scholarly journals Finite Element Study on Continuous Rotating versus Reciprocating Nickel-Titanium Instruments

2016 ◽  
Vol 27 (4) ◽  
pp. 436-441 ◽  
Author(s):  
Mohamed I. El-Anwar ◽  
Salah A. Yousief ◽  
Engy M. Kataia ◽  
Tarek M. Abd El-Wahab
Keyword(s):  
Finite Element ◽  
Low Cost ◽  
Nickel Titanium ◽  
Finite Element Models ◽  
Element Analysis ◽  
Cross Sectional ◽  
Design And Manufacturing ◽  
Cad Cam ◽  
Strain Stress ◽  
Sectional Shape

Abstract In the present study, GTX and ProTaper as continuous rotating endodontic files were numerically compared with WaveOne reciprocating file using finite element analysis, aiming at having a low cost, accurate/trustworthy comparison as well as finding out the effect of instrument design and manufacturing material on its lifespan. Two 3D finite element models were especially prepared for this comparison. Commercial engineering CAD/CAM package was used to model full detailed flute geometries of the instruments. Multi-linear materials were defined in analysis by using real strain-stress data of NiTi and M-Wire. Non-linear static analysis was performed to simulate the instrument inside root canal at a 45° angle in the apical portion and subjected to 0.3 N.cm torsion. The three simulations in this study showed that M-Wire is slightly more resistant to failure than conventional NiTi. On the other hand, both materials are fairly similar in case of severe locking conditions. For the same instrument geometry, M-Wire instruments may have longer lifespan than the conventional NiTi ones. In case of severe locking conditions both materials will fail similarly. Larger cross sectional area (function of instrument taper) resisted better to failure than the smaller ones, while the cross sectional shape and its cutting angles could affect instrument cutting efficiency.

scholarly journals Influence of nickel-titanium rotary systems with varying cross-sectional, pitch, and rotational speed on deflection and cyclic fatigue: a finite element analysis study

2021 ◽  
Vol 41 ◽  
pp. 05005
Author(s):  
Wignyo Hadriyanto ◽  
Lukita Wardani ◽  
Christina Nugrohowati ◽  
Ananto Alhasyimi ◽  
Rachmat Sriwijaya ◽  
...  
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Rotational Speed ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Element Analysis ◽  
Cross Sectional ◽  
Rotary Instruments ◽  
Section Design ◽  
Sectional Shape

The effectiveness of endodontic file preparation depends, among others, on the material, geometric shape, and the drive system. This study aimed to analyze the effect of cross-sectional, pitch, and rotational speed on cyclic fatigue and deflection of NiTi files using finite element analyses. A total of 18 NiTi endodontic rotary instruments ProTaper Gold F2 #25.08 and Hyflex CM #25.04 (n=9) modeling were designed using Autodesk software. Subjects were divided into two groups, the design group of square and convex triangles. Static simulation was then carried out to each group with force on the instrument’s tip by 1N, 2N, and 3N. The file’s cycling fatigue was analyzed at rotating speeds of 200 rpm, 300 rpm, and 400. The data were analyzed by using the three-way Analysis of variance (ANOVA) test followed by LSD (p< 0.05). The results showed the cross-sectional shape and force effect on the deflection value and cyclic fatigue received by the endodontic files (p< 0.05). The convex triangle design presented the lowest cyclic fatigue than square. The convex triangular cross-section design showed a higher deflection value than the square cross-section design.

scholarly journals Influence of Thermomechanical Treatment on the Mechanical Behavior of Protaper Gold versus Protaper Universal (A Finite Element Study)

2019 ◽  
Vol 7 (13) ◽  
pp. 2157-2161 ◽  
Author(s):  
Manar Galal ◽  
Amira Galal Ismail ◽  
Nada Omar ◽  
Mohamed Zaazou ◽  
Mohamed Abdallah Nassar
Keyword(s):  
Finite Element ◽  
Thermomechanical Treatment ◽  
Mechanical Response ◽  
3D Models ◽  
Nickel Titanium ◽  
Element Analysis ◽  
Torsional Resistance ◽  
Cad Cam ◽  
Flexural Resistance ◽  
Cam Software

AIM: To compare and evaluate the influence of thermomechanical treatment of Protaper Gold file versus Protaper Universal file during testing of bending and torsion using finite-element analysis. METHODS: Two nickel-titanium NiTi rotary files (ProTaper Gold and ProTaper Universal) were used in this study. The files were imaged using stereomicroscope to produce 3D models. The behaviour of the instrument during bending and torsion was numerically analysed in CAD/CAM software package. RESULTS: Under bending, ProTaper, Gold showed higher flexibility and flexural resistance than ProTaper Universal. The highest stress was related at the cutting edge of both files. While during testing of torsion, the maximum amount of stresses was related to the base of the flutes in both files. ProTaper Gold showed higher torsional resistance than the ProTaper Universal file. CONCLUSION: Thermomechanical treatment improved the mechanical response (bending and torsional resistance) of NiTi files.

scholarly journals Influence of Number of Implants and Attachment Type on Stress Distribution in Mandibular Implant-Retained Overdentures: Finite Element Analysis

2017 ◽  
Vol 5 (2) ◽  
pp. 244-249 ◽  
Author(s):  
Mohamed I. El-Anwar ◽  
Eman A. El-Taftazany ◽  
Hamdy A. Hamed ◽  
Mohamed A. Abd ElHay
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Models ◽  
Oblique Angle ◽  
Element Analysis ◽  
3D Finite Element ◽  
Cad Cam ◽  
The Right ◽  
Molar Region

AIM: This study aimed to compare the stresses generated by using two or four root form dental implants supporting mandibular overdentures that were retained with ball and locator attachments.METHODS: Under ANSYS environment, four 3D finite element models were prepared. These models simulated complete overdentures supported by two or four implants with either ball or locator attachments as a connection mechanism. The models’ components were created by CAD/CAM package then were imported to ANSYS. Load of 100 N was applied at the right premolar/molar region vertically and at an oblique angle of 110° from lingual direction.RESULTS: Within the conditions of this research, in all cases, it was found that cortical and cancellous bone regions were the least to be stressed. Also, the ball attachment produced higher stresses.CONCLUSION: Caps deformation and stresses are negligible in cases of using locator attachment in comparison to ball attachments. This may indicate longer lifetime and less repair/maintenance operations in implant overdentures retained by locator attachments. Although the study revealed that bone was insensitive to a number of implants or attachment type, it may be recommended to use two implants in the canine region than using four, where the locator attachments were found to be better.

scholarly journals A Study on the Influence of the Cross-Sectional Shape of the Metal-Inserted Retainer Ring and the Pressure Distribution from the Multi-Zone Carrier Head to Increase the Wafer Yield

2020 ◽  
Vol 10 (23) ◽  
pp. 8362
Author(s):  
Joon-Yeon Park ◽  
Je-Heon Han ◽  
Changwon Kim
Keyword(s):  
Finite Element ◽  
Pressure Distribution ◽  
Model Simulation ◽  
Removal Rate ◽  
Element Model ◽  
Analysis Model ◽  
Element Analysis ◽  
Cross Sectional ◽  
The Cross ◽  
Sectional Shape

In this paper, for the purpose of increasing the wafer yield by controlling the non-uniformity of the material removal rate during the chemical mechanical polishing process, the influence of the cross-sectional shape of the metal-inserted retainer ring and the pressure distribution on the wafer and the retainer ring generated from the multi-zone carrier head are investigated. First, in order to verify the finite element analysis model, it is correlated using the test data. By using a validated finite element model, simulation studies involving several parameters are performed to reduce the irregularity in the wafer: (1) tapered bottom of the retainer ring, (2) machining round corners at the bottom of the retainer ring, (3) the changes in pressure applied to the wafer, (4) the changes in pressure applied to the retainer ring.

Impact of Helix and Taper on Structural Characteristics of a Nickel-Titanium Endodontic Instrument Through Finite Element Analysis

2006 ◽  
Author(s):  
Rui He ◽  
Charles J. Goodis ◽  
Jun Ni
Keyword(s):  
Finite Element ◽  
Mechanical Performance ◽  
Structural Characteristics ◽  
Sustainable Use ◽  
Nickel Titanium ◽  
Torsional Stiffness ◽  
Finite Element Models ◽  
The Finite Element Method ◽  
Clinical Practices ◽  
Element Analysis

The mechanical behavior of a rotary nickel-titanium endodontic instrument was evaluated through finite element models. Essential geometric features of blank taper and variable pitch were modeled and their impact on the mechanical performance of instruments was investigated. Simulation results showed that better bending flexibility and higher torsional stiffness can both be obtained on an instrument with a large helix configuration. The results also illustrated that the finite element method can be used to compute the critical load or deformation for the instrument which prompts the sustainable use of the instrument in clinical practices.

Static Finite Element Analysis of Container Flooring and Chassis Combinations

2010 ◽  
Vol 160-162 ◽  
pp. 389-394
Author(s):  
Quan Zhong Wang ◽  
Chang Jiang He ◽  
Bin Xu
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Maximum Stress ◽  
New Combination ◽  
Original Structure ◽  
Element Analysis ◽  
Cross Sectional ◽  
Maximum Deformation ◽  
The Difference ◽  
Sectional Shape

We analyzed static finite element of the container flooring and chassis combination structure rolling by a car; then, we analyzed the maximum deformation and corresponding maximum stress of the flooring and chassis combination when chassis crossbeam cross-sectional shape from the U-shaped to the I-shaped and compared with the original structure with the same force, as well as the space between the central crossbeam decreased, we can see that, the appropriate crossbeam space can obviously increase the stiffness of the container and reduce the stress of the structure; at the same time, we analyzed the combinations which with different flooring structures, we can see that the difference deformation between the new combination and the original was small, so we know that the mechanical properties of flooring had little effect to the mechanical properties of the entire combination.

Mathematical Expressions of Helical Thread Geometry and Cross Sectional Areas of Various Shaped Thread Forms and Finite Element Analysis

2013 ◽  
Author(s):  
Kenya Yanase ◽  
Toshimichi Fukuoka
Keyword(s):  
Finite Element ◽  
Axial Stress ◽  
Mathematical Expression ◽  
Bolted Joints ◽  
Finite Element Models ◽  
Element Analysis ◽  
Cross Sectional ◽  
Single Thread ◽  
Mathematical Expressions ◽  
Multiple Thread

Distinctive mechanical behavior of bolted joints is caused by the helical shape of thread geometry. Mathematical expression of the helical thread geometry of a single-thread screw has successfully been derived in the previous study. Using the derived equations, finite element models were constructed by taking account of the effect of the helix, and it is clarified how the stress distributes along the thread root and where the maximum stress occurs. Meanwhile, there are various thread forms other than a single-thread triangular screw. In this study, mathematical expressions of the helical thread geometry and the cross sectional areas of multiple-thread screws, pipe thread, trapezoidal thread and rectangular thread are derived in the same manner as in the case of a single-thread screw. Using the equations so obtained, finite element models with multiple-thread screws are constructed. From the numerical results, it is found that the maximum axial stress occurred in the bolted joints on a double-thread screw is slightly larger than the case of a single-thread screw, although the stress distribution patterns are almost identical in both types of screw geometry.

A Finite Element Analysis of the General Rolling Contact Problem for a Viscoelastic Rubber Cylinder

1988 ◽  
Vol 16 (1) ◽  
pp. 18-43 ◽  
Author(s):  
J. T. Oden ◽  
T. L. Lin ◽  
J. M. Bass
Keyword(s):  
Finite Element ◽  
Variational Principles ◽  
Standing Waves ◽  
Rolling Contact ◽  
Finite Element Models ◽  
Viscoelastic Cylinder ◽  
Element Analysis ◽  
Elastic Rubber ◽  
Frictional Effects ◽  
Rough Foundation

Abstract Mathematical models of finite deformation of a rolling viscoelastic cylinder in contact with a rough foundation are developed in preparation for a general model for rolling tires. Variational principles and finite element models are derived. Numerical results are obtained for a variety of cases, including that of a pure elastic rubber cylinder, a viscoelastic cylinder, the development of standing waves, and frictional effects.

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