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.

scholarly journals Evaluation of mechanical properties of fluoride-releasing dental materials after multiple fluoride recharge/discharge application

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Burak Gümüştaş ◽  
Elif Yaman Dosdoğru ◽  
Sinan Güneysu
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Dental Materials ◽  
Experimental Period ◽  
Strength Properties ◽  
Fluoride Release ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Mechanical And Physical Properties ◽  
Restorative Materials

This study aimed to determine the mechanical properties of fluoride-releasing dental materials after an accelerated fluoride recharge/discharge procedure. Two fluoride-releasing glass ionomer types of cement (Ketac Molar Easymix and IonoStar Molar), a resin-modified glass ionomer (Photac Fil Quick Aplicap), and two compomers (Compoglass F and Glasiosite) were used in this study. A total of 30 rectangular specimens and 30 disk specimens of each material were prepared and placed in distilled/deionized water (n = 5). The amount of fluoride released was analyzed from the materials for 7-day discharge, 1st recharge, 7-day discharge, 2nd recharge, and 7-day discharge, and 3rd recharge. The de/pre- and post-recharge fluoride release were measured using an ion chromatography for 24 days. The flexural strength and microhardness of each group were evaluated. The microhardness of all restorative materials showed no significant change (p > 0.05) over the experimental period. The flexural strength properties of the restorative materials did not change within the time of the study. The study showed that the fluoride release/uptake causes no effect on the mechanical and physical properties of dental materials.  

scholarly journals Effects of Bacterial Cellulose Nanocrystals on the Mechanical Properties of Resin-Modified Glass Ionomer Cements

2020 ◽  
Author(s):  
Marzieh Moradian ◽  
Mohsen Nosrat Abadi ◽  
Dana Jafarpour ◽  
Maryam Saadat
Keyword(s):  
Mechanical Properties ◽  
Bacterial Cellulose ◽  
Cellulose Nanocrystals ◽  
Modulus Of Elasticity ◽  
Testing Machine ◽  
Control Group ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Level Of Significance

Abstract Objectives The purpose of this study was to evaluate the effect of bacterial cellulose nanocrystals (BCNCs) on the mechanical properties of resin-modified glass ionomer cements (RMGICs) including compressive strength (CS), diametral tensile strength (DTS), and modulus of elasticity (E). Materials and Methods BCNCs were incorporated into RMGIC at various concentrations (0.3, 0.5, and 1 wt%). Unmodified RMGIC was used as the control group. The specimens were stored in distilled water at 37°C for 24 hours. CS and DTS, as well as modulus of elasticity, were evaluated using a universal testing machine. The nanostructure of BCNCs was observed via field emission scanning electron microscopy. Statistical Analysis One-way analysis of variance and post-hoc Tukey tests were used for data analysis. Level of significance was at p < 0.05. Results The addition of BCNCs to RMGIC led to an increase in all of the tested mechanical properties compared with the control group, with a significant increase observed for 1 wt% BCNC. CS and DTS improved up to 23%, and modulus of elasticity increased by 44%. Conclusions The addition of BCNCs to the RMGIC improved the mechanical properties, including CS, elastic modulus, and DTS. Thus, the newly developed RMGICs with BCNCs might represent an ideal and promising novel dental material in restorative dentistry.

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 The effect of different organic solvents on the degradation of restorative materials

2013 ◽  
Vol 07 (03) ◽  
pp. 347-351 ◽  
Author(s):  
Josué Martos ◽  
Luiz Fernando Machado Silveira ◽  
Carina Folgearini Silveira ◽  
Luis Antonio Suita de Castro ◽  
Carmen María Ferrer-Luque
Keyword(s):  
Organic Solvents ◽  
Control Group ◽  
Distilled Water ◽  
Glass Ionomer ◽  
Orange Oil ◽  
Significance Level ◽  
Eucalyptus Oil ◽  
Resin Modified Glass Ionomer ◽  
Restorative Materials ◽  
The Difference

ABSTRACT Objective: To evaluate the solubility of three restorative materials exposed to the different endodontic solvents. Materials and Methods: The organic solvents eucalyptus oil, xylol, chloroform, and orange oil, with distilled water as the control group was utilized. The restorative materials light-cured resin (Filtek Z250/3M ESPE), light-cured-resin-reinforced glass ionomer (Riva Light Cure LC/Southern Dental Industries SDI]) and resin-modified glass ionomer (Vitremer/3M ESPE) were analyzed. A total of 50 disks containing specimens (2 mm Χ 8 mm Ø) were prepared for each of the three classes of restorative materials, which were divided into 10 groups (n = 5) for immersion in eucalyptus oil, xylol, chloroform, orange oil or distilled water for periods of either 2 min or 10 min. The means of restorative material disintegration in solvents were obtained by the difference between the original preimmersion weight and the postimmersion weight in a digital analytical scale. Data were statistically analyzed by two-way analysis of variance while the difference between the materials was analyzed by Student-Newman-Keuls test. The significance level set at 0.05. Results: Vitremer showed the highest solubility, followed by Riva LC, and these were statistically different from eucalyptus oil, xylol, chloroform, and distilled water (P < 0.05). Regarding the immersion time in solvents, there were no significant differences between the two tested periods (P > 0.05). Conclusions: The solvents minimally degraded the composite resin, although they did influence the degradation of both resin-modified glass ionomer resin and resin reinforced with glass ionomer.

scholarly journals Effect of Zirconia and Alumina Fillers on the Microstructure and Mechanical Strength of Dental Glass Ionomer Cements

2016 ◽  
Vol 10 (1) ◽  
pp. 58-68 ◽  
Author(s):  
Júlio C. M. Souza ◽  
Joel B. Silva ◽  
Andrea Aladim ◽  
Oscar Carvalho ◽  
Rubens M. Nascimento ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Cycling ◽  
Resin Composite ◽  
Artificial Saliva ◽  
Glass Ionomer Cement ◽  
Control Group ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Inorganic Particles ◽  
Resin Modified Glass Ionomer

Background: Glass-ionomer cements perform a protective effect on the dentin-pulp complex considering the F ions release and chemical bonding to the dental structures. On the other hand, those materials have poor physic-mechanical properties in comparison with the restorative resin composite. The main aim of this work was to evaluate the influence of zirconia and/or alumina fillers on the microstructure and strength of a resin modified glass-ionomer cement after thermal cycling. Methods: An in vitro experimental study was carried out on 9 groups (n = 10) of cylindrical samples (6 x 4 mm) made from resin modified glass-ionomer (Vitremer, 3M, USA) with different contents of alumina and/or zirconia fillers. A nano-hybrid resin composite was tested as a control group. Samples were mechanically characterized by axial compressive tests and electron scanning microscopy (SEM) coupled to energy dispersive X-ray spectrophotometry (EDS), before and after thermal cycling. Thermal cycling procedures were performed at 3000, 6000 and 10000 cycles in Fusayama´s artificial saliva at 5 and 60 oC. Results: An improvement of compressive strength was noticed on glass-ionomer reinforced with alumina fillers in comparison with the commercial glass ionomer. SEM images revealed the morphology and distribution of alumina or zirconia in the microstructure of glass-ionomers. Also, defects such as cracks and pores were detected on the glass-ionomer cements. The materials tested were not affected by thermal cycling in artificial saliva. Conclusion: Addition of inorganic particles at nano-scale such as alumina can increase the mechanical properties of glass-ionomer cements. However, the presence of cracks and pores present in glass-ionomer can negatively affect the mechanical properties of the material because they are areas of stress concentration.

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 Extract of Propolis on Resin-Modified Glass Ionomer Cement: Effect on Mechanical and Antimicrobial Properties and Dentin Bonding Strength

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Narges Panahandeh ◽  
Fatemeh Adinehlou ◽  
Seyedeh Mahsa Sheikh-Al-Eslamian ◽  
Hassan Torabzadeh
Keyword(s):  
Antibacterial Activity ◽  
Flexural Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Glass Ionomer Cement ◽  
Antimicrobial Properties ◽  
Control Group ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Ionomer Cement

This study assessed the effect of addition of aqueous extract of propolis in different concentrations on the mechanical and antimicrobial properties of resin-modified glass ionomer cement (RMGIC). In this in vitro study, powder of Fuji II LC RMGIC was mixed with 25% and 50% aqueous extracts of propolis. Samples (n = 15 for shear bond strength, n = 5 for flexural strength, and n = 20 for the antibacterial activity test) were fabricated using this mixture. The buccal and lingual surfaces of 23 premolars were ground to expose dentin. Tygon tubes were filled with cement, bonded to dentin, and subjected to bond or the flexural strength test in a universal testing machine. Antibacterial activity was assessed using the disc diffusion and well-plate techniques against S. mutans. Data were analyzed using one-way ANOVA and Tukey’s test. The three groups showed significant differences ( p  < 0.001). The 50% propolis group had the lowest flexural and shear bond strength. The control group had the highest flexural and shear bond strength. No growth inhibition zone was noted around any of the discs. It can be concluded that addition of propolis to RMGIC did not confer any antibacterial activity against S. mutans and decreased the flexural and shear bond strength of RMGIC.

Flexural Properties of Bioactive Restoratives in Cariogenic Environments

2021 ◽  
Author(s):  
AU Yap ◽  
HS Choo ◽  
HY Choo ◽  
NA Yahya
Keyword(s):  
Flexural Strength ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Flexural Properties ◽  
Glass Ionomer ◽  
Bioactive Materials ◽  
Flexural Testing ◽  
Resin Modified Glass Ionomer ◽  
Ph Cycling ◽  
Acidic Conditions

Clinical Relevance The strength of some bioactive materials can be compromised by cariogenic challenges. This may impact the clinical longevity of restorations, especially in stress-bearing areas. SUMMARY This study determined the mechanical performance of bioactive restoratives in cariogenic environments and compared the flexural properties of various bioactive materials. The materials evaluated included a conventional resin-based composite (Filtek Z350 [FZ]) and 3 bioactive restoratives, namely an alkasite (Cention N [CN]), a giomer (Beautifil-bulk Restorative [BB]), and an enhanced resin-modified glass ionomer (Activa Bioactive Restorative [AV]). Beam-shaped specimens (12 x 2 x 2 mm) were produced, randomly allocated to 4 groups (n=10), and conditioned in deionized solution, remineralizing solution, demineralizing solution (DE), or pH cycled for 14 days at 37°C. After conditioning/pH cycling, the specimens were subjected to 3-point flexural testing. Flexural data were subjected to statistical analysis using analysis of variance or Tukey’s test (α=0.05). Mean flexural modulus and strength ranged from 3.54 ± 0.33 to 7.44 ± 0.28 GPa, and 87.07 ± 8.99 to 123.54 ± 12.37 MPa, respectively. While the flexural modulus of the bioactive restoratives was not affected by cariogenic/acidic conditions, flexural strength usually decreased, with the exception of CN. The strength of BB was significantly reduced by DE and pH cycling, while that of AV was lowered by DE. For all conditioning mediums, AV had a significantly lower modulus than the other materials. Apart from conditioning in DE, where differences in flexural strength was insignificant, FZ and AV were generally significantly stronger than BB and CN. The effect of cariogenic environments on flexural strength was found to be material dependent, and aside from the alkasite material (CN), cariogenic conditions were observed to significantly decrease the strength of bioactive restoratives.

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.

The Potential of a Bioactive, Pre-reacted, Glass-Ionomer Filler Resin Composite to Inhibit the Demineralization of Enamel in Vitro

2021 ◽  
Vol 46 (1) ◽  
pp. E11-E20
Author(s):  
IF Leão ◽  
N Araújo ◽  
CK Scotti ◽  
RFL Mondelli ◽  
MM de Amoêdo Campos Velo ◽  
...  
Keyword(s):  
Resin Composite ◽  
Surface Hardness ◽  
Composition Analysis ◽  
Glass Ionomer ◽  
Material Interface ◽  
Enamel Demineralization ◽  
Restorative Materials ◽  
Ph Cycling ◽  
Group B

Clinical Relevance A prereacted, glass-ionomer filler fluoride-containing resin composite had lower remineralization potential than glass-ionomer cements but was able to inhibit enamel demineralization; thus, it may be an option for restoring dental surfaces for patients at high risk of caries. SUMMARY Evidence is lacking on the use of surface prereacted glass-ionomer filler resin composites to inhibit demineralization and that simulate real clinical conditions. The present laboratory study evaluated the potential of such composites to prevent demineralization and quantified fluoride (F) and other ions released from restorative materials after a dynamic pH-cycling regimen applied to the tooth material interface in vitro. The pH-cycling regimen was assessed by measuring surface hardness (SH) along with energy dispersive X-ray spectroscopy (EDX). Methods and Materials: Ninety blocks of bovine enamel were subjected to composition analysis with EDX, and were further categorized based on SH. The blocks were randomly divided into 6 treatment groups (n=15 each): F IX (Fuji IX Extra; GC Corporation); IZ (Ion Z, FGM); F II (Fuji II LC, GC Corporation); B II (Beautifil II, Shofu); F250 (Filtek Z250 XT, 3M ESPE); and NT (control, no treatment). The blocks were subjected to a dynamic pH-cycling regimen at 37°C for 7 days concurrently with daily alternations of immersion in demineralizing/remineralizing solutions. EDX was conducted and a final SH was determined at standard distances from the restorative materials (150, 300, and 400 μm). Results: The EDX findings revealed a significant increase in F concentration and a decrease in Ca2+ in the enamel blocks of group B II after the pH-cycling regimen (p&lt;0.05). SH values for groups F IX, IZ, and F II were greater than those for groups B II, F250, and NT at all distances from the materials. Conclusions: The results suggest that each of 3 restorative materials, F IX, IZ, and F II, partially inhibited enamel demineralization under a dynamic pH-cycling regimen.

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