Effect of Varying Diameter of Dental Implants During Placements in Compromised Bony Ridges at Different Insertion Torques: A Finite Element Study

Author(s):  
Imran Aziz ◽  
Waleed A. Khan ◽  
Faisal Moeen ◽  
Imran Akhtar ◽  
Wasim Tarar

The life of dental implant depends on various parameters such as insertion torque, implant diameter and cortical and cancellous bones thickness. The thickness of the cortical and cancellous bones varies from patient to patient and for each thickness, the corresponding studies are required to determine the favorable implant loading. In this study, stress analysis on various dental implant fixtures inserted in compromised bony ridges is performed using three dimensional finite element analyses. Initially, the modeling and analysis of previously analyzed structure is done to validate the solution procedure. After successful validation, three dimensional linear elastic analysis of bone implant bone assembly is performed. The implant material is treated as isotropic whereas the bone materials are taken as anisotropic materials. The parametric study finds the effect of insertion torque and variation of implant diameter on stress induced in the compromised bony ridge. Further, the implant bone assembly was analyzed using various cortical bone thicknesses. It has been observed that the increase in torque results in increased stress and deformation in the bone. With increasing bone thickness, the similar variation of torque produces less stress and deformation in dental implants. The study is helpful in prediction of favorable implant loading and implants diameters for compromised bony ridges. The study provides useful knowledge in improving the performance and life of dental implants.

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaoning Kang ◽  
Yiming Li ◽  
Yixi Wang ◽  
Yao Zhang ◽  
Dongsheng Yu ◽  
...  

Occlusal trauma caused by improper bite forces owing to the lack of periodontal membrane may lead to bone resorption, which is still a problem for the success of dental implant. In our study, to avoid occlusal trauma, we put forward a hypothesis that a microelectromechanical system (MEMS) pressure sensor is settled on an implant abutment to track stress on the abutment and predict the stress on alveolar bone for controlling bite forces in real time. Loading forces of different magnitudes (0 N–100 N) and angles (0–90°) were applied to the crown of the dental implant of the left central incisor in a maxillary model. The stress distribution on the abutment and alveolar bone were analyzed using a three-dimensional finite element analysis (3D FEA). Then, the quantitative relation between them was derived using Origin 2017 software. The results show that the relation between the loading forces and the stresses on the alveolar bone and abutment could be described as 3D surface equations associated with the sine function. The appropriate range of stress on the implant abutment is 1.5 MPa–8.66 MPa, and the acceptable loading force range on the dental implant of the left maxillary central incisor is approximately 6 N–86 N. These results could be used as a reference for the layout of MEMS pressure sensors to maintain alveolar bone dynamic remodeling balance.


2013 ◽  
Vol 470 ◽  
pp. 962-965
Author(s):  
Dong Yan Ding ◽  
Jian Min Ren

The Chengzigou hydropower station of composite geomembrane rockfill dam as an example of the dam body and the composite geotechnical membrane stress and deformation characteristics are used nonlinear elastic model - Duncan EB model establish three-dimensional finite element model of rockfill,by using the large finite element softwareFLAC3D,whice provided geogrid element to simulate lexible geomembrane shear interaction with soil.The stress and deformation of the dam and the composite geomembrane is calculated under two conditionscompletion period and impoundment period.And analyze the change of the stress and strain distribution rule,whice will provide the basis for the design of the geomembrane.


2013 ◽  
Vol 838-841 ◽  
pp. 1763-1767
Author(s):  
Shuang Mei Chang ◽  
Wen She He ◽  
Yu Qiang Cheng ◽  
Su Min Zhao

Taking the concrete face cock-fill dam upper reservoir of Tianchi as an example, the stress and deformation characteristics of concrete face rock-fill dam are studied in-depth in this paper. The article builds a fine three-dimensional finite element model of Tianchi upper reservoir by a nonlinear elastic model of the finite element software ADINA. The stress and deformation of the two conditions under completion and storage for the dam are calculated ,which will be analyzed to obtain stress - strain distribution of the dam in two conditions, comparing dam stress and deformation before and after impoundment to get impact of the water pressure on the dam stress and deformation: comparing after impoundment and completion , the dam water level displacement of upstream side from role of horizontal water pressure will increase , the dam upstream offsets to downstream , but the offset is little ; Due to dam is affected by vertical hydrostatic pressure and uplift pressure after impoundment , the dam settlement is slightly less than the completion in storage. KEY WORDS: Tianchi upper reservoir, The concrete face cock-fill dam, Three-dimensional finite element, Nonlinear elastic model, Analysis of stress and deformation


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