scholarly journals Stress Distribution on the Prosthetic Screws in the All-on-4 Concept: A Three-Dimensional Finite Element Analysis

2020 ◽  
Vol 46 (1) ◽  
pp. 3-12
Author(s):  
Ji-Hyeon Oh ◽  
Young-Seong Kim ◽  
Joong Yeon Lim ◽  
Byung-Ho Choi

The all-on-4 concept, which is used to rehabilitate edentulous patients, can present with mechanical complications such as screw loosening and fracture. The purpose of this study was to evaluate the stress patterns induced in the prosthetic screws by the different prosthetic screw and abutment designs in the all-on-4 concept using finite element analysis. Von Mises stress values on 6 groups of each screw type, including short and narrow screw, short abutment; short and wide screw, short abutment; long and wide screw, short abutment; short and narrow screw, long abutment; short and wide screw, long abutment; and long and wide screw, long abutment, were compared under a cantilever loading of 200 N that was applied on the farther posterior to the position of the connection between the distal implant and the metal framework. Posterior prosthetic screws showed higher stress values than anterior prosthetic screws. The stress values in posterior prosthetic screws decreased as the length and diameter increased. In conclusion, the long and wide screw design offers advantages in stress distribution when compared with the short and narrow design.

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 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.


2013 ◽  
Vol 405-408 ◽  
pp. 1139-1143
Author(s):  
Wei Su ◽  
Ying Sun ◽  
Shi Qing Huang ◽  
Ren Huai Liu

Using ANSYS parametric design language, a three-dimensional finite element model is developed to analyze the stress distribution and the strength of the mega columns for XRL West Kowloon Terminus. The detailed von Mises stress distribution in each column, vertical stiffener plates and the diaphragm plates is obtained. From the analysis, the phenomenon of stress concentration is obvious in both upper and lower diaphragm plates. The local value of von Mises stress in them is higher than the yield stress value, which must be avoided by more detailed local structural design.


2015 ◽  
Vol 41 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Gianpaolo Sannino

The aim of this work was to study the biomechanical behavior of an All-on-4 implant-supported prosthesis through a finite element analysis comparing 3 different tilt degrees of the distal implants. Three-dimensional finite element models of an edentulous maxilla restored with a prosthesis supported by 4 implants were reconstructed to carry out the analysis. Three distinct configurations, corresponding to 3 tilt degrees of the distal implants (15°, 30°, and 45°) were subjected to 4 loading simulations. The von Mises stresses generated around the implants were localized and quantified for comparison. Negligible differences in von Mises stress values were found in the comparison of the 15° and 30° models. From a stress-level viewpoint, the 45° model was revealed to be the most critical for peri-implant bone. In all the loading simulations, the maximum stress values were always found at the neck of the distal implants. The stress in the distal implants increased in the apical direction as the tilt degree increased. The stress location and distribution patterns were very similar among the evaluated models. The increase in the tilt degree of the distal implants was proportional to the increase in stress concentration. The 45° model induced higher stress values at the bone-implant interface, especially in the distal aspect, than the other 2 models analyzed.


2011 ◽  
Vol 1 (2) ◽  
pp. 55
Author(s):  
Özkan ADIGÜZEL ◽  
Sadullah KAYA ◽  
Senem YİĞİT ÖZER ◽  
Yalçın DEĞER ◽  
Emine GÖNCÜ BAŞARAN ◽  
...  

Aim: This study compared the stress distributions of endodontically treated tooth restored with carbon and titanium post during different loading conditions. Methodology: A 3-dimensional finite element model was created to represent an endodontically treated maxillary central incisor tooth with its supporting structures. Stress distribution and stress values were then calculated by considering the three dimensional von Mises stress criteria. Results: A 100-N static vertical occlusal load was applied on the node at the center of occlusal surface of the tooth. The von Mises stress values for carbon post model was on the coronal third and the cervical area of the root in the range of 353.149 and 13.878 MPa,  for titanium post model was 540.736 and 22.777 MPa. Conclusion: This study shows that the titanium post yields larger stresses than the carbon post.  How to cite this article: Adıgüzel Ö, Kaya S, Yiğit Özer S, Değer Y, Göncü Başaran E, Yavuz İ. Three-dimensional Finite Element Analysis of Endodontically Treated Tooth Restored with Carbon and Titanium Posts. Int Dent Res 2011;2:55-59. Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.


2021 ◽  
Vol 11 (3) ◽  
pp. 1220
Author(s):  
Azeem Ul Yaqin Syed ◽  
Dinesh Rokaya ◽  
Shirin Shahrbaf ◽  
Nicolas Martin

The effect of a restored machined hybrid dental ceramic crown–tooth complex is not well understood. This study was conducted to determine the effect of the stress state of the machined hybrid dental ceramic crown using three-dimensional finite element analysis. Human premolars were prepared to receive full coverage crowns and restored with machined hybrid dental ceramic crowns using the resin cement. Then, the teeth were digitized using micro-computed tomography and the teeth were scanned with an optical intraoral scanner using an intraoral scanner. Three-dimensional digital models were generated using an interactive image processing software for the restored tooth complex. The generated models were imported into a finite element analysis software with all degrees of freedom concentrated on the outer surface of the root of the crown–tooth complex. To simulate average occlusal load subjected on a premolar a total load of 300 N was applied, 150 N at a buccal incline of the palatal cusp, and palatal incline of the buccal cusp. The von Mises stresses were calculated for the crown–tooth complex under simulated load application was determined. Three-dimensional finite element analysis showed that the stress distribution was more in the dentine and least in the cement. For the cement layer, the stresses were more concentrated on the buccal cusp tip. In dentine, stress was more on the cusp tips and coronal 1/3 of the root surface. The conventional crown preparation is a suitable option for machined polymer crowns with less stress distribution within the crown–tooth complex and can be a good aesthetic replacement in the posterior region. Enamic crowns are a good viable option in the posterior region.


Author(s):  
Mohammed Abusaad Siddiqui ◽  
Sudheer N ◽  
Dulala Vikram Raj ◽  
Aditi Chintamani Sabnis ◽  
Alluru Amrutesh ◽  
...  

The treatment modality for completely edentulous arches has shifted from complete dentures to dental implants during the last 15-20 years. Tilting of implants has reduced the concern of resorbed posterior ridges in completely edentulous patients with “All-on-four” and “All-on-six” concept of dental implants. The purpose of this study is to compare the biomechanical behaviour of the “All-on-four”, “All-on-six” models with tilted distal implants at different angulations of 30 and 45 ° with four parallel placed implant-supported fixed prosthesis, and six parallel placed implant-supported fixed prosthesis models as controls using three-dimensional finite element analysis. The results showed that in all the models, in cancellous bone, cortical bone, implant and prosthesis – “All-on-four” model with distal implants tilted at an angulation of 30° showed stress values less than or equivalent to all the other models except on the implant in the presence of cantilever and on prosthesis during full mouth biting load where maximum stresses were observed. The study shows that All-on-four concept with tilted distal implants at an angulation of 30° showed stress values favourable for the rehabilitation of completely edentulous maxilla, but the presence of cantilever remains an area of concern.


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