Evaluation of dynamic and static torsional resistances of nickel-titanium rotary instruments
| Autor: | Jung-Hong Ha, Sang Won Kwak, Ibrahim H. Abu-Tahun, Hyeon-Cheol Kim |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Yield (engineering)
Materials science Scanning electron microscope 02 engineering and technology Dynamic resistance Torsional resistance 03 medical and health sciences 0302 clinical medicine Torque Nickel-titanium rotary instrument General Dentistry business.industry Torsional strength 030206 dentistry Structural engineering 021001 nanoscience & nanotechnology lcsh:RK1-715 Fracture Nickel titanium Static rotation lcsh:Dentistry Fracture (geology) Dynamic repetitive load Original Article 0210 nano-technology business |
| Zdroj: | Journal of Dental Sciences, Vol 13, Iss 3, Pp 207-212 (2018) Journal of Dental Sciences |
| ISSN: | 1991-7902 |
| Popis: | Background/purpose: This study evaluated the torsional resistances of nickel-titanium rotary instruments by two methods: i) dynamic resistance: repetitive torsional loading (RTL) and ii) static resistance: single torsional loading (STL) based on the International Organization for Standardization. Materials and methods: In RTL method, a pre-set rotational loading (0.5 N cm) was applied after fixing the 3-mm tip of the file, and this clockwise loading to the pre-set torque and counter-clockwise unloading to original position was repeated at 50 rpm until the file fractured. The number of repetition cycles until fracture was counted. In STL method, the torsional strength was determined by continuous clockwise rotation (2 rpm) until fracture. Results from both methods were compared after testing the torsional resistances of four instrument systems (n = 15): Hyflex CM, HyFlex EDM, V-Taper2, and V-Taper2H. A scanning electron microscope (SEM) was used to examine the topographic features of the fractured surfaces and longitudinal aspects (n = 5) from both methods. Results: The RTL and STL methods had similar results: V-Taper2 had the highest resistance and the Hyflex CM had the lowest (P |
| Databáze: | OpenAIRE |
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