Biomechanical study of the bone tissue with dental implants interaction (original) (raw)
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The effect of mechanical properties of bone in the mandible, a numerical case study
2013
Bone properties are one of the key components when constructing models that can simulate the mechanical behavior of a mandible. Due to the complexity of the structure, the tooth, ligaments, different bones etc., some simplifications are often considered and bone properties are one of them. The objective of this study is to understand if a simplification of the problem is possible and assess its influence on mandible behavior. A cadaveric toothless mandible was used to build three computational models from CT scan information: a full cortical bone model; a cortical and cancellous bone model, and a model where the Young's modulus was obtained as function of the pixel value in a CT scan. Twelve muscle forces were applied on the mandible. Results showed that although all the models presented the same type of global behavior and proximity in some locations, the influence of cancellous bone can be seen in strain distribution. The different Young's modulus defined by the CT scan gray scale influenced the maximum and minimum strains. For modeling general behavior, a full cortical bone model can be effective. However, when cancellous bone is included, maximum values in thin regions increase the strain distribution. Results revealed that when properties are assigned to the gray scale some peaks could occur which did not represent the real situation.
Modelling of mandible bone properties in the numerical analysis of oral implant biomechanics
Computer Methods and Programs in Biomedicine, 2010
c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 1 0 0 ( 2 0 1 0 ) 158-165 Finite element analysis a b s t r a c t The biomechanical efficiency of oral implants is deeply influenced by mechanical properties of cortical and trabecular bone in the jaw and, in particular, in the peri-implant region. When the mechanical response of the implant-bone system is analysed by means of numerical models, the effective mechanical properties of bone and the possible change as a function of spatial position must be carefully considered. The procedure presented provides for the attribution of the mechanical properties of bone, considered as anisotropic elastic material, as a function of the spatial position making use of Fourier series and polynomial functions. The procedure is implemented in a general purpose finite element software, adopted to develop biomechanical analyses of prosthetic systems. This procedure allows for an accurate representation of bone tissue properties. Results pertaining to the analysis of commercial oral implants show the potential of the method adopted.
Stress Distribution in Mandible Regulated by Bone and Dental Implant Parameters: Part I-Methodology
2011
The complicated interrelationships between mandibular bone components and dental i mplants have attracted the attention of many a structural mechanics researcher as well as many a dental practitioner. This paper describes the methodology and analysis techniques e mployed to enable accurate evaluation of a vast range of the implant and bone parameters. The complex material and geometric properties of the bone and implant are mode lled using two-dimensional (2D) triangular a nd quadrilateral plane strain elements. Assumptions made in the analysis include: (a) 50% osseointegration between bone and implant; (b) linear relatio nships exist between the stress value and the Young's moduli of the cancellous and cortical bone at any s pecific point. In the companion paper (Part II) various bone, implant and loading parameters are evaluated for their influence on the stress distribution within the bone, i n particular in the mandible.
FEM and BEM Stress Analysis of Mandibular Bone Surrounding a Dental Implant
The Open Mechanical Engineering Journal, 2015
In the present work the structural behaviour of a mandible with a dental implant, considering a unilateral occlusion, is numerically analysed by means of the Finite Element Method (FEM) and the Boundary Element Method (BEM). The mandible, whose CAD model was obtained by computer tomography scans, is considered as completely edentulous and only modelled in the zone surrounding the implant. The material behaviour of bone is assumed as isotropic linear elastic or, alternatively, as orthotropic linear elastic. With reference to the degree of osteo-integration between the implant and the mandibular bone, a partial osteo-integration is considered; consequently a nonlinear contact analysis is performed, with allowance for friction at the interface between implant and bone. A model of a commercial dental implant is digitised by means of optical 3D scanning process and fully reconstructed in all its geometrical features. Special attention is drawn to the mathematical reconstruction of the CA...
The International journal of oral & maxillofacial implants
The complicated relationships between mandibular bone components and dental implants have attracted the attention of structural mechanics researchers as well as dental practitioners. Using the finite element method, the present study evaluated various bone and implant parameters for their influence on the distribution of von Mises stresses within the mandible. Various parameters were considered, including Young's modulus of cancellous bone, which varies from 1 to 4 GPa, and that of cortical bone, which is between 7 and 20 GPa. Implant length (7, 9, 11, 13, and 15 mm), implant diameter (3.5, 4.0, 4.5, and 5.5 mm), and cortical bone thickness (0.3 to 2.1 mm) were also considered as parameters. Assumptions made in the analysis were: modeling of the complex material and geometric properties of the bone and implant using two-dimensional triangular and quadrilateral plane strain elements, 50% osseointegration between bone and implant, and linear relationships between the stress value ...
European Journal of Dentistry
Objective The purpose of this study was to compare methods used for calculating heterogeneous patient-specific bone properties used in finite element analysis (FEA), in the field of implant dentistry, with the method based on homogenous bone properties. Materials and Methods In this study, three-dimensional (3D) computed tomography data of an edentulous patient were processed to create a finite element model, and five identical 3D implant models were created and distributed throughout the dental arch. Based on the calculation methods used for bone material assignment, four groups—groups I to IV—were defined. Groups I to III relied on heterogeneous bone property assignment based on different equations, whereas group IV relied on homogenous bone properties. Finally, 150 N vertical and 60-degree-inclined forces were applied at the top of the implant abutments to calculate the von Mises stress and strain. Results Groups I and II presented the highest stress and strain values, respective...
Computer Methods in Biomechanics and Biomedical Engineering, 2004
In cranio-maxillofacial surgery planning and implant design, it is important to know the elastic response of the mandible to load forces as they occur, e.g., in biting. The goal of the present study is to provide a method for a quantitative determination of material parameters for the human jaw bone, whose values can, e.g., be used to devise a prototype plastic model for the mandible. Non-destructive load experiments are performed on a cadaveric mandible using a specially designed test bed. The identical physiological situation is simulated in a computer program. The underlying mathematical model is based on a two component, linear elastic material law. The numerical realization of the model, difficult due to the complex geometry and morphology of the mandible, is via the finite element method. Combining the validated simulation with the results of the tests, an inverse problem for the determination of Young's modulus and the Poisson ratio of both cortical and cancellous bone can then be solved.
Finite element simulation of bone remodelling in the human mandible surrounding dental implant
Acta Mechanica, 2011
Modern dental implant is a biocompatible titanium device surgically placed into a jawbone to support a prosthetic tooth crown in order to replace missing teeth. Implants are superior to conventional prostheses, in both function and long-term predictability. However, placement of an implant changes the normal mechanical environment of jawbone, which causes the bone density to redistribute and adapt to the new environment through a process of remodelling. This study aims to predict the density distribution in human jawbone around osseointegrated dental implant. Based on two popular, yet distinctive theories for bone remodelling, a new remodelling algorithm is proposed. The proposed algorithm is verified by a two-dimensional (2D) plate model. Then, a 2D finite element model of implant and jawbone is studied. The effects of two parameters, viz the reference value of strain energy density (SED) and 'lazy zone' region, on density distribution, are also examined. This study has demonstrated that consideration of the lazy zone, is less important than consideration of the stress and strain (quantified as SED) induced within the bone. Taking into account both 'lazy zone' effect and self-organisational control process, the proposed bone remodelling algorithm has overcome the shortcomings of the two existing theories.
Dental implantation is a very useful method for edentulism treatment. After the implantation surgery, processes known as bone remodeling and osseointegration take place in which the interface strength, as well as the surrounding bone quality improves. This will have direct impact on the mechanical stress and strain in the bony tissues. This paper aims to quantify the magnitude of mechanical stress and strain developed in the bony tissues. Hence compare the stress and strain progression at different healing stages. Unlike existing studies, this investigation takes into account the effect of changing material properties due to bone remodelling. Computerized tomography (CT) scan technology was employed to construct the 3D finite element model. The mechanical response of the bone tissues was observed and the results revealed the changes in mechanical stress and strain patterns in the bone tissues at various healing stage.