Contamination of Composite Resin by Glove Powder and Saliva Contaminants: Impact on Mechanical Properties and Incremental Layer Debonding

2015 ◽  
Vol 40 (4) ◽  
pp. 396-402 ◽  
Author(s):  
NM Martins ◽  
GU Schmitt ◽  
HL Oliveira ◽  
MM Madruga ◽  
RR Moraes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Bond Strength ◽  
Mechanical Performance ◽  
Composite Resin ◽  
Flexural Modulus ◽  
Control Group ◽  
Digital Manipulation ◽  
Diametral Tensile Strength

SUMMARY This study investigated the influence of digital manipulation of a composite resin (Z250; 3M ESPE, St Paul, MN, USA) with gloves contaminated with powder and/or human stimulated saliva on the mechanical properties and incremental layer debonding of the restorative. The six groups tested were powdered gloves with or without saliva, powder-free gloves with or without saliva, powdered gloves with saliva cleaned with 70% ethanol, and no digital manipulation or contamination (control). Diametral tensile strength, flexural strength, flexural modulus, and incremental layer shear bond strength were evaluated. Each composite increment was digitally manipulated for 10 seconds. Data from each test were separately analyzed using analysis of variance and the Student-Newman-Keuls test (α=0.05). No significant differences for diametral tensile strength were observed. Manipulation of the composite using powder-free gloves with saliva or using gloves cleaned with ethanol generated higher flexural strength and modulus compared to the other groups. The control group and the group manipulated using powdered gloves with saliva generally showed lower mechanical performances. Lower incremental layer bond strength was observed for the group manipulated with powdered gloves without saliva. The control group and the groups manipulated with powdered gloves with saliva or cleaned with ethanol showed higher shear bond strengths. Most of the failures were cohesive. In conclusion, digital manipulation might be important for the composite resin to achieve better mechanical performance and incremental layer bond strength, provided that the gloves are not contaminated. Cleaning the gloves with ethanol might avoid the negative effects of digital manipulation using contaminated gloves.

Effect of Preheating and Fatiguing on Mechanical Properties of Bulk-fill and Conventional Composite Resin

2019 ◽  
Vol 45 (4) ◽  
pp. 387-395
Author(s):  
AA Abdulmajeed ◽  
TE Donovan ◽  
R Cook ◽  
TA Sulaiman
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Composite Resin ◽  
Statistical Significance ◽  
Composite Resins ◽  
Significant Difference ◽  
Diametral Tensile Strength

Clinical Relevance Bulk-fill composite resins may have comparable mechanical properties to conventional composite resin. Preheating does not reduce the mechanical properties of composite resins. SUMMARY Statement of Problem: Bulk-fill composite resins are increasingly used for direct restorations. Preheating high-viscosity versions of these composites has been advocated to increase flowability and adaptability. It is not known what changes preheating may cause on the mechanical properties of these composite resins. Moreover, the mechanical properties of these composites after mastication simulation is lacking. Purpose: The purpose of this study was to evaluate the effect of fatiguing and preheating on the mechanical properties of bulk-fill composite resin in comparison to its conventional counterpart. Methods and Materials: One hundred eighty specimens of Filtek One Bulk Fill Restorative (FOBR; Bulk-Fill, 3M ESPE) and Filtek Supreme Ultra (FSU; Conventional, 3M ESPE) were prepared for each of the following tests: fracture toughness (International Organization for Standardization, ISO 6872), diametral tensile strength (No. 27 of ANSI/ADA), flexural strength, and elastic modulus (ISO Standard 4049). Specimens in the preheated group were heated to 68°C for 10 minutes and in the fatiguing group were cyclically loaded and thermocycled for 600,000 cycles and then tested. Two-/one-way analysis of variance followed by Tukey Honest Significant Difference (HSD) post hoc test was used to analyze data for statistical significance (α=0.05). Results: Preheating and fatiguing had a significant effect on the properties of both FSU and FOBR. Fracture toughness increased for FOBR specimens when preheated and decreased when fatigued (p=0.016). FOBR had higher fracture toughness value than FSU. Diametral tensile strength decreased significantly after fatiguing for FSU (p=0.0001). FOBR had a lower diametral tensile strength baseline value compared with FSU (p=0.004). Fatiguing significantly reduced the flexural strength of both FSU and FOBR (p=0.011). Preheating had no effect on the flexural strength of either FSU or FOBR. Preheating and fatiguing significantly decreased the elastic modulus of both composite resins equally (p>0.05). Conclusions: Preheating and fatiguing influenced the mechanical properties of composite resins. Both composites displayed similar mechanical properties. Preheating did not yield a major negative effect on their mechanical properties; the clinical implications are yet to be determined.

scholarly journals Assessment of the mechanical properties of glass ionomer cements for orthodontic cementation

2012 ◽  
Vol 17 (6) ◽  
pp. 154-159 ◽  
Author(s):  
Marcel M. Farret ◽  
Eduardo Martinelli de Lima ◽  
Eduardo Gonçalves Mota ◽  
Hugo Mitsuo S. Oshima ◽  
Gabriela Maguilnik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Strength Tests ◽  
Diametral Tensile Strength

OBJECTIVE: To evaluate the mechanical properties of three glass ionomers cements (GICs) used for band cementation in Orthodontics. METHODS: Two conventional glass ionomers (Ketac Cem Easy mix/3M-ESPE and Meron/Voco) and one resin modified glass ionomer (Multi-cure Glass ionomer/3M-Unitek) were selected. For the compressive strength and diametral tensile strength tests, 12 specimens were made of each material. For the microhardness test 15 specimens were made of each material and for the shear bond strength tests 45 bovine permanent incisors were used mounted in a self-cure acrylic resin. Then, band segments with a welded bracket were cemented on the buccal surface of the crowns. For the mechanical tests of compressive and diametral tensile strength and shear bond strength a universal testing machine was used with a crosshead speed of 1,0 mm/min and for the Vickers microhardness analysis tests a Microdurometer was used with 200 g of load during 15 seconds. The results were submitted to statistical analysis through ANOVA complemented by Tukey's test at a significance level of 5%. RESULTS: The results shown that the Multi-Cure Glass Ionomer presented higher diametral tensile strength (p < 0.01) and compressive strength greater than conventional GICs (p = 0.08). Moreover, Ketac Cem showed significant less microhardness (p < 0.01). CONCLUSION: The resin-modified glass ionomer cement showed high mechanical properties, compared to the conventional glass ionomer cements, which had few differences between them.

scholarly journals Preliminary Study on Mechanical Properties of 3D Printed Multimaterials ABS/PC Parts: Effect of Printing Parameters

2021 ◽  
Vol 32 (2) ◽  
pp. 87-104
Author(s):  
Pui-Voon Yap ◽  
Ming-Yeng Chan ◽  
Seong-Chun Koay
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Flexural Modulus ◽  
Nozzle Diameter ◽  
Fused Deposition ◽  
Printing Parameters ◽  
Printing Speed

This research work highlights the mechanical properties of multi-material by fused deposition modelling (FDM). The specimens for tensile and flexural test have been printed using polycarbonate (PC) material at different combinations of printing parameters. The effects of varied printing speed, infill density and nozzle diameter on the mechanical properties of specimens have been investigated. Multi-material specimens were fabricated with acrylonitrile butadiene styrene (ABS) as the base material and PC as the reinforced material at the optimum printing parameter combination. The specimens were then subjected to mechanical testing to observe their tensile strength, Young’s modulus, percentage elongation, flexural strength and flexural modulus. The outcome of replacing half of ABS with PC to create a multi-material part has been examined. As demonstrated by the results, the optimum combination of printing parameters is 60 mm/s printing speed, 15% infill density and 0.8 mm nozzle diameter. The combination of ABS and PC materials as reinforcing material has improved the tensile strength (by 38.46%), Young’s modulus (by 23.40%), flexural strength (by 23.90%) and flexural modulus (by 37.33%) while reducing the ductility by 14.31% as compared to pure ABS. The results have been supported by data and graphs of the analysed specimens.

Study of Concretes Reinforced by Plastic Fibers Based on Local Materials

2019 ◽  
Vol 42 ◽  
pp. 100-108 ◽  
Author(s):  
Adda Hadj Mostefa ◽  
Merdaci Slimane
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Bond Strength ◽  
Environmental Problem ◽  
Splitting Tensile Strength ◽  
Waste Plastic ◽  
Single Use ◽  
Local Materials

This work is carried out to investigate the performance of concrete reinforced with plastic fibers obtained locally (bottle waste as fiber). Bottle waste plastic was chosen because it is being thrown after single use and cause environmental problem. One way to recycle wasted bottles plastic is grinded into irregular fiber. Then, it was incorporate with the concrete and tests the performance of the concrete. The study was conducted using cylindrical and rectangular (cube) mold of concrete to investigate the performance of the concrete in term of mechanical properties. In this research, the mechanical properties that were measured are compressive strength, splitting tensile strength and flexural strength. The results revealed that the presence of plastic fiber in concrete will increase the concrete performance, as well as the concrete bond strength is improved and the cracks in the concrete decrease the use of fibers and reduce plastic waste.

Study on Integrated Properties of PP Composites Filled with Rice Husks Powder

2011 ◽  
Vol 217-218 ◽  
pp. 347-352 ◽  
Author(s):  
Chun Xia He ◽  
Jun Jun Liu ◽  
Pan Fang Xue ◽  
Hong Yan Gu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Water Absorption ◽  
Volume Expansion ◽  
Flexural Modulus ◽  
Expansion Ratio ◽  
Rice Husks ◽  
Elongation Ratio ◽  
Pp Composites

The influence of the rice husks powder (RHP) content and its particle size distribution on the composite’s tensile strength, fracturing elongation ratio, flexural strength and flexural elastic modulus has been investigated. Respective water absorption and thermal properties of PP composites incorporated with different proportion of RHP have also been analyzed. The microstructure of fractured surfaces was further observed in scanning electron microscopy (SEM). The results showed that the composites with RHP of 245 μm have higher mechanical properties. The tensile strength and fracturing elongation ratio decrease with the increase of RHP content, and reach peak values in 30% RHP content. Water absorption and volume expansion ratio of the composite increase with the increasing of RHP content. Flexural strength and flexural modulus decrease after water absorption. When PHR content is low, the RHP particles are well distributed and the interface of RHP and PP is smooth. When PHR content is higher, the RHP particles tend to agglomerate, leading to poorer interface and lower mechanical properties, the composite failed with brittle fracture.

scholarly journals Comparison of Mechanical Properties of Biaxial and Triaxial Fabric and Composites Reinforced by Them

2019 ◽  
Vol 27 (1(133)) ◽  
pp. 37-44
Author(s):  
Marcin Barburski ◽  
Mariusz Urbaniak ◽  
Sanjeeb Kumar Samal
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Resin Matrix ◽  
Reinforced Composites ◽  
Reinforced Composite ◽  
Aramid Fabrics ◽  
Properties Of Composites

In this article, the mechanical properties of biaxial and triaxial woven aramid fabric and respective reinforced composites were investigated. Both fabrics had the same mass/m2. The first part of the experimental investigation was focused on the mechanical properties of different non-laminated aramid fabrics (biaxial and triaxial). The second part was concerned with the mechanical properties of composites made of a different combination of layers of fabric reinforced with an epoxy resin matrix in the order of biaxial+biaxial, trixial+triaxial and biaxial+triaxial. The composites were tested for tensile strength, flexural strength, strain and Young’s and flexural modulus. It can be seen from the results that the density and direction of the yarns are the most important parameters for determination of the strength of the fabric reinforced composite. The biaxial composite clearly showed better tensile strength, while the bi-tri axial order showed good flexural strength compared to the other composite combinations. These fabric reinforced composites have suitable applications in the areas of medical, protection and in the automotive industries.

Influence of Ketones on Selected Mechanical Properties of Resin Composites

1992 ◽  
Vol 71 (11) ◽  
pp. 1847-1850 ◽  
Author(s):  
A. Peutzfeldt ◽  
E. Asmussen
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Cross Linking ◽  
Resin Composites ◽  
Light Curing ◽  
Resistance To Wear ◽  
Modulus Of Resilience ◽  
Diametral Tensile Strength

The present study investigated a concept for additional crosslinking of dental polymers, by which resistance to wear of resin composites might be increased. Bifunctional ketones were added to monomer mixtures, which were then made light-curing and loaded with filler. The monomer mixtures were varied with respect to type and ratio of monomer and ketone. For measurement of possible effects of the cross-linking agents added, four mechanical properties of the experimental resin composites were determined. Addition of the bifunctional ketone diacetyl resulted in the following increases in mechanical properties: diametral tensile strength, 11%; flexural strength, 29%; modulus of elasticity, 19%; and modulus of resilience, 50%.

Effect of Polyethylene Glycol (PEG) on Molten Plasticized Cellulose Acetate (CA)

2013 ◽  
Vol 830 ◽  
pp. 172-175
Author(s):  
Cheng Zhi Chuai ◽  
Zhi Zhang
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
Polyethylene Glycol ◽  
Flexural Strength ◽  
Cellulose Acetate ◽  
Flexural Modulus ◽  
Degree Of Polymerization ◽  
Maximum Elongation ◽  
Elongation At Break

Ethylene glycol (EG) and polyethylene glycol (PEG) were added as plasticizers to improve the processing performance of cellulose acetate (CA). The CA with 30% plasticizers were melted by HAAKE at 200 °C. The effects of EG and PEG (degree of polymerization in 200-800) on rheological properties and mechanical properties of CA were investigated. The results show that the plasticizing time, equilibrium torque and melt viscosity of the plasticizing system increase with the increase of PEG molecular weight, while the processing performance decreased. The tensile strength of the system decrease as the PEG molecular weight increased. The plasticizing system which contents 30% PEG-200(degree of polymerization is 200) shows the maximum elongation at break. The minimum values appeared in both flexural strength and flexural modulus in the CA/PEG-200 system.

scholarly journals A Comparative Study of the Mechanical Properties of Selected Dental Composites with a Dual-Curing System with Light-Curing Composites

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1255
Author(s):  
Monika Domarecka ◽  
Agata Szczesio-Wlodarczyk ◽  
Michał Krasowski ◽  
Magdalena Fronczek ◽  
Tomasz Gozdek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Comparative Study ◽  
Wide Spectrum ◽  
Shrinkage Stress ◽  
Three Point Bending ◽  
Light Curing ◽  
Dual Curing ◽  
Diametral Tensile Strength

Dual-curing composites have a wide spectrum of use in practice (rebuilding, reconstruction, and luting). The characterization of this type of material and comparative study of selected mechanical properties with light-cured materials were carried out for this paper. In this study, we used six materials with a dual-cure system—Bulk EZ, Fill-Up!, StarFill 2B, Rebilda DC, MultiCore Flow, Activa Bioactive-Restorative—and three light-cured materials—Filtek Bulk Fill Posterior, Charisma Classic, and G-aenial Universal Flo. The materials were conditioned for 24 h in water at 37 °C before testing. Selected material properties were determined: three-point bending flexural strength, diametral tensile strength, hardness, microhardness, and shrinkage stress. The highest three-point bending flexural strength (TPB) was 137.0 MPa (G-aenial Universal Flo), while the lowest amounted to 86.5 MPa (Activa Bioactive). The diametral tensile strength (DTS) values were in a range from 39.2 MPa (Rebilda DC) to 54.1 MPa (Charisma Classic). The lowest hardness (HV) value of 26 was obtained by the Activa Bioactive material, while the highest values were recorded for Filtek Bulk Fill Posterior and Charisma Classic-53. The shrinkage stress of the tested materials ranged from 6.3 MPa (Charisma Classic) to 13.2 MPa (G-aenial Universal Flo). Dual-curing composites were found to have similar properties to light-cured composites.

scholarly journals Parameter optimization via the Taguchi method to improve the mechanical properties of bamboo particle reinforced polylactic acid composites

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1914-1939
Author(s):  
R. Nurul Fazita ◽  
Nurnadia Johary ◽  
H. P. S. Abdul Khalil ◽  
Najieha Norazli ◽  
A. Azniwati ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Optimal Parameter ◽  
Flexural Modulus ◽  
Dominant Factor ◽  
Poly Lactic Acid ◽  
Particle Loading ◽  
Impact Properties ◽  
Die Temperature

Reinforcement with natural fibres is a common method to improve impact properties of poly(lactic acid) (PLA). In this study, composites made from PLA and bamboo particles were melt-compounded in a twin-screw extruder and formed by compression moulding. Tensile, flexural, and impact tests were conducted. Particle size (A), particle loading (B), screw speed (C), and die temperature (D) were varied at three levels. Tensile strength and modulus, flexural strength and modulus, and impact strength were the response variables. The experiment design was based on Taguchi’s (L9) orthogonal array. Through variance analysis, the particle loading was found to be the dominant factor influencing the mechanical properties, followed by die temperature. The optimum parameters were validated with a confirmation test. The results showed a noticeable improvement of impact properties compared to neat PLA by 55%, without compromising tensile and flexural properties. Flexural strength, flexural modulus, and tensile modulus of the composites were greater than that of pure PLA. However, only tensile strength was reduced by about 28% compared to pure PLA. Importantly, the DOE method with maximizing the desirability properties was found to be an effective systematic approach to identify an optimal parameter setting of the extrusion moulding process.

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