scholarly journals A New Device to Test the Bending Resistance of Mechanical Endodontic Instruments

2020 ◽  
Vol 10 (20) ◽  
pp. 7215
Author(s):  
Gabriele Miccoli ◽  
Andrea Cicconetti ◽  
Gianluca Gambarini ◽  
Andrea Del Giudice ◽  
Federico Ripanti ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Nickel Titanium ◽  
Testing Device ◽  
New Device ◽  
Cutting Surface ◽  
Bending Resistance ◽  
Bending Behavior ◽  
Single Instrument ◽  
Rotary Instrument ◽  
New Machine

The aims of the present study were to propose a new machine for testing the bending behavior of an instrument at multiple specific points along the cutting surface and to compare the influence of proprietary heat treatment on the bending ability of EdgeTaper (ET), Protaper Universal (PTU), EdgeTaper Platinum (ETP), and Protaper Gold (PTG). A total of 320 instruments were examined in the present study: 80 ET, 80 PTU, 80 ETP, and 80 PTG. The bending ability of all instruments was tested at a 45° angle and on three different portions of the instrument at 3, 6, and 9 mm from the tip using a customized device. Statistical analysis showed significant differences among each single instrument of the series and between ET and PTU as well as ETP and PTG. The bending behavior of a nickel–titanium rotary instrument is its ability to bend without any plastic deformation. This feature, according to the results of the present study, is variable along the cutting surface; therefore, it should be evaluated. Due to the present testing device, it would be possible to obtain reliable and trustworthy information about an instrument’s bending ability.

scholarly journals Influence of Different Heat Treatments on Torsional and Cyclic Fatigue Resistance of Nickel–Titanium Rotary Files: A Comparative Study

2020 ◽  
Vol 10 (16) ◽  
pp. 5604 ◽  
Author(s):  
Gianluca Gambarini ◽  
Andrea Cicconetti ◽  
Dario Di Nardo ◽  
Gabriele Miccoli ◽  
Alessio Zanza ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Sem Analysis ◽  
Nickel Titanium ◽  
Torsional Resistance ◽  
Heat Treated ◽  
Torsional Test ◽  
Time To Fracture ◽  
Flexural Resistance

Protaper Universal (PTU), Protaper Gold (PTG) (Maillefer, Ballaigues, CH), EdgeTaper (ET), and EdgeTaper Platinum (ETP) (Albuquerque, NM, USA) were tested for both torsional and flexural resistance. The aim of the present study was to evaluate the influence of proprietary heat treatment on the metallurgical properties of the aforementioned instruments. Four groups of 30 different instruments (size 20.07) were tested, then divided into two subgroups of 15 instruments—one for the cyclic fatigue test in a curved canal (90°—2 mm radius) at 300 rpm and 2.5 Ncm. The time to fracture (TtF) and fragment length (FL) were recorded. The other subgroup was subjected to the torsional test (300 rpm, 5.5 Ncm). The torque to fracture and TtF were recorded. All the instruments underwent a SEM analysis. The heat-treated instruments showed a significantly higher fatigue resistance than the non-heat-treated instruments (p < 0.05). No significant differences were found in the torsional resistance between the ET and PTU, and the ETP and PTG. However, when comparing all the groups, the heat-treated instruments showed less torsional resistance. The improvement from heat treatment was mainly found in the cyclic fatigue resistance.

scholarly journals Dyeing of Polyester with Reactive Dyestuffs Using Nano-Chitosan

2018 ◽  
Vol 13 (2) ◽  
pp. 155892501801300
Author(s):  
Neda Najafzadeh ◽  
Sima Habibi ◽  
Mohammadreza A. Ghasri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Morphology ◽  
Reactive Dyes ◽  
Color Difference ◽  
Polyester Fabric ◽  
Surface Chemical ◽  
Bending Resistance ◽  
Bending Behavior ◽  
Scanning Electron

The main objective of this work is to investigate the effect of nano-chitosan on the dyeing of polyester fabric with reactive dyes. Polyester fabric was treated with alkali and coated with nano-chitosan. Afterwards all samples were dyed with reactive dyes. The water absorption and bending resistance of pristine polyester, alkaline and chitosan-treated polyester were measured. In order to investigate surface chemical bonding, FTIR/ATR was employed. Surface morphology of fabrics was observed using scanning electron microscopy (SEM). Wettability and bending behavior of the treated polyester increased compared to the untreated one. The color difference between the dyed blank and chitosan-treated samples was estimated using a spectrophotometer. The data obtained shows it is possible to use reactive dyes to dye polyester fabrics finished with nano-chitosan and the resulting fabrics will exhibit acceptable washing and rubbing fastness.

Fatigue Resistance of a 3-dimensional Conforming Nickel-Titanium Rotary Instrument in Double Curvatures

2016 ◽  
Vol 42 (6) ◽  
pp. 961-964 ◽  
Author(s):  
Ya Shen ◽  
Ahmed Hieawy ◽  
Xiangya Huang ◽  
Zhe-jun Wang ◽  
Hazuki Maezono ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Nickel Titanium ◽  
3 Dimensional ◽  
Rotary Instrument

Influence of Heat Treatment of Nickel-Titanium Rotary Endodontic Instruments on Apical Preparation: A Micro–Computed Tomographic Study

2015 ◽  
Vol 41 (12) ◽  
pp. 2031-2035 ◽  
Author(s):  
Bernardo Corrêa de Almeida ◽  
Fabíola Ormiga ◽  
Marcos César Pimenta de Araújo ◽  
Ricardo Tadeu Lopes ◽  
Inayá Corrêa Barbosa Lima ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Nickel Titanium ◽  
Computed Tomographic

scholarly journals Research of a Novel Ag Temperature Sensor Based on Fabric Substrate Fabricated by Magnetron Sputtering

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6014
Author(s):  
Zong-Yao Yan ◽  
Jian-Yong Liu ◽  
Jia-Rong Niu
Keyword(s):  
Heat Treatment ◽  
Magnetron Sputtering ◽  
Temperature Sensor ◽  
Polyester Fabric ◽  
Heat Treatment Condition ◽  
Good Reliability ◽  
Sputtering Power ◽  
Ag Particles ◽  
Bending Resistance ◽  
Wearable Products

TPU-coated polyester fabric was used as the substrate of a flexible temperature sensor and Ag nanoparticles were deposited on its surface as the temperature sensing layer by the magnetron sputtering method. The effects of sputtering powers and heat treatment on properties of the sensing layers, such as the temperature coefficient of resistance (TCR), linearity, hysteresis, drift, reliability, and bending resistance, were mainly studied. The results showed that the TCR (0.00234 °C−1) was the highest when sputtering power was 90 W and sputtering pressure was 0.8 Pa. The crystallinity of Ag particles would improve, as the TCR was improved to 0.00262 °C−1 under heat treatment condition at 160°. The Ag layer obtained excellent linearity, lower hysteresis and drift value, as well as good reliability and bending resistance when the sputtering power was 90 W. The flexible temperature sensor based on the coated polyester fabric improved the softness and comfortableness of sensor, which can be further applied in intelligent wearable products.

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