scholarly journals Surface Integrity of Dimethacrylate Composite Resins with Low Shrinkage Comonomers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1614
Author(s):  
Jingwei He ◽  
Sufyan Garoushi ◽  
Eija Säilynoja ◽  
Pekka Vallittu ◽  
Lippo Lassila
Keyword(s):  
Surface Integrity ◽  
Color Change ◽  
Negative Impact ◽  
Surface Hardness ◽  
Triethylene Glycol ◽  
Weight Fraction ◽  
Composite Resins ◽  
Resin Matrix ◽  
Study Results ◽  
Chewing Simulator

The goal of current research was to investigate the influence of adding low shrinkage “Phene” like comonomers hexaethylene glycol bis(carbamate-isoproply-α-methylstyrene) (HE-Phene) and triethylene glycol bis(carbamate-isoproply-α-methylstyrene) (TE-Phene) on the surface and color characteristics of composite resin. A range of weight fractions (0, 10, 20, 30, 40 wt.%) of HE/TE-Phene monomers were mixed with bisphenol A glycidyl methacrylate (GMA)/triethylene glycol dimethacrylate (TEGDMA) monomer. Experimental composite resins were made by mixing 71 wt.% of silica fillers to 29 wt.% of the resin matrix. A Vickers indenter and glossmeter were used for testing surface hardness (SH) and gloss (SG) at 60°. A chewing-simulator was used to evaluate the surface wear after 15,000 cycles. Color change (∆E) and translucency parameter (TP) were measured using a spectrophotometer. Data showed that HE/TE-Phene monomer had no negative impact (p > 0.05) on surface gloss, wear, color change and translucency of experimental composite resins. Surface hardness was in a reducing direction with the increas in HE/TE-Phene weight fraction (p < 0.05). The study results suggested that incorporating HE/TE-Phene monomers up to 30 wt.% with Bis-GMA/TEGDMA resin did not negatively influence the surface integrity of composite resins except for SH.

scholarly journals Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

2020 ◽  
Vol 16 ◽  
pp. 2687-2700
Author(s):  
Lena Reinke ◽  
Julia Bartl ◽  
Marcus Koch ◽  
Stefan Kubik
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Limit Of Detection ◽  
Negative Impact ◽  
Optical Detection ◽  
Relative Number ◽  
Triethylene Glycol ◽  
Binding Mode ◽  
Metal Centers ◽  
Mixed Monolayer

Gold nanoparticles covered with a mixture of ligands of which one type contains solubilizing triethylene glycol residues and the other peripheral zinc(II)–dipicolylamine (DPA) complexes allowed the optical detection of hydrogenphosphate, diphosphate, and triphosphate anions in water/methanol 1:2 (v/v). These anions caused the bright red solutions of the nanoparticles to change their color because of nanoparticle aggregation followed by precipitation, whereas halides or oxoanions such as sulfate, nitrate, or carbonate produced no effect. The sensitivity of phosphate sensing depended on the nature of the anion, with diphosphate and triphosphate inducing visual changes at significantly lower concentrations than hydrogenphosphate. In addition, the sensing sensitivity was also affected by the ratio of the ligands on the nanoparticle surface, decreasing as the number of immobilized zinc(II)–dipicolylamine groups increased. A nanoparticle containing a 9:1 ratio of the solubilizing and the anion-binding ligand showed a color change at diphosphate and triphosphate concentrations as low as 10 μmol/L, for example, and precipitated at slightly higher concentrations. Hydrogenphosphate induced a nanoparticle precipitation only at a concentration of ca. 400 μmol/L, at which the precipitates formed in the presence of diphosphates and triphosphates redissolved. A nanoparticle containing fewer binding sites was more sensitive, while increasing the relative number of zinc(II)–dipicolylamine complexes beyond 25% had a negative impact on the limit of detection and the optical response. Transmission electron microscopy provided evidence that the changes of the nanoparticle properties observed in the presence of the phosphates were due to a nanoparticle crosslinking, consistent with the preferred binding mode of zinc(II)–dipicolylamine complexes with phosphate anions which involves binding of the anion between two metal centers. This work thus provided information on how the behavior of mixed monolayer-protected gold nanoparticles is affected by multivalent interactions, at the same time introducing a method to assess whether certain biologically relevant anions are present in an aqueous solution within a specific concentration range.

Poly(methyl methacrylate) Grafted Silica Nanoparitcles via ATRP for Bis-GMA/TEGDMA Dental Restorative Composite Resins

2013 ◽  
Vol 647 ◽  
pp. 46-52 ◽  
Author(s):  
Hong Zhong ◽  
Xue Gang Zhou ◽  
Qing Cai ◽  
Xiao Ping Yang
Keyword(s):  
Methyl Methacrylate ◽  
Silica Nanoparticles ◽  
Composite Resin ◽  
Triethylene Glycol ◽  
Composite Resins ◽  
Resin Matrix ◽  
Modify Silica ◽  
Triethylene Glycol Dimethacrylate ◽  
Poly Methyl Methacrylate ◽  
Dental Restorative

To improve the dispersibility of silica nanoparticles in dimethacrylate-based dental restorative composite resins, an efficient way was proposed to surface modify silica nanoparticles with polymer grafts. Firstly, silica nanoparticles reacted with 3-aminopropyl-triethoxysilane and 2-bromoisobutyryl bromide to obtain silica with the derived atom transfer radical polymerization (ATRP) initiators, which subsequently initiated the polymerization of methyl methacrylate to fabricate poly(methyl methacrylate) grafted silica nanohybrids. These nanohybrids could be well dispersed into bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) resin and had good interfacial bonding to the resin matrix. With the addition of modified silica nanopaticles, the flexural strength of the photo-cured composite resin was significantly increased in comparison with that of the unmodified group.

A dental filling composite resin restorative with improved antibacterial function and hardness

2020 ◽  
Vol 55 (2) ◽  
pp. 159-168
Author(s):  
Gulsah Caneli ◽  
Yong Chen ◽  
Na Sungsoo ◽  
Gregory G Anderson ◽  
Dong Xie
Keyword(s):  
Particle Size ◽  
Antibacterial Activity ◽  
Composite Resin ◽  
Filler Content ◽  
Negative Impact ◽  
Surface Hardness ◽  
Filler Loading ◽  
Composite Resins ◽  
Dental Composite ◽  
Almost All

A novel antimicrobial dental composite resin has been developed and evaluated. Alumina filler particles were covalently coated with an antibacterial resin and blended into a composite resin formulation. Surface hardness and bacterial viability were used to evaluate the modified composite resin. Results showed that almost all the modified composite resins exhibited higher antibacterial activity along with improved surface hardness, as compared to unmodified one. Effects of antibacterial moiety content on the modified fillers, modified alumina particle size and loading, and total filler content were investigated. It was found that increasing antibacterial moiety content, particle size and loading of the modified filler, and total filler content generally increased surface hardness. Increasing antibacterial moiety, filler loading and total filler content increased antibacterial activity. On the other hand, increasing particle size showed a negative impact on antibacterial activity. The leaching tests indicate that the modified experimental composite resin showed no leachable antibacterial component to bacteria and 3T3 mouse fibroblasts.

scholarly journals A Low-Viscosity BisGMA Derivative for Resin Composites: Synthesis, Characterization, and Evaluation of Its Rheological Properties

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 338
Author(s):  
Ali Alrahlah ◽  
Abdel-Basit Al-Odayni ◽  
Haifa Fahad Al-Mutairi ◽  
Bashaer Mousa Almousa ◽  
Faisal S. Alsubaie ◽  
...  
Keyword(s):  
Substantial Reduction ◽  
Triethylene Glycol ◽  
High Viscosity ◽  
Resin Matrix ◽  
Resonance Spectroscopy ◽  
Dental Resin ◽  
Triethylene Glycol Dimethacrylate ◽  
Oh Groups ◽  
Low Viscosity ◽  
13C Nuclear Magnetic Resonance

This study aimed to synthesize new bisphenol A-glycidyl methacrylate (BisGMA) derivatives, targeting a reduction in its viscosity by substituting one of its OH groups, the leading cause of its high viscosity, with a chlorine atom. Hence, this monochloro-BisGMA (mCl-BisGMA) monomer was synthesized by Appel reaction procedure, and its structure was confirmed using Fourier transform infrared spectroscopy, 1H and 13C-nuclear magnetic resonance spectroscopy, and mass spectroscopy. The viscosity of mCl-BisGMA (8.3 Pa·s) was measured under rheometry conditions, and it was found to be more than 65-fold lower than that of BisGMA (566.1 Pa·s) at 25 °C. For the assessment of the viscosity changes of model resins in the presence of mCl-BisGMA, a series of resin matrices, in which, besides BisGMA, 50 wt % was triethylene glycol dimethacrylate, were prepared and evaluated at 20, 25, and 35 °C. Thus, BisGMA was incrementally replaced by 25% mCl-BisGMA to obtain TBC0, TBC25, TBC50, TBC75, and TBC100 blends. The viscosity decreased with temperature, and the mCl-BisGMA content in the resin mixture increased. The substantial reduction in the viscosity value of mCl-BisGMA compared with that of BisGMA may imply its potential use as a dental resin matrix, either alone or in combination with traditional monomers. However, the various properties of mCl-BisGMA-containing matrices should be evaluated.

scholarly journals Influence of Shot Peening on the Isothermal Fatigue Behavior of the Gamma Titanium Aluminide Ti-48Al-2Cr-2Nb at 750 °C

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1083
Author(s):  
Christoph Breuner ◽  
Stefan Guth ◽  
Elias Gall ◽  
Radosław Swadźba ◽  
Jens Gibmeier ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Shot Peening ◽  
Elevated Temperatures ◽  
Stress Amplitude ◽  
Negative Impact ◽  
Fatigue Behavior ◽  
Surface Hardness ◽  
Fatigue Tests ◽  
Positive Effects ◽  
Isothermal Fatigue

One possibility to improve the fatigue life and strength of metallic materials is shot peening. However, at elevated temperatures, the induced residual stresses may relax. To investigate the influence of shot peening on high-temperature fatigue behavior, isothermal fatigue tests were conducted on shot-peened and untreated samples of gamma TiAl 48-2-2 at 750 °C in air. The shot-peened material was characterized using EBSD, microhardness, and residual stress analyses. Shot peening leads to a significant increase in surface hardness and high compressive residual stresses near the surface. Both effects may have a positive influence on lifetime. However, it also leads to surface notches and tensile residual stresses in the bulk material with a negative impact on cyclic lifetime. During fully reversed uniaxial tension-compression fatigue tests (R = −1) at a stress amplitude of 260 MPa, the positive effects dominate, and the fatigue lifetime increases. At a lower stress amplitude of 230 MPa, the negative effect of internal tensile residual stresses dominates, and the lifetime decreases. Shot peening leads to a transition from surface to volume crack initiation if the surface is not damaged by the shots.

Influence of Hydrogen Peroxide Bleaching Gels on Color, Opacity, and Fluorescence of Composite Resins

2012 ◽  
Vol 37 (5) ◽  
pp. 526-531 ◽  
Author(s):  
CRG Torres ◽  
CF Ribeiro ◽  
E Bresciani ◽  
AB Borges
Keyword(s):  
Hydrogen Peroxide ◽  
Composite Resin ◽  
Color Change ◽  
Composite Resins ◽  
Control Group ◽  
Peroxide Bleaching ◽  
Color Changes ◽  
Tukey Test ◽  
Bleaching Gels ◽  
Bleaching Treatment

SUMMARY The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (p&lt;0.05). Color changes were significant for different tested bleaching therapies (p&lt;0.0001), with the greatest color change observed for 35% hydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (p&lt;0.0001) and bleaching therapy (p=0.0016) used. No significant differences in fluorescence between different bleaching gel concentrations were detected by Tukey test. The greatest fluorescence alteration was detected on the brand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration.

scholarly journals The effect of resin shades on microhardness, polymerization shrinkage, and color change of dental composite resins

2009 ◽  
Vol 28 (4) ◽  
pp. 438-445 ◽  
Author(s):  
Tae-Sung JEONG ◽  
Ho-Seung KANG ◽  
Sung-Ki KIM ◽  
Shin KIM ◽  
Hyung-Il KIM ◽  
...  
Keyword(s):  
Color Change ◽  
Composite Resins ◽  
Dental Composite ◽  
Polymerization Shrinkage ◽  
Dental Composite Resins

Surface properties of composite resins with and without fluorides for bracket bonding / Propriedades de superfície de resinas compostas com e sem fluoretos para colagem de suportes

2021 ◽  
Vol 7 (7) ◽  
pp. 67267-67276
Author(s):  
Emillyn Jones Greijal Dias Holanda ◽  
José Guilherme Neves ◽  
Milton Santamaria-Jr ◽  
Silvia Amélia Scudeler Vedovello ◽  
Ana Rosa Costa ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Properties ◽  
Color Change ◽  
Composite Resins ◽  
Hardness Tester ◽  
Significant Difference ◽  
Post Test ◽  
Roughness Analysis ◽  
Diamond Paste ◽  
Penetration Time

The aim of this study was to evaluate the surface properties of orthodontic resins with and without fluoride. Forty disks, measuring 2 mm thick by 6 mm in diameter, were made of 4 bracket-bonding composite resins (n=10): Transbond Plus Color Change-3M/Unitek (TPCC); Transbond XT- 3M/Unitek (TXT), Orthocem -FGM (OC); Orthocem UV Trace-FGM (OCUV). The discs were photoactivated for 40 seconds with irradiance of 450 mW/cm2 and manually polished in sequence by silicon carbide sandpapers with 1200 and 2000 grain size and finished with diamond paste and felt disc. The surface microhardness analysis was performed using a Shimadzu Micro Hardness Tester HMV-2,000 (Shimadzu Corporation, Kyoto, Japan) with a load of 50 gF and a 5 second penetration time. Surface roughness readings were taken using a Surf Corder Roughness Meter (SE 1700- Kosaka, Lisboa-Portugal). For data analysis, ANOVA (one-way) was used, followed by Tukey's post-test (?=0.05). The microhardness results showed a difference (p?0.05) in the means of the orthodontic resins between TPCC and TXT with the other groups. After the surface roughness analysis, the averages showed that TPCC resin showed higher roughness compared to OC and OCUV (p?0.05), and there was no statistical difference with TXT. It was concluded that statistically the composite resins with fluoride showed significant difference regarding hardness and roughness.

Fetomaternal Outcome of Pregnancy with COVID-19: An Observational Study in Tertiary Care Hospitals of Pakistan

2021 ◽  
Vol 15 (6) ◽  
pp. 1903-1906
Author(s):  
Nabila Khan ◽  
Zahra Wasim ◽  
Aesha Sadaf Rizwan ◽  
Afshan Ahmad ◽  
Muhammad Tahir ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Negative Impact ◽  
Heart Defects ◽  
Tertiary Care ◽  
World Health ◽  
Observational Research ◽  
Military Hospital ◽  
Corona Virus ◽  
Study Results ◽  
The World

Background: The new corona virus first appeared in Wuhan, China in December 2019 and has since spread around the world to other countries. The World Health Organization believes that this new CoV-19 epidemic is a public health emergency of international concern (PHEIC) on January 30, 2020Worldwide.The mortality rate of this viral infection ranges from 2% in Pakistan to 14.4% in Italy. Lympopenia, elevated transminase, proteinuria, increased LDH, and C-reactive protein levels are all common laboratory findings in the early stages of the disease. Covid patients have experienced a variety of complications, including extreme pneumonia, ARDS, heart defects, sepsis and septic shock, and respiratory tract super infection. Methodology: This retrospective observational research study was carried out at the Gynecology Unit of MardanMedical Complex, Mardan and Combined Military Hospital, Risalpur for 06 months duration from April 2020 to September 2020. In a pre-constructed data collection form, biochemical and radiological parameters of medical history, test results, symptoms, pregnancy, and neonatal outcomes were noted. Patients treated in an outpatient setting were not included in the study. Results: There were 121 patients in total, with mean age of 27 having standard deviation ± 5, having range 19-40 years. 48.3% pregnant women reported their first pregnancy(primigravida). 51.3% of SARS-Cov-2 were in their 3rd trimester while 34.7% were in their 35-40 weeks of gestational age. Common complications are gestational hypertension (PIH) (16 cases), hypothyroidism (14 cases) and gestational diabetes (GDM) 9 cases. More than half (53%) of patients are asymptomatic. Common symptoms are cough (22%) and fever (11%). The incidence of multiple organ failure was 2% as shown in table 01. Lymphopenia was common (84%). A CT scan of 24 patients showed bilateral invasion. Conclusion: COVID-19 has a negative impact on the foetus, according to our results. Although pregnant women do not seem to be more vulnerable to COVID-19 complications than non-pregnant adults, previous research has suggested that pregnant women could be at higher risk for negative pregnancy outcomes such as preterm birth, foetal pain and respiration, symptoms, and LBW in a newborn baby. Keywords: Corona virus, COVID-19, Pregnancy, Outcome.

scholarly journals Impact of refrigeration on the surface hardness of hybrid and microfilled composite resins

2009 ◽  
Vol 20 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Fernando Henrique Ruppel Osternack ◽  
Danilo Biazzetto de Menezes Caldas ◽  
Rodrigo Nunes Rached ◽  
Sérgio Vieira ◽  
Jeffrey A. Platt ◽  
...  
Keyword(s):  
Room Temperature ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Knoop Hardness ◽  
Composite Resins ◽  
Bottom Surface ◽  
Steel Mold ◽  
Polymerization Condition ◽  
Post Hoc

This in vitro study evaluated the Knoop hardness of the composite resins Charisma® (C) and Durafill VS® (D) polymerized in 3 different conditions: at room temperature (A) (23 ± 1°C); refrigerated at 4 ± 1°C and immediately photo-activated after removal from the refrigerator (0); and, refrigerated at 4 ± 1°C and photo-activated after a bench time of 15 min at room temperature (15). One hundred and twenty specimens (4 mm diameter and 2 mm depth) were made using a stainless steel mold and following manufacturer's instructions. All specimens were tested immediately after polymerization (I) and after 7 days of water storage in the dark at room temperature (7d). The data were subjected to ANOVA and post-hoc Tukey's test (a=0.05). On the top surface, CAI was statistically similar to C15I and DAI to D15I (p>0.05). On the bottom surface, CAI presented higher hardness values when compared to COI and C15I (p<0.05). The D groups showed no significant differences (p>0.05) on the bottom surfaces for any tested polymerization condition. After 7 days of storage, the Knoop hardness decreased significantly (p<0.05) for groups C7d and D7d except for C07d, which was not different from COI at either surface (p>0.05). D07d showed higher Knoop hardness (p<0.05) values on the top surface when compared to the other groups.

Sign in / Sign up

Export Citation Format

Share Document