Premium
Study on bending behaviour of nickel–titanium rotary endodontic instruments by analytical and numerical analyses
Author(s) -
Tsao C. C.,
Liou J. U.,
Wen P. H.,
Peng C. C.,
Liu T. S.
Publication year - 2013
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12025
Subject(s) - nickel titanium , finite element method , bending , curvature , nonlinear system , structural engineering , materials science , deformation (meteorology) , stress (linguistics) , mechanics , mechanical engineering , engineering , mathematics , geometry , composite material , physics , shape memory alloy , linguistics , philosophy , quantum mechanics
Aim To develop analytical models and analyse the stress distribution and flexibility of nickel–titanium ( NiTi ) instruments subject to bending forces. Methodology The analytical method was used to analyse the behaviours of NiTi instruments under bending forces. Two NiTi instruments ( R a C e and M ani NRT ) with different cross‐sections and geometries were considered. Analytical results were derived using E uler– B ernoulli nonlinear differential equations that took into account the screw pitch variation of these NiTi instruments. In addition, the nonlinear deformation analysis based on the analytical model and the finite element nonlinear analysis was carried out. Numerical results are obtained by carrying out a finite element method. Results According to analytical results, the maximum curvature of the instrument occurs near the instrument tip. Results of the finite element analysis revealed that the position of maximum von M ises stress was near the instrument tip. Therefore, the proposed analytical model can be used to predict the position of maximum curvature in the instrument where fracture may occur. Finally, results of analytical and numerical models were compatible. Conclusion The proposed analytical model was validated by numerical results in analysing bending deformation of NiTi instruments. The analytical model is useful in the design and analysis of instruments. The proposed theoretical model is effective in studying the flexibility of NiTi instruments. Compared with the finite element method, the analytical model can deal conveniently and effectively with the subject of bending behaviour of rotary NiTi endodontic instruments.