A Paradigm Shift for Torsional Stiffness of Nickel-Titanium Rotary Instruments: A Finite Element Analysis
| Autor: | Alessio Zanza, Dario Di Nardo, Gianluca Gambarini, Luca Testarelli, Marco Seracchiani, Rodolfo Reda |
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| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
finite element analysis nickel-titanium endodontic instruments polar moment of inertia torsional failure dental alloys equipment design materials testing root canal preparation stress mechanical torsion mechanical nickel titanium Torsion Mechanical Square (algebra) stress 03 medical and health sciences 0302 clinical medicine von Mises yield criterion mechanical Rectangle General Dentistry Physics business.industry Inner core torsion 030206 dentistry Structural engineering Radius Moment of inertia Finite element method 030104 developmental biology Fracture (geology) Stress Mechanical business |
| Zdroj: | Journal of Endodontics. 47:1149-1156 |
| ISSN: | 0099-2399 |
| Popis: | Introduction The aim of this study was to investigate the influence of mass and the polar moment of inertia on the torsional behavior of nickel-titanium rotary instruments to understand which parameter of cross-sectional design had a key role in terms of torsional resistance. Methods Four different instrument models were designed and meshed using computer-aided engineering software (SolidWorks; Dassault Systems, Waltham, MA). Instrument models shared the same characteristics, except for cross-sectional design; triangle, rectangle, square, and hollow square geometry was selected. Finite element analysis was performed simulating a static torsional test using the FEEPlus internal solver (Solid Works). Von Mises stress and torsional load at fracture were calculated by the software. Linear regression analysis was performed to investigate the relationship of the polar moment of inertia, cross-sectional area, inner core radius, and mass per volume on the torsional resistance of nickel-titanium rotary instruments. Results The polar moment of inertia positively affected the maximum torsional load with the highest level of correlation (R2 = 0.917). It could be stated that the higher the polar moment of inertia is, the more maximum torsional load at fracture is present. Mass and cross-sectional area had a lower level of correlation compared with the polar moment of inertia (R2 = 0.5533). According to this, 2 instruments with the same mass/mm and/or cross-sectional area could have different torsional resistance. Conclusions The polar moment of inertia can be considered as the most important cross-sectional factor in determining the torsional resistance of rotary instruments over metal mass and cross-sectional area. |
| Databáze: | OpenAIRE |
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