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1
Content available Effect of the material’s stiffness on stress-shielding in osseointegrated implants for bone-anchored prostheses: a numerical analysis and initial benchmark data
Prochor Piotr
Acta of Bioengineering and Biomechanics
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2020
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Vol. 22, no. 2
69--81
EN
This study attempted to establish the link between design of implants for bone-anchored prostheses and stress-shielding, affecting the stability of the bone-implant coupling using numerical approach. The objectives were to share a numerical model capable to evaluate the long-term stability of implants and to use this model to extract data sets showing how shape and material stiffness of threaded, press-fit and modular press-fit implants affect stress-shielding intensity. Methods: Three designs were considered: threaded, press-fit and modular press-fit. The effect of shape and material stiffness of each design on stress-shielding intensity was assessed using Young’s modulus (10 to 210 GPa). Furthermore, the impact of the diameter of percutaneous part (10 to 18 mm) and thickness of medullar part (5 to 1 mm) was investigated for the modular press-fit implant. Results: The threaded design generated 4% more bone mass loss at the distal femur but an overall loss of bone mass was by 5% lower to press-fit design. The influence of Young’s modulus on bone mass changes was noticeable for modular press-fit implant, depending on diameter of percutaneous or medullary part. A 20 GPa change of stiffness caused a bone mass change from 0.65% up to 2.45% and from 0.07% up to 0.32% for percutaneous parts with 18 mm and 10 mm diameter, respectively. Conclusions: Results suggested that threaded implant provides greater stability despite an increased bone loss at the distal femur. Altogether, this work provided an initial model that could be applied in subsequent studies on the long-term stability of current and upcoming implants.
2
Content available Variable order 3D models of bone remodelling
Valério D., Neto J., Vinga S.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2019
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Vol. 67, nr 3
501--508
EN
This paper presents simulations of a three-dimensional model of the bone remodelling process. The model consists of a set of variable order partial differential equations, in which the varying order depends on the presence of tumour cells. The simulations are of a two-dimensional bone, to make visualisation simpler. They show that this model corresponds to the known evolution of bone remodelling, and is simpler than integer order models found in the literature.
3
Content available Role of initial density distribution in simulations of bone remodeling around dental implants
Nutu E.
Acta of Bioengineering and Biomechanics
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2018
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Vol. 20, no. 4
23--31
EN
In this paper, the effect of initial density distribution upon the predicted density via numerical simulations of bone remodeling was evaluated. The main purpose was to correlate the numerical results with clinical data according to which the initial bone quantity is an essential factor for long term survival of dental implants. Methods: Two-strain energy density-based bone remodeling theories were employed, one which accounts for overload resorption and the second one, which does not. The remodeling parameters were derived from the mechanostat theory. Bone remodeling around an osseointegrated dental implant was simulated based on finite element method using a generic mandible plane model. A variable time step was introduced to increase the speed of the remodeling simulations by keeping the truncation errors small. The simulations were performed for several initial density distributions correlated with values from clinical classifications of bone quality. For each density value, the occlusal load was defined in two ways so that to consider normal and overload mastication forces, respectively. Results: The results showed that the initial density distribution influences the predictions of bone remodeling simulations. For the analyzed model, the remodeling algorithm predicted overload resorption only in the case of low initial density, which can be associated with low bone quality, which, from clinical perspective, may probably lead to implant loss. Conclusions: The paper demonstrated that when simulating bone remodeling around dental implants using finite element method, it is important to account for initial density distribution in correlation with the bone quantity.
4
Content available Safe rebuilding of the periodontal loss an experimental study
Minch L. E., Słowiński J. J., Scigala K., Będziński R., Kawala B.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2015
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Vol. 63, nr 2
527--532
EN
This study aimed at the simulation of bone tissue remodeling within a bone defect with the utilization of the finite element method (FEM), enabling - via elaborated application - objective evaluation of orthodontic forces which positively influence periodontium in vivo. The initial position of each bracket on the passive archwire was registered, and then a geometrical and discretemodel of the appliance was created automatically. Assessment of the dental scans obtained using cone beam computed tomography (CBCT) allowed evaluation of the range of bracket displacement: from the initial position to the final one achieved on the active archwire. Those displacements established terminal conditions in the finite element analysis, enabling calculation of orthodontic force levels. An individual design of a tooth with periodontal ligaments and the periodontal defect subsequently loaded with the determined forces allowed simulation of bone remodeling according to Carters adaptation process. Mainly, the bone apposition processes took place in the central part of the periodontal defect, in proximity of the alveolar ridge. However, FEM application in the analysis of bone tissue regeneration within bone defects enables precise evaluation of the achieved changes, therefore allows determination of orthodontic forces positively influencing periodontium in vivo.
5
Content available Probabilistic study of bone remodeling using finite element analysis
Werner C., Gorla R. S. R.
International Journal of Applied Mechanics and Engineering
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2013
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Vol. 18, no. 3
911--921
EN
The dynamic bone remodeling process is a computationally challenging research area that struggles to understand the actual mechanisms. It has been observed that a mechanical stimulus in the bone greatly affects the remodeling process. A 3D finite element model of a femur is created and a probabilistic analysis is performed on the model. The probabilistic analysis measures the sensitivities of various parameters related to the material properties, geometric properties, and the three load cases defined as Single Leg Stance, Abduction, and Adduction. The sensitivity of each parameter is based on the calculated maximum mechanical stimulus and analyzed at various values of probabilities ranging from 0.001 to 0.999. The analysis showed that the parameters associated with the Single Leg Stance load case had the highest sensitivity with a probability of 0.99 and the angle of the force applied to the joint of the proximal femur had the overall highest sensitivity.
6
Content available Ocena histologiczna i radiologiczna kości królików po implantacji kompozytu CHAP-glukan
Borkowski L., Pawłowska M., Polkowska I., Karpiński M., Słowik T., Piersiak T., Matuszewski Ł., Ślósarczyk A., Ginalska G.
Engineering of Biomaterials
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2012
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Vol. 15, no. 114
28--33
PL
W eksperymencie in vivo zbadano podstawowe cechy dwufazowego kompozytu kościozastępczego tj. biozgodność i osteokonduktywność, a także jego właściwości osteoindukcyjne. Testowany kompozyt, przeznaczony do wypełniania ubytków kostnych, został wykonany z granul hydroksyapatytu węglanowego i polimeru polisacharydowego. Biomateriał został wszczepiony do kości piszczelowych królików na okres 1 lub 3 miesięcy. Po tym czasie zbadano stopień regeneracji kości na podstawie badań makroskopowych (radiologicznych) i mikroskopowych. Stwierdzono zaawansowane procesy osteointegracji i przebudowy kostnej w okolicy implantu, co wskazuje zarówno na osteokonduktywne, jak i osteoindukcyjne właściwości badanego biomateriału.
EN
Basic characteristics of a hydroxyapatite-glucan biomaterial such as biocompatibility, osteoconductivity and osteoinductive properties were tested in in vivo experiment. The two-phase composite, intended for filling bone defects, was made of carbonated hydroxyapatite granules and polysaccharide polymer. The biomaterial was implanted to the tibial metaphysis in rabbits for the 1- or 3-month period. Bone regeneration after that time was evaluated by radiology and histology. Our analysis showed advanced osseointegration and extensive bone remodelling in the direct vicinity of implants indicating osteoinductive and osteoconductive properties of the material studied.
7
Content available remote The meaning of the piezoelectric and streaming potential in bone remodeling
Lech Ł., Iwaniec M.
Vibrations in Physical Systems
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2010
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Vol. 24
251--258
EN
In this paper authors include the most important information about piezoelectric effect and streaming potential occurring in bone. In their opinion these phenomena play important role during bone remodeling, so that model binding them together was proposed. Model describes mechanisms responsible for “sensing” by osteocyteslocal changes in stresses and strains and for signal transmissions from sensors to effectors i.e. osteoblasts.
PL
W pracy tej zawarto najważniejsze informacje dotyczące występowania efektu piezoelektrycznego oraz potencjału przepływu w strukturach kostnych, które zdaniem autorów tego tekstu, ma odgrywa ważną rolę przy przebudowie tkanki kostnej. Dlatego został zaproponowany model odbierania sygnałów o stanie mechanicznym kości przez osteocyty i powiązany z modelem oddziaływań międzykomórkowych opisującym przekazywanie informacji z osteocytów do osteoblastów.
8
Content available remote On some properties of bone functional adaptation phenomenon useful in mechanical design
Nowak M.
Acta of Bioengineering and Biomechanics
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2010
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Vol. 12, no. 2
49-54
EN
The paper discusses some unique properties of trabecular bone functional adaptation phenomenon, useful in mechanical design. On the basis of the biological process observations and the principle of constant strain energy density on the surface of the structure, the generic structural optimisation system has been developed. Such approach allows fulfilling mechanical theorem for the stiffest design, comprising the optimisations of size, shape and topology, using the concepts known from biomechanical studies. Also the biomimetic solution of multiple load problems is presented.
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