparticles or E-glass fibres does not increase the water solubility/sorption of the PMMA. However, modifying the PMMA with TiO2 did significantly increase the water sorption level.

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.

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