How do tissues respond and adapt to stresses around a prosthesis? A primer on finite element stress analysis for orthopaedic surgeons (original) (raw)
Related papers
Local stresses and bone adaption around orthopedic implants
Calcified Tissue International, 1984
The severest long-term complications of orthopedic joint-prostheses are associated with loosening of the implant-bone interface, due to adverse reactions in bone and subsequent weakening of the connection between the two materials. Mechanical stresses, caused by joint loading, play a key role in the adaption of interface bone and in the loosening process, In the present study, it is shown how local interface stress patterns can be evaluated using advanced methods of computer-based, engineering stress analyses (the Finite Element Method, FEM). The stress patterns are compared with the local bone structure and bone resorption phenomena as found in animal experiments. The results indicate that loosening and bone resorption is associated with high peak stresses at the interface in the immediate postoperative stage. In addition, there appears to be similarity between the local stress patterns and the bone morphology at the interface if resorption does not occur. Finally, it is found that implants of high local stiffness generate lower peak stresses in bone, as compared with low stiffness implants.
Journal of Dental Sciences, 2011
Background/purpose: The design and materials of a prosthesis affect the loading of dental implants and deformation of the bone. The aim of the study was to evaluate the effects of prosthesis design and materials on the stress distribution of implant-supported prostheses. Materials and methods: A 3-dimensional finite element analysis method was selected to evaluate the stress distribution in the bone. Three different models were designed as follows: a 3-unit implant-supported fixed partial denture (FPD) composed of a metal framework and porcelain veneer with (M2) or without a cantilevered extension (M1) and an FPD composed of a fiber-reinforced composite (FRC) framework and a particulate composite veneer without a cantilevered extension (M3). In separate load cases, 300-N vertical, 150-N oblique, and 60-N horizontal forces were applied to the prostheses in the models. von Mises stress values in the cortical and cancellous bone were calculated. Results: In cortical bone, the highest von Mises stresses were noted in the M2 Model with a vertical load; whereas, higher stresses were observed in the M1 Model with horizontal and oblique loads. The lowest stress values were determined in the M3 Model for all loading conditions. In cancellous bone, decreased stress values were found with all 3 models under the applied loads. Conclusions: Prosthesis design and materials affect the load-transmission mechanism. Although additional experimental and clinical studies are needed, FRC FPDs can be considered a suitable alternative treatment choice for implant-supported prostheses. Within the
The International Journal of Oral Maxillofacial Implants, 2010
PURPOSE: Using the three-dimensional finite element method (FEM), this study compared the biomechanical behavior of the "All-on-Four" system with that of a six-implant-supported maxillary prosthesis with tilted distal implants. The von Mises stresses induced on the implants under different loading simulations were localized and quantified.MATERIALS AND METHODS: Three-dimensional models representing maxillae restored with an "All-on-Four" and with a six-implant-supported prosthesis were developed in three-dimensional design software and then transferred into FEM software. The models were subjected to four different loading simulations (full mouth biting, canine disclusion, load on a cantilever, load in the absence of a cantilever). The maximum von Mises stresses were localized and quantified for comparison.RESULTS: In both models, in all loading simulations, the peak stress points were always located on the neck of the distal tilted implant. The von Mises stress values were higher in the "All-on-Four" model (7% to 29%, higher, depending on the simulation). In the presence of a cantilever, the maximum von Mises stress values increased by about 100% in both models.CONCLUSIONS: The stress locations and distribution patterns were similar in the two models. The addition of implants resulted in a reduction of the maximum von Mises stress values. The cantilever greatly increased the stress.
Journal of Craniofacial Surgery, 2010
This finite element analysis study evaluated the optimal material combination for the superstructure of single implantsupported prosthesis with different fit patterns. Two models of a twodimensional finite element analysis were constructed: group A (control), prosthesis presenting precise fit to implant; and group B, prostheses with unilateral angular misfit of 100 Km. Each group was divided into 5 subgroups according to different materials for framework (gold alloy, titanium, and zirconia) and veneering (porcelain and modified composite resin). Evaluation was performed on ANSYS software with 133-N load applied at the opposite side of misfit on the model. The load was applied with a 30-degree angulation and 2-mm off-axis. The presence of unilateral angular misfit (group B) increased the von Mises stresses in the implant (40%) and retention screw (7%) in comparison to group A. The combination of porcelain/titanium and porcelain/zirconia displayed more favorable stress distribution. When gold alloy was used as a framework material, there was no difference in stress values for both veneering materials in all groups. The use of stiffer and softer superstructures materials did not affect the stress distribution and stress values in the supporting tissue. According to the biomechanical point of view, materials with high elasticity modulus are more suitable for the superstructure of implant-supported prosthesis.
Finite‐Element Analysis of Stress on Dental Implant Prosthesis
Clinical Implant Dentistry and Related Research, 2009
ABSTRACTBackground: Understanding how clinical variables affect stress distribution facilitates optimal prosthesis design and fabrication and may lead to a decrease in mechanical failures as well as improve implant longevity.Purpose: In this study, the many clinical variations present in implant‐supported prosthesis were analyzed by 3‐D finite element method.Materials and Method: A geometrical model representing the anterior segment of a human mandible treated with 5 implants supporting a framework was created to perform the tests. The variables introduced in the computer model were cantilever length, elastic modulus of cancellous bone, abutment length, implant length, and framework alloy (AgPd or CoCr). The computer was programmed with physical properties of the materials as derived from the literature, and a 100N vertical load was used to simulate the occlusal force. Images with the fringes of stress were obtained and the maximum stress at each site was plotted in graphs for compa...
International Journal of Engineering and Applied Sciences, 2020
Dental implant applications for edentulous jaws are today considered a predictable, safe, and daily technique for giving patients new aesthetics and function. However, the success of the implant therapy should be thoroughly investigated for long-term clinical results about the stress distribution in hosting bone tissue and prosthetic components. In this study, the effect of different prosthesis designs on the stress distribution around the abutment and dental implant in bone tissue was investigated using the finite element method (FEM) with Workbench module of the ANSYS package program. The examination focuses on the effect of the number of implants in teeth layouts on the distribution of stresses, strains, and displacements. In the study the historical development of dental implant problems is mentioned, and some previous studies are summarized. Critical information is also given about biomechanics, dental implants, jawbone, teeth, and the finite element method. Totally four differ...
Dental Journal of Advance Studies
Introduction This study was undertaken to evaluate the pattern of stress distribution in implant body and surrounding bone with and without splinting of implant prostheses when subjected to occlusal loading, using the finite element analysis. Methods The geometric models of implant and mandibular bone were generated. Two models were created in accordance with the need of the study. The first model was given a two implant in the first mandibular molar and second premolar with splinted prosthesis. Then, second model was given two such implants in the same region but without splinting the prosthesis. Forces of 100 N and 50 N were applied axially and buccolingually, respectively. Results The maximum von Mises stress values with axial force of the implant splinted prosthesis were observed to be 4.21 MPa for cortical bone, 0.88 MPa for cancellous bone, and 10.592 MPa for implant body. The maximum von Mises stress values with buccolingual force of the implant splinted prosthesis were obser...
The Long-Term Behaviour of Human Joints with Orthopedic Prostheses: Finite Element Models
2000
In the short-term, clinical problems after non-cemented total joint replacement are caused by initial instability of implant (high relative micro motions of the implant with respect to the host bone) which may lead to late aseptic loosening. Failure is mainly due to the inhibition of interface bone ingrowth and to the change of bone into a fibrous tissue encapsulating the