scholarly journals Effects of Polymerization Mode and Interaction with Hydroxyapatite on the Rate of pH Neutralization, Mechanical Properties, and Depth of Cure in Self-Adhesive Cements

2019 ◽  
Vol 13 (02) ◽  
pp. 178-186
Author(s):  
Fabiana S. A. S. Camargo ◽  
Alejandra H. M. González ◽  
Roberta C. B. Alonso ◽  
Vinicius Di Hipólito ◽  
Paulo H. P. D'Alpino
Keyword(s):  
Mechanical Properties ◽  
Infrared Spectroscopy ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
The Self ◽  
Chemical Bonds ◽  
Resin Cements ◽  
Adhesive Resin ◽  
Depth Of Cure ◽  
Ph Neutralization

Abstract Objective The aim of the study was to evaluate the physicochemical properties of self-adhesive resin cements associated with hydroxyapatite (HAp) according to the polymerization activation. Materials and Methods Specimens of cements (PermaCem 2.0 [DMG]; MaxCem Elite [Kerr], and RelyX U200 [3M ESPE]) were distributed into three groups: activation mode; self-cured and dual-cured modes; and association or not with HAp powder mode. The pH neutralization was evaluated as a function of time. Flexural strength and elastic modulus were also tested (0.5 mm/min.). The depth of cure was also analyzed using the scraping test (ISO 4049). Infrared spectroscopy was also used to collect the spectra of specimens to evaluate the chemical bonds. Statistical comparisons were conducted at 5% of significance. Results The aggressiveness of the self-adhesive resin cements evaluated varied among the materials with a tendency for neutralization. Self-cure groups exhibited lower pH throughout the entire evaluation when compared with that of the dual-cure ones, irrespective of the addition of HAp. MaxCem Elite when photoactivated was the only cement influenced by the addition of the HAp in terms of mechanical properties. The self-adhesive cements tested presented equivalent depth of cure based on the ISO 4049 requirements, regardless of the evaluated factors. Conclusions Based on the parameters evaluated, the results demonstrated that most of the self-adhesive cements remained unaltered or improved when mixed with HAp, regardless of the activation mode.

scholarly journals Mechanical Properties and Sliding-impact Wear Resistance of Self-adhesive Resin Cements

2016 ◽  
Vol 41 (3) ◽  
pp. E83-E92 ◽  
Author(s):  
T Furuichi ◽  
T Takamizawa ◽  
A Tsujimoto ◽  
M Miyazaki ◽  
WW Barkmeier ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Sliding Wear ◽  
Resin Cement ◽  
The Self ◽  
Volume Loss ◽  
Resin Cements ◽  
Adhesive Resin

SUMMARY The present study determined the mechanical properties and impact-sliding wear characteristics of self-adhesive resin cements. Five self-adhesive resin cements were used: G-CEM LinkAce, BeautiCem SA, Maxcem Elite, Clearfil SA Automix, and RelyX Unicem 2. Clearfil Esthetic Cement was employed as a control material. Six specimens for each resin cement were used to determine flexural strength, elastic modulus, and resilience according to ISO specification #4049. Ten specimens for each resin cement were used to determine the wear characteristics using an impact-sliding wear testing apparatus. Wear was generated using a stainless-steel ball bearing mounted inside a collet assembly. The maximum facet depth and volume loss were determined using a noncontact profilometer in combination with confocal laser scanning microscopy. Data were evaluated using analysis of variance followed by the Tukey honestly significantly different test (α=0.05). The flexural strength of the resin cements ranged from 68.4 to 144.2 MPa; the elastic modulus ranged from 4.4 to 10.6 GPa; and the resilience ranged from 4.5 to 12.0 MJ/m3. The results for the maximum facet depth ranged from 25.2 to 235.9 μm, and volume loss ranged from 0.0107 to 0.5258 mm3. The flexural properties and wear resistance were found to vary depending upon the self-adhesive resin cement tested. The self-adhesive cements tended to have lower mechanical properties than the conventional resin cement. All self-adhesive resin cements, apart from G-CEM LinkAce, demonstrated significantly poorer wear resistance than did the conventional resin cement.

Effect of Filler Content and Waiting time Before Light-Curing on Mechanical Properties of Dual-Cured Cement

2020 ◽  
Vol 2 (1) ◽  
pp. 45-52
Author(s):  
Ana C. de Assunção Oliveira ◽  
Sandro Griza ◽  
Rafael R. de Moraes ◽  
André L. Faria-e-Silva
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Waiting Time ◽  
Filler Content ◽  
Bending Test ◽  
Resin Cements ◽  
Three Point Bending ◽  
Light Curing ◽  
Curing Procedure

Objective:: To investigate the effect of filler content and the time spent before light-curing on mechanical properties of dual-cured cement. Methods:: Experimental dual-cured resin cements were formulated with 60, 65 or 68wt% of filler. The viscosity of experimental cement was measured using a digital viscometer. Bar-shaped specimens (25 x 2 x 2 mm) were fabricated, while the light-curing was started immediately or 5 minutes after the insertion of cement into the mold (n = 7). A three-point bending test was performed and the values of flexural strength and elastic modulus were measured. The Vickers hardness of fractured specimens was measured on the surface of the cement. Data from viscosity were submitted to oneway ANOVA, while the data from mechanical properties were analyzed by two-way ANOVA. All pair-wise comparisons were performed using Tukey’s test (α = 0.05). Results:: The experimental cement with 68wt% of filler showed the highest viscosity and those with 60wt% showed the the lowest viscosity. Irrespective of the time spent before light-curing, the cement with 65wt% of filler presented the highest values of flexural strength and elastic modulus. The addition of 60wt% of filler resulted in the lowest elastic modulus, while 68wt% of filler resulted in lowest flexural strength. Regarding the hardness, the cement with 68wt% of filler showed the highest values, while there was no difference between 60 and 65wt% of filler. Conclusion:: Filler content affected the mechanical properties of the experimental cement and this effect did not depend on the waiting time before the light-curing procedure.

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.

Delayed Photoactivation of Dual-cure Composites: Effect on Cuspal Flexure, Depth-of-cure, and Mechanical Properties

2019 ◽  
Vol 44 (2) ◽  
pp. E97-E104 ◽  
Author(s):  
KO Hughes ◽  
KJ Powell ◽  
AE Hill ◽  
D Tantbirojn ◽  
A Versluis
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Degree Of Cure ◽  
Bending Tests ◽  
Depth Of Cure ◽  
Four Point Bending ◽  
Tooth Surfaces

SUMMARY Objectives: This study tested whether delayed photoactivation could reduce shrinkage stresses in dual-cure composites and how it affected the depth-of-cure and mechanical properties. Methods and Materials: Two dual-cure composites (ACTIVA and Bulk EZ) were subjected to two polymerization protocols: photoactivation at 45 seconds (immediate) or 165 seconds (2 minutes delayed) after extrusion. Typodont premolars with standardized preparations were restored with the composites, and cuspal flexure caused by polymerization shrinkage was determined with three-dimensional scanning of the external tooth surfaces before restoration (baseline) and at 10 minutes and one hour after photoactivation. Bond integrity (intact interface) was verified with dye penetration. Depth-of-cure was determined by measuring Vickers hardness through the depth at 1-mm increments. Elastic modulus and maximum stress were determined by four-point bending tests (n=10). Results were analyzed with two- or three-way analysis of variance and pairwise comparisons (Bonferroni; α=0.05). Results: Delayed photoactivation significantly reduced cuspal flexure for both composites at 10 minutes and one hour (p≤0.003). Interface was >99% intact in every group. Depth-of-cure, elastic modulus, and flexural strength were not significantly different between the immediate and delayed photoactivation (p>0.05). The hardness of ACTIVA reduced significantly with depth (p<0.001), whereas the hardness of Bulk EZ was constant throughout the depth (p=0.942). Conclusions: Delayed photoactivation of dual-cure restorative composites can reduce shrinkage stresses without negatively affecting the degree-of-cure or mechanical properties (elastic modulus and flexural strength).

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 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.

scholarly journals Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites

2017 ◽  
Vol 28 (6) ◽  
pp. 726-730 ◽  
Author(s):  
Caio Vinícius Signorelli Grohmann ◽  
Eveline Freitas Soares ◽  
Eduardo José Carvalho Souza-Junior ◽  
William Cunha Brandt ◽  
Regina Maria Puppin-Rontani ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Tertiary Amine ◽  
Water Sorption ◽  
Water Solubility ◽  
Distilled Water ◽  
Resin Composites ◽  
Amine Concentration ◽  
One Way Anova

Abstract The aim in this study was to evaluate the influence of different ratio of camphorquinone/tertiary amine concentration on the flexural strength (FS), elastic modulus (EM), degree of conversion (DC), yellowing (YL), water sorption (WS) and water solubility (WSL) of experimental composites. Thus, acrylate blends were prepared with different camphorquinone (CQ) and amine (DABE) concentrations and ratios by weight: (CQ/DABE%): 0.4/0.4% (C1), 0.4/0.8% (C2), 0.6/0.6% (C3), 0.6/1.2% (C4), 0.8/0.8% (C5), 0.8/1.6% (C6), 1.0/1.0% (C7), 1.0/2.0% (C8), 1.5/1.5% (C9), 1.5/3.0% (C10). For the FS and EM, rectangular specimens (7x2x1 mm, n=10) were photo-activated by single-peak LED for 20 s and tested at Instron (0.5 mm/min). Then, the same specimens were evaluated by FTIR for DC measurement. For YL, disks (5x2 mm, n=10) were prepared, light-cured for 20 s and evaluated in spectrophotometer using the b aspect of the CIEL*a*b* system. For WS and WSL, the volume of the samples was calculated (mm³). For WS and WSL, composites disks (5x0.5 mm, n=5) were prepared. After desiccation, the specimens were stored in distilled water for 7 days and again desiccated, in order to measure the WS and WSL. Data were submitted to one-way ANOVA and Tukey’s test (5%). The groups C8, C9 and C10 showed higher DC, EM and YL means, compared to other composites. Therefore, the FS and WS values were similar among all groups. Also, C1, C2 and C3 presented higher WSL in 7 days, compared to other composites. In general, higher concentrations of camphorquinone promoted higher physical-mechanical properties; however, inducing higher yellowing effect for the experimental composites

Microleakage of All-ceramic Crowns Using Self-etching Resin Luting Agents

2008 ◽  
Vol 33 (4) ◽  
pp. 392-399 ◽  
Author(s):  
C. P. Trajtenberg ◽  
S. J. Caram ◽  
S. Kiat-amnuay
Keyword(s):  
Clinical Relevance ◽  
The Self ◽  
Resin Cements ◽  
Adhesive Resin ◽  
Luting Agents ◽  
Relyx Unicem ◽  
All Ceramic ◽  
Ceramic Crowns ◽  
Die Spacer

Clinical Relevance Among the self-adhesive resin cements, Panavia F 2.0 demonstrated less microleakage than RelyX Unicem or Multilink, whether or not a die spacer technique was used.

Effect of SiC Additions on Microstructure Evolution and Mechanical Properties of W-Based Composite Prepared by Arc-Melting

2019 ◽  
Vol 944 ◽  
pp. 531-536
Author(s):  
Ke Jia Kang ◽  
Peng Fan ◽  
Jian Zhang ◽  
Qiang Guo Luo ◽  
Qiang Shen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flexural Strength ◽  
Microstructure Evolution ◽  
Small Angle ◽  
The Self ◽  
Melting Method ◽  
Arc Melting ◽  
Multi Phase ◽  
Strength And Ductility

In this study, the W-Si-C multi-phase composites were fabricated by an arc melting method. With addition of SiC, the grain size of W is obviously reduced, and the small angle misorientation becomes dominate, which is beneficial for the improvement of deformability. The effects of SiC additions (from 0.5 to 3wt%) on the microstructure and mechanical properties are mainly investigated. With 1 wt% SiC addition, the flexural strength reaches the highest value. The self-generation of W5Si3 may enhance the strength and ductility, but too much W5Si3 exists as brittle BP (Brittle to Plastic) microstructure. The highest flexural strength is obtained at approximately 1 vol% W5Si3.

Evaluation of Relations among Basic Mechanical Properties of Concrete with Machine-Made Sand

2011 ◽  
Vol 418-420 ◽  
pp. 441-444 ◽  
Author(s):  
Feng Lan Li ◽  
Yan Zeng ◽  
Chang Yong Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Rough Surface ◽  
Design Code ◽  
Ordinary Concrete ◽  
Axial Compressive Strength ◽  
Different Characteristics

Due to many different characteristics such as irregular polygon particle with pointed edges, rough surface and larger content of stone powder, machine-made sand has ignorable effects on the properties of concrete. As the basis for the design of concrete structures, the relations among the basic mechanical properties of concrete such as compressive strength, tensile strength, flexural strength and elastic modulus should be clearly understood. This paper summarizes the test data from the published references, and discusses the relations among these properties by statistical analyses compared with those of ordinary concrete. The results show that the axial compressive strength and the tensile strength can be prospected by the same formulas of ordinary concrete specified in current Chinese design code, but the prospected tensile strength should multiply a reducing coefficient when the strength grade of concrete is lower than C30. The elastic modulus of concrete with machine-made sand is larger than that of ordinary concrete, which should be prospect by the formula in this paper. Meanwhile, the formula of flexural strength is suggested.

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