Stress Analysis of Prostheses Retained with Zygomatic Implants on Augmented and Non-Augmented Maxillary Sinus

2020 ◽  
Vol 10 (3) ◽  
pp. 336-340
Author(s):  
Hamiyet Güngör ◽  
Süleyman Kaman ◽  
Ozkan Ozgul ◽  
M. Ercüment Önder ◽  
Fethi Atil ◽  
...  

Zygomatic implants for toothless, atrophic posterior maxilla are effective treatment options and it is known that graft use has a positive effect on the zygomatic implant stability with this treatment option. The aim of this study was to evaluate the stress values and their distribution at zygomatic implant-supported prosthetic infrastructure in augmented and non-augmented models. In this study, the three-dimensional finite element method was used and 2 zygomatic implants (47.5 × 4.0 mm), 2 conventional implants (13 × 3.75 mm) and atrophic maxilla with augmented and non-augmented maxillary sinus with prosthetic infrastructure, were modelled. A vertical load of 150 N was applied onto the maxillary model at 4 different regions (#9, #12, #14 and #15). The von Mises stress, which is produced as a result of loading of zygomatic implants and prosthetic infrastructure has been evaluated in augmented and non-augmented models. The highest von Mises stress value for the prosthetic infrastructure was determined in the non-augmented model as a result of the loading to region #9 (MPa 222,886). Consequently, grafting procedures will increase bone support and reduce stresses in the prosthetic substructure, especially in posterior loads in the maxilla with low bone density.

Scanning ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Xuan Wang ◽  
Tianqi Zhang ◽  
Enli Yang ◽  
Zhiyuan Gong ◽  
Hongzhou Shen ◽  
...  

This study is aimed at determining the optimal sinus augmentation approach considering the poor bone condition in the zone of atrophic posterior maxilla. A series of simplified maxillary segment models varying in residual bone height (RBH) and bone quality were established. A 10 mm standard implant combined with two types of maxillary sinus augmentation methods was applied with the RBH, which was less than 10 mm in the maxilla. The maximal equivalent von Mises (EQV) stress in residual bone was evaluated. Bone quality had an enormous impact on the stress magnitude of supporting bone. Applying sinus augmentation combined with grafts was suitable for stress distribution, and high-stiffness graft performed better than low-stiffness one. For 7 mm and 5 mm atrophic maxilla, nongrafted maxillary sinus augmentation was feasible in D3 bone. Poor bone quality was a negative factor for the implant in the region of atrophic posterior maxilla, which could be improved by grafts. Meanwhile, the choice of maxillary sinus augmentation approaches should be determined by the RBH and quality.


2015 ◽  
Vol 41 (2) ◽  
pp. e1-e6 ◽  
Author(s):  
Shihab A. Romeed ◽  
Robert Nigel Hays ◽  
Raheel Malik ◽  
Stephen M. Dunne

Placement of zygomatic implants lateral to the maxillary sinus, according to the extrasinus protocol, is one of the treatment options in the rehabilitation of severely atrophic maxilla or following maxillectomy surgery in patients with head and neck cancer. The aim of this study was to investigate the mechanical behavior of a full-arch fixed prosthesis supported by 4 zygomatic implants in the atrophic maxilla under occlusal loading. Results indicated that maximum von Mises stresses were significantly higher under lateral loading compared with vertical loading within the prosthesis and its supporting implants. Peak stresses were concentrated at the prosthesis-abutments interface under vertical loading and the internal line angles of the prosthesis under lateral loading. The zygomatic supporting bone suffered significantly lower stresses. However, the alveolar bone suffered a comparatively higher level of stresses, particularly under lateral loading. Prosthesis displacement under vertical loading was higher than under lateral loading. The zygomatic bone suffered lower stresses than the alveolar bone and prosthesis-implant complex under both vertical and lateral loading. Lateral loading caused a higher level of stresses than vertical loading.


2020 ◽  
Vol 28 (6) ◽  
pp. 603-613 ◽  
Author(s):  
Efe Can Sivrikaya ◽  
Mehmet Sami Guler ◽  
Muhammed Latif Bekci

BACKGROUND: Zirconia has become a popular biomaterial in dental implant systems because of its biocompatible and aesthetic properties. However, this material is more fragile than titanium so its use is limited. OBJECTIVES: The aim of this study was to compare the stresses on morse taper implant systems under parafunctional loading in different abutment materials using three-dimensional finite element analysis (3D FEA). METHODS: Four different variations were modelled. The models were created according to abutment materials (zirconia or titanium) and loading (1000 MPa vertical or oblique on abutments). The placement of the implants (diameter, 5.0 × 15 mm) were mandibular right first molar. RESULTS: In zirconia abutment models, von Mises stress (VMS) values of implants and abutments were decreased. Maximum and minimum principal stresses and VMS values increased in oblique loading. VMS values were highest in the connection level of the conical abutments in all models. CONCLUSIONS: Using conical zirconia abutments decreases von Mises stress values in abutments and implants. However, these values may exceed the pathological limits in bruxism patients. Therefore, microfractures may be related to the level of the abutment.


2013 ◽  
Vol 24 (6) ◽  
pp. 635-641 ◽  
Author(s):  
Sandra Lucia Dantas de Moraes ◽  
Fellippo Ramos Verri ◽  
Joel Ferreira Santiago Junior ◽  
Daniel Augusto de Faria Almeida ◽  
Caroline Cantieri de Mello ◽  
...  

The purpose of this study was to assess the influence of the crown height of external hexagon implants on the displacement and distribution of stress to the implant/bone system, using the three-dimensional finite element method. The InVesalius and Rhinoceros 4.0 softwares were used to generate the bone model by computed tomography. Each model was composed of a bone block with one implant (3.75x10.0 mm) with external hexagon connections and crowns with 10 mm, 12.5 mm and 15 mm in height. A 200 N axial and a 100 N oblique (45°) load were applied. The models were solved by the NeiNastran 9.0 and Femap 10.0 softwares to obtain the results that were visualized by maps of displacement, von Mises stress (crown/implant) and maximum principal stress (bone). The crown height under axial load did not influence the stress displacement and concentration, while the oblique loading increased these factors. The highest stress was observed in the neck of the implant screw on the side opposite to the loading. This stress was also transferred to the crown/platform/bone interface. The results of this study suggest that the increase in crown height enhanced stress concentration at the implant/bone tissue and increased displacement in the bone tissue, mainly under oblique loading.


2013 ◽  
Vol 07 (04) ◽  
pp. 484-491 ◽  
Author(s):  
Wagner Moreira ◽  
Caio Hermann ◽  
Jucélio Tomás Pereira ◽  
Jean Anacleto Balbinoti ◽  
Rodrigo Tiossi

ABSTRACT Objective: The purpose of this study was to evaluate the mechanical behavior of two different straight prosthetic abutments (one- and two-piece) for external hex butt-joint connection implants using three-dimensional finite element analysis (3D-FEA). Materials and Methods: Two 3D-FEA models were designed, one for the two-piece prosthetic abutment (2 mm in height, two-piece mini-conical abutment, Neodent) and another one for the one-piece abutment (2 mm in height, Slim Fit one-piece mini-conical abutment, Neodent), with their corresponding screws and implants (Titamax Ti, 3.75 diameter by 13 mm in length, Neodent). The model simulated the single restoration of a lower premolar using data from a computerized tomography of a mandible. The preload (20 N) after torque application for installation of the abutment and an occlusal loading were simulated. The occlusal load was simulated using average physiological bite force and direction (114.6 N in the axial direction, 17.1 N in the lingual direction and 23.4 N toward the mesial at an angle of 75° to the occlusal plan). Results: The regions with the highest von Mises stress results were at the bottom of the initial two threads of both prosthetic abutments that were tested. The one-piece prosthetic abutment presented a more homogeneous behavior of stress distribution when compared with the two-piece abutment. Conclusions: Under the simulated chewing loads, the von Mises stresses for both tested prosthetic-abutments were within the tensile strength values of the materials analyzed which thus supports the clinical use of both prosthetic abutments.


2014 ◽  
Vol 607 ◽  
pp. 713-716
Author(s):  
Wen Liang Tang ◽  
Chun Yue Huang ◽  
Tian Ming Li ◽  
Ying Liang ◽  
Guo Ji Xiong ◽  
...  

In this paper, ANSYS-LSDYNA simulation software is used to build the three-dimensional finite element model of the ball bond and to get the Von Mises stress. The change of stress about the bump is researched which base on the model in different bonding pressure, bonding power and bonding time. The result show that: The stress increase with bonding pressure increase within a certain bonding pressure range, and then the stress will maintain a table number, however, the stress will continue to increase when the bonding pressure reach a certain value; increasing the bonding power, the area of lager stress will grow; prolonging the bonding time, the stress of the pad will increase with time, but when time increase to a certain value, the stress of the pad will not increase over time.


2020 ◽  
Vol 8 (1) ◽  
pp. 29-46
Author(s):  
S. Rakshe ◽  
S. V. Nimje ◽  
S. K. Panigrahi

A review on optimization of adhesively bonded spar-wingskin joint (SWJ) of laminated fiber reinforced polymer (FRP) composites subjected to pull-off load is presented in this article using three-dimensional finite element analysis. Von Mises stress components have been computed across the width of joint at different interfaces viz. load coupler-spar, and load coupler-wingskin interfaces. Further, the weight of SWJ structure is considered as the objective function which needs to be minimized for optimization. In the first step, the material and lamination scheme of the FRP composite materials used for SWJ are optimized, and, in the second step, the geometrical parameters have been optimized on the basis of minimum von Mises stress and weight. Further, the effects of the material, lamination scheme, and geometrical parameters on the von Mises stress and weight have been validated using the Analysis of Variance (ANOVA) approach as prescribed by the Taguchi method. The results show that the material and spar thickness are the most significant factors influencing von Mises stress. The weight analysis reveals that there is a significant effect of change in material and wingskin thickness on SWJ performance. Suitable design recommendations have been made for SWJ in terms of material, lamination scheme and geometrical parameters.


Author(s):  
Mateus Favero Barra Grande ◽  
Marcelo Lucchesi Teixeira ◽  
André Antônio Pelegrine ◽  
Guilherme Da Rocha Scalzer Lopes ◽  
Julio Ferraz Campos ◽  
...  

The effect of the different dental implants positioning region on the stress performance of the implant-supported prosthesis is not yet clear. This study evaluated the dental treatment with six dental implants in three different models and three different occlusal loading conditions, in terms of the biomechanical response of implants, prosthetic screw and maxilla, using three-dimensional finite element analysis. The finite element models were modelled containing external hexagon implants, as well as a Cobalt-Chromium superstructure. Three types of loads were applied: in the area of ​​the central incisors, first premolar and in the second molars. For the finite element simulations, the von-Mises stress peaks in the implant and in the surrounding cortical bone were analyzed. All recorded results reported higher values ​​for the implant-supported prosthesis in group C compared to the groups A and B. The highest stress values, ​​regardless the evaluated model, was in the prosthesis in group C and in screws, the smallest were in group A.


2017 ◽  
Vol 34 (5) ◽  
pp. 591-600
Author(s):  
D. S. Liu ◽  
C. J. Lu ◽  
S. H. Chen ◽  
C. S. Liu ◽  
T. W. Liao

AbstractThe autofocusing (AF) performance of cell phone cameras is critically dependent on the design of the voice-coil motor (VCM) used to drive the lens module. Also, the metal springs in the AF module should combine high stiffness with a good actuation response and a light weight. The present study utilizes a reverse engineering approach to construct three-dimensional finite element models of the top and bottom springs in the VCM mechanism. Simulations are then performed to investigate the von Mises stress distribution and stiffness characteristics of the two springs given horizontal and vertical orientations of the AF module, respectively. In performing the simulations, the actuation force is computed using two different analysis methods, namely a simplify structure method and a coupled electromagnetic-structural method. It is shown that the simplify structure method has the advantages of a lower computational complexity and a more comprehensive modeling capability. A further series of simulations is thus to examine the effects of the spring shape parameters on the reaction force developed by the spring stiffness. The results show that the spring stiffness increases with an increasing thickness and a decreasing rib length. The simulation results obtained for different spring shape parameter settings are summarized in the form of a parameter design chart for predicting the reaction force given known values of the spring rib length and spring thickness.


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