scholarly journals Fatigue Design of Dental Implant Assemblies: A Nominal Stress Approach

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 744 ◽  
Author(s):  
Mikel Armentia ◽  
Mikel Abasolo ◽  
Ibai Coria ◽  
Joseba Albizuri
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Experimental Tests ◽  
Design Tool ◽  
Nominal Stress ◽  
Fe Model ◽  
Element Analysis ◽  
Iso 14801

Fatigue is the most common mechanical failure type in dental implants. ISO 14801 standardizes fatigue testing of dental implants, providing the load-life curve which is most useful for comparing the fatigue behavior of different dental implant designs. Based on it, many works were published in the dental implant literature, comparing different materials, component geometries, connection types, surface treatments, etc. These works are useful for clinicians in order to identify the best options available in the market. The present work is intended not for clinicians but for dental implant manufacturers, developing a design tool that combines Finite Element Analysis, fatigue formulation and ISO 14801 experimental tests. For that purpose, 46 experimental tests were performed on BTI INTERNA® IIPSCA4513 implants joined with INPPTU44 abutments by means of INTTUH prosthetic screws under three different tightening torque magnitudes. Then, the load case was reproduced in a FE model from where the nominal stress state in the fatigue critical section was worked out. Finally, Walker criterion was used to represent accurately the effects of mean stress and predict fatigue life of the studied dental implant assembly, which can be extended to most of the products of BTI manufacturer. By means of this tool, dental implant manufacturers will be able to identify the critical design and assembly parameters in terms of fatigue behavior, evaluate their influence in preliminary design stages and consequently design dental implants with significantly better fatigue response which in turn will reduce future clinical incidences.

scholarly journals On the Use of a Simplified Slip Limit Equation to Predict Screw Self-Loosening of Dental Implants Subjected to External Cycling Loading

2020 ◽  
Vol 10 (19) ◽  
pp. 6748
Author(s):  
Mikel Armentia ◽  
Mikel Abasolo ◽  
Ibai Coria ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Stress Test ◽  
Experimental Tests ◽  
Design Stage ◽  
Fe Model ◽  
Preliminary Design ◽  
Structural Failure ◽  
Crestal Bone Loss ◽  
Preliminary Design Stage

Self-loosening of the prosthetic screws is a major mechanical problem affecting roughly 10% of dental implants, according to the literature. This phenomenon may lead to micro-movements that produce crestal bone loss, peri-implantitis, or structural failure of the implant assembly. In this paper, a simple and effective tool to predict self-loosening under masticatory loads is presented. The loads acting on the screw are obtained from a simple finite element (FE) model, and introduced in a mathematical formula that calculates the torque needed to loosen the screw; self-loosening will occur when this torque becomes zero. In this sense, all the parameters involved in self-loosening phenomenon can be easily identified, and their effect quantified. For validating purposes, 90 experimental tests were performed in a direct stress test bench. As a result, a powerful tool with a maximum experimental error of 7.6% is presented, allowing dental implant manufacturers to predict eventual occurrence of self-loosening in their developed dental implant products and take corrective actions at preliminary design stage. Furthermore, the following clinical implications can be directly derived from the methodology: a higher screw preload, that is a higher tightening torque, improves self-loosening response of the dental implant and, similarly, for a given preload force, higher friction coefficient and screw metric, as well as lower pitch and thread angle values, are also found to be beneficial.

scholarly journals Biomechanical Design Application on the Effect of Different Occlusion Conditions on Dental Implants with Different Positions—A Finite Element Analysis

2020 ◽  
Vol 10 (17) ◽  
pp. 5826
Author(s):  
Pei-Ju Lin ◽  
Kuo-Chih Su
Keyword(s):  
Finite Element ◽  
Temporomandibular Joint ◽  
Dental Implants ◽  
Dental Implant ◽  
Reaction Force ◽  
Biomechanical Analysis ◽  
Element Analysis ◽  
Group Function ◽  
Implant System ◽  
The Impact

A dental implant is currently the most commonly used treatment for patients with lost teeth. There is no biomechanical reference available to study the effect of different occlusion conditions on dental implants with different positions. Therefore, the aim of this study was to conduct a biomechanical analysis of the impact of four common occlusion conditions on the different positions of dental implants using the finite element method. We built a finite element model that included the entire mandible and implanted seven dental implant fixtures. We also applied external force to the position of muscles on the mandible of the superficial masseter, deep masseter, medial pterygoid, anterior temporalis, middle temporalis, and posterior temporalis to simulate the four clenching tasks, namely the incisal clench (INC), intercuspal position (ICP), right unilateral molar clench (RMOL), and right group function (RGF). The main indicators measured in this study were the reaction force on the temporomandibular joint (TMJ) and the fixed top end of the abutment in the dental implant system, and the stress on the mandible and dental implant systems. The results of the study showed that under the occlusion conditions of RMOL, the dental implant system (113.99 MPa) and the entire mandible (46.036 MPa) experienced significantly higher stress, and the reaction force on the fixed-top end of the abutment in the dental implant system (261.09 N) were also stronger. Under the occlusion of ICP, there was a greater reaction force (365.8 N) on the temporomandibular joint. In addition, it was found that the reaction force on the posterior region (26.968 N to 261.09 N) was not necessarily greater than that on the anterior region (28.819 N to 70.431 N). This information can help clinicians and dental implant researchers understand the impact of different chewing forces on the dental implant system at different positions after the implantation.

Fatigue Evaluation of a New Two-Piece Dental Implant, Having a Replaceable Titanium Sleeve

2020 ◽  
Author(s):  
Chaushu Liat ◽  
Chaushu Gavriel
Keyword(s):  
Dental Implants ◽  
Fatigue Test ◽  
Dental Implant ◽  
Load Level ◽  
Endosseous Implant ◽  
Fatigue Evaluation ◽  
Iso 14801 ◽  
Dynamic Fatigue

Abstract A new two-piece dental implant, having a replaceable thin titanium sleeve in its 5mm crestal part was designed. The use of a sleeve of near 0.2mm thickness reduces implant diameter by 0.4mm. Narrower diameter implants may increase the likelihood of component fracture in dental implant systems. 14 two-piece dental implants, with 25° abutment angle were subjected to a dynamic fatigue test according to DIN EN ISO 14801. The highest load at which a runout (non-failure) occurred at 5x106 cycles, amounted to 575 N. According to DIN EN ISO 14801, this load level was confirmed with n=3 samples. The Wöhler curve was determined. Accordingly, the runout at 106 cycles can be anticipated as 625N. The new two-piece Implant B™ design using a 0.2 mm sleeve is compatible with the DIN EN ISO 14801 standard for dimensions of 4.2mm diameter and 13mm length. It withstands dynamic fatigue test at least as good as any other standard endosseous implant.

A SIMPLE AND EFFICIENT METHODOLOGY TO IMPROVE DESIGN PROPOSALS OF DENTAL IMPLANTS — A DESIGN CASE STUDY

2015 ◽  
Vol 27 (04) ◽  
pp. 1550037 ◽  
Author(s):  
G. Uzcátegui ◽  
E. Dávila ◽  
M. Cerrolaza
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Geometric Characteristic ◽  
Von Mises Stress ◽  
Implant Design ◽  
Improve Design ◽  
Final Design ◽  
Improved Performance ◽  
Von Mises ◽  
Iso 14801

Objective: To propose a methodology based on virtual simulation to assist in the design proposals of dental implants. Methods: The finite element method (FEM) was used to analyze the biomechanical dental implant system behavior, determining von Mises stress distribution induced by functional loads, varying parameter as load direction and geometric characteristic of the implant (taper, length, abutment angulation, thread pitch and width pitch). A final design was obtained by considering the parameters that showed improved performance. The estimated lifetime of the final design was calculated by reproducing in a virtual way the experimental fatigue test required by the ISO:14801 standards. Results: For all the studied cases, the maximum stresses were obtained in the connecting screw under oblique loads (OLs). The estimated lifetime for this critical part is at least 5 × 106 cycles, which meets the requirement of the ISO:14801. In bone tissue, the largest stresses were concentrated in cortical bone, in the zone surrounding the implant, in good agreement with previous reports. Conclusions: A dental implant design was obtained and validated through a simple and efficient methodology based on the application of numerical methods and computer simulations.

scholarly journals Interfacial crack arrest in sandwich beams subjected to fatigue loading using a novel crack arresting device – Numerical modelling

2017 ◽  
Vol 21 (2) ◽  
pp. 422-438 ◽  
Author(s):  
G Martakos ◽  
JH Andreasen ◽  
C Berggreen ◽  
OT Thomsen
Keyword(s):  
Finite Element ◽  
Sandwich Beam ◽  
Interfacial Crack ◽  
Fatigue Loading ◽  
Element Model ◽  
Crack Arrest ◽  
Design Tool ◽  
Fe Model ◽  
Sandwich Beams ◽  
Element Analysis

A novel crack arresting device is implemented in foam-cored composite sandwich beams and tested using the Sandwich Tear Test (STT) configuration. A finite element model of the setup is developed, and the predictions are correlated with observations and results from a recently conducted experimental fatigue test study. Based on a linear elastic fracture mechanics approach, the developed FE model is utilised to simulate crack propagation and arrest in foam-cored sandwich beam specimens subjected to fatigue loading conditions. The effect of the crack arresters on the fatigue life is analysed, and the predictive results are subsequently compared with the observations from the previously conducted fatigue tests. The FE model predicts the energy release rate and the mode mixity based on the derived crack surface displacements, utilising algorithms for the prediction of accelerated fatigue crack growth as well as the strain field evolution in the vicinity of the crack tip on the surface of the sandwich specimens. It is further shown that the developed finite element analysis methodology can be used to gain a deeper insight onto the physics and behavioural characteristics of the novel peel stopper concept, as well as a design tool that can be used for the implementation of crack arresting devises in engineering applications of sandwich components and structures.

scholarly journals NUMERICAL COMPARISON OF TRANSGINGIVAL AND SUBGINGIVAL DENTAL IMPLANTS IN REGARD TO THEIR STRESS DISTRIBUTIONS

2021 ◽  
Vol 30 ◽  
pp. 81-86
Author(s):  
Luboš Řehounek ◽  
Aleš Jíra ◽  
Gabriela Javorská ◽  
Daniel Bodlák
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Extreme Values ◽  
Mechanical Tests ◽  
Numerical Comparison ◽  
Stress Distributions ◽  
Screw Head ◽  
Alternative Variant ◽  
New Variant ◽  
Iso 14801

Most modern dental implants differentiate in regard to the fixation of the abutment into two main categories - the external or internal hexagon or octagon. We performed mechanical tests according to the ČSN EN ISO 14801 standard on a dental implant variant using the external hex. We found that failure of all implant specimens occured below the screw head. To improve the current geometry, we performed numerical analysis of an alternative variant (internal hex) and compared it with analysis of the current geometry (external hex). It was found that the stress distribution of the variant with internal hex is preferable to the old variant. Although extreme values of shear stress in the corresponding plane of loading are higher, they do not concentrate below the screw head, where the screw itself is thinner and more prone to breaking. Therefore, it seems that the new variant of the dental implant is stronger, which is still to be proven by mechanical tests.

scholarly journals Comparative stability analysis of two types of CpTi and Zr-2.5% Nb implants after maxillofacial surgery

2017 ◽  
Vol 8 (2) ◽  
pp. 49-54
Author(s):  
Adel Pirjamalineisiani ◽  
Mohsen Sarafbidabad
Keyword(s):  
Cortical Bone ◽  
Dental Implants ◽  
Dental Implant ◽  
Maxillofacial Surgery ◽  
Simulation Method ◽  
Drilling Process ◽  
Element Analysis ◽  
Finite Element Analysis Simulation ◽  
Different Types ◽  
Implant Loading

Background. Improving the implantation conditions in order to reduce the failure is always desirable for researchers. The aim of this study was to compare two different types of dental implant materials from biomechnical viewpoint in order to introduce a novel simulation method to select suitable materials for dental implants. Methods. In this research, drilling process was performed in the cortical bone of the mandible by finite element analysis simulation. Then, a 3D model of the produced hole in the drilled site was derived and a dental implant model by ITI design was inserted into the cavity. The space remaining between the implant and cavity was considered as a newly formed cortical bone area. Implant loading was performed on two dental implants with different types of material. The change in the volume of the cortical bone around each implant was considered a criterion for evaluating bone damage. Additionally, the micromotion of dental implant in the mandible after implantation was used for investigating dental implant stability. Results. After implant loading, the volume changes in newly formed cortical bone around Ti and Zr-2.5%Nb dental implants were measured at 0.010809 and 0.010996 mm3 , respectively. Furthermore, micromotion of Ti and Zr-2.5%Nb dental implants were measured at 0.00514 and 0.00538 mm, respectively. Conclusion. This study showed that Ti dental implant creates better conditions than Zr-2.5%Nb dental implant in the maxillofacial region

scholarly journals A Finite Element Analysis of the Fatigue Behavior and Risk of Failure of Immediate Provisional Implants

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 535
Author(s):  
María Prados-Privado ◽  
Carlos Ivorra ◽  
Carlos Martínez-Martínez ◽  
Sergio Alexandre Gehrke ◽  
José Luis Calvo-Guirado ◽  
...  
Keyword(s):  
Finite Element ◽  
Dental Implants ◽  
Fatigue Behavior ◽  
Maximum Load ◽  
Probability Of Failure ◽  
Fracture Load ◽  
Element Analysis ◽  
Compression Load ◽  
Maximum Value ◽  
Number Of Cycles

Background: Temporary dental implants are used to support provisional prostheses. The goal of this study was to obtain the stress–number (S–N) curves of cycles of five temporary dental implants employing finite element methods. Additionally, a probabilistic analysis was carried out to obtain the failure probability of each dental implant. Methods: To obtain these curves, first the maximum value of the fracture load was obtained by simulation of a compression test. Subsequently, the fatigue life was simulated by varying each of the loads from the maximum value to a minimum value (10% of the maximum value), and the minimum number of cycles that it should support was calculated. Results: The fatigue limit of titanium in these implants was around 200 MPa with the maximum number of cycles between 64,976 and 256,830. The maximum compression load was between 100 and 80 N. Regarding the probability of failure, all implants were expected to behave similarly. Conclusions: This study of finite elements provided the values of maximum load supported by each of the implants, and the relationship between the stress in the implant and the number of cycles that it could support with a probability of failure. An international standard on how to perform fatigue studies in temporary dental implants was deemed necessary.

Different Methods for Fatigue Assessment of T Welded Joints Used in Ship Structures

2007 ◽  
Vol 51 (02) ◽  
pp. 150-159 ◽  
Author(s):  
V. Crupi ◽  
E. Guglielmino ◽  
A. Risitano ◽  
D. Taylor
Keyword(s):  
Welded Joints ◽  
Fatigue Behavior ◽  
Experimental Tests ◽  
Ship Structures ◽  
Element Analysis ◽  
Fatigue Assessment ◽  
Endurance Limits ◽  
Thermographic Analysis ◽  
Using Data ◽  
Cycle Endurance

The aim of this work is the prediction of high-cycle fatigue behavior in welded joints, which represent regions of weakness in the ship structures. The traditional methods for fatigue assessment of welded joints have some limitations. Some new methods were recently developed by Taylor: the crack modeling method (CMM) and the theory of critical distances methods (TCD). Experimental tests were carried out to define the high-cycle endurance limits of aluminum T-shaped welded joints. Using data obtained from finite element analysis (FEA), the fatigue strength was evaluated according to the CMM and the TCD. Thermographic analysis was also carried out during the experimental tests to assess the high-cycle endurance limits of the welds by means of the Risitano method (RM). The previous methods were also applied to a specific case, fatigue in T joints containing a drilled hole at different angles, which allowed us to study a typical industrial design problem involving two different features. Good predictions were achieved using all the methods.

Finite Element Analysis of Stress in Dental Bridge with Implant

2020 ◽  
Vol 10 (6) ◽  
pp. 743-748
Author(s):  
Wan-Ting Huang ◽  
Han-Yi Cheng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dental Implants ◽  
Dental Implant ◽  
Computer Tomography ◽  
Effective Means ◽  
Control Group ◽  
Finite Element Models ◽  
Element Analysis

The objective of this research was to investigate dental bridges with and without implants. Threedimensional (3D) mandible models were reconstructed by computer tomography (CT) to simulate biting behaviors. The dental implant is an important factor in dental bridge applications. Several studies have investigated finite element models for dental implants; however, few have examined a model for dental bridge with implant. The results revealed that stress was significantly increased when dental bridge was used with implant. Moreover, the dental bridge with implant group demonstrated a relatively big stress in mandible, which was 4.01% lower compared with that of the control group. Dental bridge would be an effective means of recovering dental performance. However, the present research stated that the implant of dental bridge has a potential to increase abnormal stress, and uniformly distributing stress in the dental bridges.

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