scholarly journals An in vitro Evaluation of Diametral Tensile Strength and Flexural Strength of Nanocomposite vs Hybrid and Minifill Composites cured with Different Light Sources (QTH vs LED)

2013 ◽  
Vol 14 (1) ◽  
pp. 84-89
Author(s):  
K Venkata Srikanth ◽  
Surendra Nath Garapati ◽  
Priyadarshini LNU ◽  
Piyush Raturi ◽  
Dinesh Shetty
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
New Technology ◽  
Testing Machine ◽  
Light Sources ◽  
Soft Start ◽  
Two Samples ◽  
Nanocomposite System ◽  
Diametral Tensile Strength

ABSTRACT Background Composites always remained the target of discussion due to lot of controversies around it. Mechanical properties are one of them. With the introduction of new technology and emergence of various composites which combine superior strength and polish retention, nanocomposites have led to a new spark in the dentistry. A recent curing unit LED with various curing modes claims to produce higher degree of conversion. The aim of this study was to evaluate the diametral tensile strength and flexural strength of nanocomposite, hybrid and minifill composites cured with different light sources (QTH vs LED). Materials and methods Seventy-two samples were prepared using different specially fabricated teflon molds, 24 samples of each composite were prepared for the diametral tensile strength (ADA specification no. 27) and the flexural strength (ISO 4049) of the 12 samples, six were cured with LED (Soft Start curing profile) and other six with QTH curing light and tested on a universal testing machine. Results The nanocomposite had highest diametral tensile strength and flexural strength which were equivalent to the hybrid composite and superior than the minifill composite. Conclusion With the combination of superior esthetics and other optimized physical properties, this novel nanocomposite system would be useful for all posterior and anterior applications. How to cite this article Garapati SN, Priyadarshini, Raturi P, Shetty D, Srikanth KV. An in vitro Evaluation of Diametral Tensile Strength and Flexural Strength of Nanocomposite vs Hybrid and Minifill Composites cured with Different Light Sources (QTH vs LED). J Contemp Dent Pract 2013;14(1):84-89.

Diametral Tensile Strength and Reflectance Evaluation of Dental Composite Prototype Using Modified Dental Composite Procedures

2019 ◽  
Vol 829 ◽  
pp. 100-107
Author(s):  
Renny Febrida ◽  
Wafa Sahilah ◽  
Sashya Adriana ◽  
Nina Djustiana ◽  
Elin Karlina ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Sol Gel ◽  
Testing Machine ◽  
Dental Restoration ◽  
Dental Composite ◽  
Resin Matrix ◽  
Two Samples ◽  
Group A ◽  
Different Thickness ◽  
Diametral Tensile Strength

Dental composite is used to restore disease or fracture tooth structure and modify tooth shape as well as color in order to enhance the aesthetic properties. This restoration should possess sufficient strength and translucency at the same time. Diametral tensile strength and reflectance of dental composite were related to the selection of three main components; filler, coupling agent and resin matrix. Quarsi-experimental. This study was a follow-up study whereby the filler silica-zirconia-alumina system were synthesized by sol-gel technique with precursors composition ratio 70:20:10. The surface of subsequent filler were modified by 3-mercaptoppropyltrimethoxysilane (MPTMS) and aminopropyltrimethoxysilane (APTES) then becoming group A and B respectively. In order to prepared the dental composite, acetone was used to reduce the viscosity of Bisphenol A Glycidyl Methacrylate (BisGMA) thus enable introducing more content of filler into resin matrix. Phase of crystalline and particle morphology were identified by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) consecutively. Universal Testing Machine (Lloyd) with crosshead speed 1mm/min was used to evaluate diametral tensile strength between two samples group. Dental composite contain filler-MPTMS coated were continuing tested to measure the reflectance values. Disc of each samples were prepared (n=3) with different thickness (1.5 mm and 3 mm) and same diameter (20 mm). Both diametral tensile strength and reflectance evaluation data were analysis by t-test unpaired. The result showed no statistically significant differences in diametral tensile strength between group A (47,6548 MPa) and B (41,4265 MPa). Reflectance evaluation also exhibited no statistically significant differences in dental composite contain filler-coated MPTMS with different thickness. Dental composite prototype based on diametral tensile strength and reflectance evaluation were potential to be used as alternative dental restoration.

scholarly journals Compressive and diametral tensile strength of glass ionomer cements

2004 ◽  
Vol 12 (4) ◽  
pp. 344-348 ◽  
Author(s):  
Eduardo Bresciani ◽  
Terezinha de Jesus Esteves Barata ◽  
Ticiane Cestari Fagundes ◽  
Akimi Adachi ◽  
Marina Martins Terrin ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Testing Machine ◽  
Glass Ionomer Cement ◽  
Mean Value ◽  
Atraumatic Restorative Treatment ◽  
Glass Ionomer ◽  
Restorative Treatment ◽  
Significant Difference ◽  
The Mean ◽  
Diametral Tensile Strength

The aim of this study was to compare, in different periods of time, the compressive and diametral tensile strength of a traditional high viscous glass ionomer cement: Fuji IX (GC Corporation), with two new Brazilian GIC's: Vitro-Molar (DFL) and Bioglass R (Biodinamica), all indicated for the Atraumatic Restorative Treatment (ART) technique. Fifteen disk specimens (6.0mm diameter x 3.0mm height) for the diametral tensile strength (DTS) test and fifteen cylindrical specimens (6.0mm diameter x 12.0mm height) for the compressive strength (CS) test were made of each GIC. Specimens were stored in deionized water at 37º C and 100% of humidity in a stove until testing. Five specimens of each GIC were submitted to CS and DTS test in each period, namely 1 hour, 24 hours and 7 days. The specimens were tested in a testing machine (Emic) at a crosshead speed of 1.0mm/min for CS and 0.5mm/min for the DTS test until failure occurred. The data were submitted to two-way ANOVA and Tukey tests (alpha=0.05). The mean CS values ranged from 42.03 to 155.47MPa and means DTS from 5.54 to 13.72 MPa, with test periods from 1h to 7 days. The CS and DTS tests showed no statistically significant difference between Fuji IX and Vitro Molar, except for CS test at 1-hour period. Bioglass R had lowest mean value for CS of the cements tested. In DTS test Bioglass R presented no statistically significant differences when compared with all others tested GICs at 1-hour period and Bioglass R presented no difference at 24-hour and 7-day periods when compared to Vitro-Molar. Further studies to investigate other physical properties such as fracture toughness and wear resistance, as well as chemical composition and biocompatibility, are now needed to better understand the properties of these new Brazilian GIC's.

scholarly journals A COMPARATIVE EVALUATION OF MICROLEAKAGE, COMPRESSIVE STRENGTH, FLEXURAL STRENGTH AND FLUORIDE RELEASE OF ZIRCONOMER AND KETAC SILVER: AN IN VITRO STUDY.

2020 ◽  
Vol 9 (4) ◽  
Author(s):  
CHARANTEJA VEMAGIRI ◽  
Uloopi KS ◽  
Vinay Chandrappa ◽  
Anusha Ch
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Testing Machine ◽  
In Vitro Study ◽  
Biological Properties ◽  
T Test ◽  
Fluoride Release ◽  
Restorative Material ◽  
Glass Ionomer

Background: A successful restorative material forms a better adhesion, resist the microleakage and releases fluoride. However, existing glass ionomer cements cannot be used as a posterior restorative material in stress bearing areas. A new ionomer called Zirconomer, zirconia reinforced glass ionomer claims to exhibit high physical and biological properties. Aim: To assess and compare the microleakage, compressive strength, flexural strength and fluoride release from zirconomer with ketac silver. Materials & Methods: On twenty caries free premolar teeth (10 per each group), a class v cavity was restored with zirconomer and ketac silver. The microleakage was assessed using dye penetration test and stereomicroscope. The compressive and flexural strengths of these materials were measured using Instron Universal testing machine. The amount of fluoride released from the modified ionomers at pH 5 and pH 7 was estimated using Orion fluoride specific electrode. The obtained data was then subjected to statistical analysis. Results: Data was analysed using paired t-test for intergroup comparisons and unpaired t-test for intragroup comparisons. The overall microleakage (0.5±0.48) of zirconomer was significantly less (p=0.000) compared to ketac silver (1.9±0.83). Zirconomer demonstrated a significant higher compressive strength (330.25±60.14), flexural strength (33.058±2.36) than ketac silver (p= 0.000). Zirconomer demonstrated high fluoride release from day 1 to day 7 at both pH 5 and pH 7. Conclusion: Zirconomer demonstrated better physical and biological properties compared with ketac silver.

scholarly journals Mechanical Integrity of Hemodialysis Catheters after Exposure to a Novel Catheter Lock Solution

2010 ◽  
Vol 31 (11) ◽  
pp. 1124-1129 ◽  
Author(s):  
Saima Aslam ◽  
Rabih O. Darouiche
Keyword(s):  
Tensile Strength ◽  
Testing Machine ◽  
The Novel ◽  
Yield Strain ◽  
Time Intervals ◽  
Mechanical Integrity ◽  
Industry Standards ◽  
Lock Solution ◽  
Catheter Lock

Objective.To examine the mechanical integrity of hemodialysis catheters after exposure to the combination of N-acetylcysteine, ti-gecycline, and heparin, compared with that of catheters exposed to heparin alone.Methods.We used 3 types of hemodialysis catheters: polyurethane, silicone, and carbothane catheters. Catheter segments were incubated in vitro for various time intervals of up to 2 weeks either in a novel catheter lock solution (novel CLS), which consisted of N-acetylcysteine, tigecycline, and heparin, or in heparin alone (as a control). At the time of testing, each segment was rinsed and cut longitudinally into 2 sections. All catheter sections were scanned using an optical dissecting microscope to check for surface abnormalities and to measure wall thickness. We also carried out tensile strength testing of another set of catheters using a universal testing machine. Tested parameters included stress at yield, strain at yield, stress at break, strain at break, modulus of elasticity, and force at break.Results.The surfaces of catheters in both groups appeared similar by microscopy. The mean thickness of the catheter wall was not significantly different for the catheters exposed to the novel CLS and the catheters exposed to heparin (P >.05). Results for most of the tensile strength parameters tested were similar in the 2 groups of catheters at the end of 2 weeks of incubation. In particular, the force-at-break value of all tested catheters remained much greater than that recommended by industry standards.Conclusions.The use of the novel catheter lock solution did not impair the mechanical integrity or increase the propensity for fracture of hemodialysis catheters.

Comparison between traditional and alternative biocompatible welding techniques used in orthodontic devices

2020 ◽  
pp. 146531252097240
Author(s):  
Fernanda de Souza Henkin ◽  
Luciane Macedo de Menezes ◽  
Berenice Anina Dedavid ◽  
Cátia Abdo Quintão
Keyword(s):  
Tensile Strength ◽  
Laser Welding ◽  
Mechanical Performance ◽  
Steel Wire ◽  
Testing Machine ◽  
Mean Values ◽  
Welding Spot ◽  
Microstructural Morphology ◽  
Orthodontic Devices

Objective: To compare the mechanical strength of joints made by conventional soldering with those made by alternative, more biocompatible, methods (spot, tungsten inert gas [TIG] and laser welding), and to compare the microstructural morphology of wires welded with these techniques. Design: In vitro, laboratory study. Methods: Forty stainless-steel wire segments with 0.8-mm diameter were joined by silver soldering, spot, laser and TIG welding. Ten specimens were produced for each one. Tensile strength test was performed 24 h after welding on the Emic DL2000™ universal testing machine, using a load cell of 1000 N with a crosshead speed of 10 mm/min. Results: The highest tensile strength mean values were obtained with silver soldering (532 N), next were laser (420 N), spot (301 N) and TIG (296 N) welding. Statistically significant differences were observed between the groups; the Dunn post-hoc test revealed differences between laser and spot welding ( p=0.046), laser and TIG ( p = 0.016), spot and silver ( p <0.001), and silver and TIG ( p <0.001). Conclusion: Laser welding strength is high, and comparable to silver welding. Spot and TIG techniques present comparable and significantly lower strengths. The four methods presented resistance values compatible with orthodontic use. The microstructural morphology is different for each technique. The association between the mechanical performance and the microstructure evaluation shows that laser presented the highest quality joint.

scholarly journals A Comparative Evaluation of Flexural Strength of Commercially Available Acrylic and Modified Polymethylmethacrylate: An in vitro Study

2013 ◽  
Vol 14 (1) ◽  
pp. 80-83 ◽  
Author(s):  
Naveen S Yadav ◽  
Teerthesh Jain ◽  
Amrita Pandita ◽  
SMA Feroz ◽  
UK Kartika ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Methacrylic Acid ◽  
Comparative Evaluation ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Bending Test ◽  
Control Group ◽  
Diabetic Patients ◽  
Denture Stomatitis

ABSTRACT Aim The purpose of this study was to evaluate and compare the flexural strength of commercially available acrylic (trevalone) and modified polymethylmethacrylate (PMMA). Materials and methods Four groups were tested; Group 1— control group regular MMA, group 2—2% methacrylic acid, 88% MMA, group 3—16% methacrylic acid, 84% MMA group 4— 20% methacrylic acid, 80% MMA 15 resin specimens of each group were polymerized. After processing, the specimens were subjected for flexural strength testing using three point bending test in a Universal Testing Machine. All data was statistically analyzed with one-way ANOVA, differences within the groups were analyzed by Scheffe's analysis. Results As the ratio of incorporated methacrylic acid to PMMA increased, the flexural strength decreased. Analysis of data revealed a significant decrease in flexural strength of specimens (p < 0.000) after incorporation of 12%, 16%, 20% methacrylic acid to heat polymerized acrylic resin, when compared with the control group. Lowest flexural strength was observed with specimens containing 20% methacrylic acid and highest flexural strength was observed with specimens containing conventional monomer without methacrylic acid. Conclusion It was observed that as the concentration of methacrylic acid in heat polymerized acrylic resin increases, the flexural strength decreases. Lowest flexural strength was observed with specimens containing 20% methacrylic acid and highest flexural strength was observed with specimens containing conventional monomer without methacrylic acid. Clinical significance The major advantages of addition of methacrylic acid to polymethylmethacrylate could be for the elderly people with restricted manual dexterity or cognitive disturbances, especially for patients who do not follow an adequate denture cleansing protocol and diabetic patients who are more susceptible for denture stomatitis. How to cite this article Jain T, Yadav NS, Pandita A, Feroz SMA, Kartika UK, Singh PP. A Comparative Evaluation of Flexural Strength of Commercially Available Acrylic and Modified Polymethylmethacrylate: An in vitro Study. J Contemp Dent Pract 2013;14(1):80-83.

scholarly journals Evaluation of Different in Vitro Testing Methods for Mechanical Properties of Veneer Ceramics/ Евалуација На Тестовите In Vitro За Одредување На Механичките Особини На Порцеланските Маси За Фасетирање

PRILOZI ◽  
2015 ◽  
Vol 36 (1) ◽  
pp. 225-230 ◽  
Author(s):  
Aneta Mijoska ◽  
Mirjana Popovska
Keyword(s):  
Flexural Strength ◽  
Mechanical Characteristics ◽  
Testing Machine ◽  
In Vitro Testing ◽  
Biaxial Test ◽  
Testing Methods ◽  
Dental Ceramic ◽  
Universal Testing ◽  
Biaxial Tests

Abstract Metal-ceramic and all-ceramic prosthetic restorations in the patient mouth are often damaged by esthetic and functional problems that reduce their success and longevity. Аim: To evaluate methods for testing mechanical characteristics of dental ceramics through analysis of different testing methods. Material and methods: Dental ceramic materials are tested with in vivo and in vitro methods for their most important mechanical characteristics: hardness, toughness, flexural strength and abrasion. In vitro testing methods are faster and more efficient, without subjective factors from the patient according to ISO standards. Testing is done with universal testing machines, like Zwick 1445, Universal Testing Machine (Zwick DmbH & Co.KG, Ulm, Germany), Instron 4302 (Instron Corporation, England), MTS Sintech ReNew 1123 or in oral chewing simulators. Results: According to the testing results, flexure strength is one of the most important characteristic of the dental ceramic to be tested, by the uniaxial and biaxial tests. Uniaxial tests three-point and four-point flexure are not most appropriate because the main stress on the lower side of the tested specimens is tension that causes beginning fractures at the places with superficial flow. Uniaxial results for flexural strength are lower than actual force, while with biaxial test defects and flows on the edges of tested specimens are not directly loaded. Conclusion: Biaxial flexural method has advantages over uniaxial because of real strength results, but also for simple shape and preparing of the testing specimens.

scholarly journals Influence of Light-curing Parameters on Biofilm Development and Flexural Strength of a Silorane-based Composite

2016 ◽  
Vol 41 (2) ◽  
pp. 219-227 ◽  
Author(s):  
E Brambilla ◽  
A Ionescu ◽  
G Cazzaniga ◽  
M Ottobelli
Keyword(s):  
Flexural Strength ◽  
Laser Scanning ◽  
Testing Machine ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Curing Time ◽  
Two Samples ◽  
Significant Difference ◽  
Light Curing ◽  
Biofilm Development

SUMMARYObjectives: The aim of this study was to evaluate the differences in biological and mechanical performances of a silorane-based and a methacrylate-based composite. Another aim was to assess the influence of light-curing time and light-curing intensity on in vitro biofilm formation and flexural strength of the two tested composites.Methods: Experiment 1: 432 specimens obtained from a silorane-based composite and from a standard methacrylate-based composite were divided into six groups and light-cured for 10, 20, 30, 40, 60, or 80 seconds, using one of two light-curing intensities, 400 mW/cm2 or 800 mW/cm2. At 24 hours, a monospecific Streptococcus mutans biofilm adherent to the surfaces of the samples was obtained. Then, a colorimetric technique (MTT assay) was used to evaluate the adherent viable biomass. Two samples per group were observed using confocal laser scanning microscopy. Analysis of variance (ANOVA) and Tukey tests were used to analyze the results (p&lt;0.05). Experiment 2: 192 bar-shaped specimens were obtained and light-cured as in the previous experiment. A three-point bend test using a universal testing machine was performed to obtain flexural strength values. ANOVA and Tukey tests were used to analyze the results (p&lt;0.05).Results: In experiment 1, a highly significant difference (p&lt;0.0001) in biofilm development was shown between silorane-based and methacrylate-based composites. In fact, the silorane-based composite exhibited better biological performance. Significant differences were also found between the two light-curing intensities (p&lt;0.018) and for curing times (p&lt;0.0001): silorane-based composite light-cured for 80 seconds at 800 mW/cm2 light-curing intensity showed the lowest biofilm development. In experiment 2, a significant difference in flexural strength (p&lt;0.0318) was only found between the different composites. Nevertheless, both resin composites showed flexural strength values in accordance with International Organization for Standardization guidelines even after 10 seconds of light-curing time.Conclusions: Silorane-based composite was less prone to biofilm development compared with a methacrylate-based composite. Acceptable flexural strength values for both composites were obtained after 10 seconds of light-curing time.

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