scholarly journals Analog and digital modeling of sound and impaired periodontal supporting tissues during mechanical testing

2021 ◽  
Vol 15 (2) ◽  
pp. 84-97
Author(s):  
Veronika T. Szabó ◽  
Balázs Szabó ◽  
Tamás Tarjányi ◽  
Eszter Szőke-Trenyik ◽  
Balázs P. Szabó ◽  
...  

Periodontitis is one of the most common conditions affecting oral health among adults, posing a great challenge for both patients and also for dentists aiming to treat this disease. In severe stages such deterioration of the supporting tissues, namely the periodontal ligaments and the bone, can occur, which will affect the biomechanical behavior and therefore the longevity and survival of the affected teeth. In order to be able to plan both periodontal and subsequent restorative treatment properly, valid modelling of the current clinical situation is advised. The aim of the present article is to comprehensively discuss possible analog and digital modeling methods of periodontally affected teeth and the periodontal structures surrounding them. Modelling possibilities can serve later as the basis of mechanical load, digital finite element studies, and also aid clinical treatment planning.

2020 ◽  
Vol 57 (1) ◽  
pp. 272-277
Author(s):  
Adina Oana Armencia ◽  
Loredana Liliana Hurjui ◽  
Cristina Claudia Tarniceriu ◽  
Iulia Saveanu ◽  
Carina Balcos

Simulating the biomechanical behavior of a reconstruction using the finite element analysis method is a modern method necessary before the practical stage of a research, thus enabling the precise shaping of certain trajectories in the approach of certain directions of practical applicability, as well as obtaining final results with relevant data (results coupled with experimental models that reiterate the clinical situation that will be later analyzed).


2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Amira Galal Ismail ◽  
Mohamed Hussein Abdelfattah Zaazou ◽  
Manar Galal ◽  
Nada Omar Mostafa Kamel ◽  
Mohamed Abdulla Nassar

Abstract Background The objective of this study was to assess the bending and torsional properties of two nickel-titanium endodontic files with equivalent sizes and various designs and alloys using finite element analysis, ProTaper Next®X2 (PTN) size 25 with 0.06 taper and WaveOne Gold® (WOG) primary size 25 with 0.07 taper. Methodology Two-dimensional models of the two files PTN and WOG were created using computer tomography scanning and stereomicroscope to produce a three-dimensional digital model. Instrument behavior under bending or torsional conditions was numerically analyzed in SolidWorks software package. Result ProTaper Next® revealed higher flexibility than WaveOne Gold® when exposed to cantilever bending but showed higher stress accumulation than WOG. In terms of torsional resistance, PTN also revealed higher torsional resistance than WOG. Conclusion The geometry of the instrument, thermomechanical treatment of the alloy, and its composition affect the mechanical behavior (bending and torsion) of nickel titanium rotary files. Hence, being aware of these behavioral differences, each clinician will be able to use the adequate file according to the clinical situation in addition to the manufacturer’s instructions.


2012 ◽  
Vol 83 (10) ◽  
pp. 972-980 ◽  
Author(s):  
Srecko Nesic ◽  
Klaus Unruh ◽  
Wilhelm Michels ◽  
Ulrich Krupp

2021 ◽  
Vol 903 ◽  
pp. 79-89
Author(s):  
R. Sundara Rao ◽  
K. Hemachandra Reddy ◽  
Ch.R. Vikram Kumar

In an internal combustion engine poppet valve is the crucial component which often opens and closes, thereby regulating gas flow in an engine cylinder. During engine operation, the valve is exposed to high temperature gases (thermal load) along with spring and cam loads (mechanical load). Due to high temperatures and fatigue loads, the valves are subjected to metallurgical changes and leads to failure. In order to resist these extreme conditions of high temperature and mechanical loads, the engine valve should possess special properties such as high surface hardness, a good amount of thermal conductivity, and fatigue strength. In this work, the reasons for the failure of two wheeler engine valve were evaluated and found that failure takes place due to change in the chemical composition mainly due to thermal diffusion at the interfaces. Thermal barrier coatings on the valve surface arrest the temperature load and increase its life. In this work, the performance of various titanium based composite coatings, i.e., TiN, TiC, TiC-Al2O3, TiCN, TiAlN, TiN- Al2O3, DLC, and uncoated valves of two wheeler engine was simulated using Finite Element Analysis. The simulation results indicated that coated valves have less thermal and fatigue loading and have more life than the uncoated valve. The Finite element simulation results of both coated and uncoated valves are presented and analyzed in this paper.


2019 ◽  
Vol 17 (07) ◽  
pp. 1950029 ◽  
Author(s):  
Lihai Ren ◽  
Dangdang Wang ◽  
Chengyue Jiang ◽  
Yuanzhi Hu

The biofidelity is an essential requirement of the application of human head finite element (FE) models to investigate head injuries under mechanical loadings. However, the influence of the foramen magnum boundary condition (FMBC) on intracranial dynamic responses under head impacts has yet to be fully identified until now. This study aimed to investigate the effect of different modeling methods of the FMBC on intracranial dynamic responses induced by forehead impact, especially the axonal injury associated dynamic responses. The total human model for safety (THUMS) was applied in this study. Two FE models with different FMBC modeling methods were developed from the THUMS model. Then, three forehead impact FE models were established respectively, including the original THUMS model. Further FE simulations were conducted to investigate the influence of FMBC modeling methods on intracranial dynamic responses. Though, difference between the intracranial dynamic responses (relative skull-brain motion and strain responses) at areas far from the foramen magnum were slightly, the corresponding difference at the brain stem area were distinctly. Meanwhile, the predicted axonal injury risk of the brain stem white matter was varying among each other. Different modeling methods of FMBC could result in different intracranial dynamic responses of the brain stem, and affect the axonal injury prediction. Therefore, the modeling of the FMBC should be further evaluated for the study of brain stem injury using human head FE models.


2019 ◽  
Vol 11 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Benedict Jain A.R. Tony ◽  
Masilamany S. Alphin

SummaryStudy aim: Interactions between the fingers and a handle can be analyzed using a finite element finger model. Hence, the biomechanical response of a hybrid human finger model during contact with varying diameter cylindrical handles was investigated numerically in the present study using ABAQUS/CAE.Materials and methods: The finite element index finger model consists of three segments: the proximal, middle, and distal phalanges. The finger model comprises skin, bone, subcutaneous tissue and nail. The skin and subcutaneous tissues were assumed to be non-linearly elastic and linearly visco-elastic. The FE model was applied to predict the contact interaction between the fingers and a handle with 10 N, 20 N, 40 N and 50 N grip forces for four different diameter handles (30 mm, 40 mm, 44mm and 50 mm). The model predictions projected the biomechanical response of the finger during the static gripping analysis with 200 incremental steps.Results: The simulation results showed that the increase in contact area reduced the maximal compressive stress/strain and also the contact pressure on finger skin. It was hypothesized in this study that the diameter of the handle influences the stress/strain and contact pressure within the soft tissue during the contact interactions.Conclusions: The present study may be useful to study the behavior of the finger model under the static gripping of hand-held power tools.


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