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EN
The purpose of this study was to quantify the elastic properties and evaluate microscopical features of raw and boiled metatarsal bovine bone. Methods: The elastic modulus, hardness and microscopic surface of raw and cooked bovine metatarsal bone have been investigated using nanoindentation, SEM/EDX and Panasis microscope. Results: Regarding raw bovine bone, the average elastic modulus was 30.515 ± 6,769 GPa, while the average hardness was 0.5683 ± 0.211 GPa. When it comes to boiled bone corresponding values were 22.298 ± 7.0303 GPa and 0.408 ± 0.199 GPa, respectively. The values for investigated parameters were significantly higher ( p < 0.05) in raw bone specimens. Elastic modulus significantly correlated with hardness ( p < 0.05). EDX analysis revealed significant decrease in wt% of oxygen in boiled samples ( p < 0.05) No significant differences could be observed in SEM images particularly when analysing in smaller magnifications. Using higher magnification, additional branching of the existing voids as well as discrete reorganization and smoother edges of nutrient canals could be observed. The surface of boiled specimens was without the presence of crusts and layering, and no microscopical evidence of structural damage could be observed. Conclusions: This study provides detailed analysis of hardness, elastic modulus of raw and cooked bovine bone and their relation and changes during exposure to temperature. These results of elastic moduli and hardness could be comparable to similar studies of bovine and human bone tissue, but the careful analysis of experimental design, type of the bone as well as limitations of the employed techniques must be carried out before interpolation of the results to other theoretical, clinical, biomaterial and archeological studies.
2
EN
The aim of the work was to show that the fatigue load of bone tissue causes permanent structural changes in it. Methods: On the basis of the movie recording of gait, the time courses of angular changes in the joints of the lower limb were determined. Using the method of transforming Denavit–Hartenberg coordinate systems, the course of force loading the hip joint and, after that, the course of normal contact reaction of the femoral head of the knee joint during gait for the support phase were determined. On the basis of the Hertz formula, the course of contact stresses in the femoral joint head and the damage coefficient were determined according to the Palmgren–Miner damage accumulation hypothesis. Results: A calculation example was made using own software. The course of the obtained damage factor was compared to the image fixed in the X-ray image after its appropriate processing. The thesis of the work has been confirmed to a satisfactory degree. Conclusions: The nature of the lesions is similar to the image of structural changes in the head of the joint. It should be assumed that the image fixed in the bone is the result of the stored history of loads. Analysis of the obtained image can be used to determine the state of bone strength.
EN
Purpose: The conventional screw is unable to provide enough screw-bone interface strength for osteoporotic cencellous bone, and complications resulting from loosening or failure of the implants remain a significant clinical problem. Hence, the purpose of this study is to investigate pullout strength and energy in three types of the pedicle screws, including conventional solid pedicle screw, cannulated pedicle screw, and cannulated pedicle screw with a central pin, using osteoporotic sawbone test block with different bone cement volumes through pullout force testing. Methods: The control group (n = 15) of the osteoporotic sawbone test block includes groups A, B, and C to reflect three types of the pedicle screws without bone cement augmentation. The cemented group (n = 45) of the osteoporotic sawbone test block includes groups D1, D2, D3, E1, E2, E3, F1, F2, and F3 to reflect three types of the pedicle screws with PMMA bone cement of 2, 3, and 4 mL augmentation. Results: The results showed that the pullout strength and energy in the cemented group were significantly larger than that in the control group. Moreover, the best performances of the pullout strength and energy in the cemented group were evidenced obviously in the case of cannulated pedicle screw with a central pin with 4 mL bone cement augmentation. Conclusions: This study concludes that cement argumentation in the cannulated pedicle screw with a central pin can increase a pullout strength of pedicle screw for severe osteoporotic patients while bone cement of injective volume is limited.
EN
There is a need for efficient stem cell-to-tenocyte differentiation techniques for tendon tissue engineering. More than 1 week is required for tenogenic differentiation with chemical stimuli, including co-culturing. Research has begun to examine the utility of mechanical stimuli, which reduces the differentiation time to several days. However, the precise length of time required to differentiate human bone marrow-derived mesenchymal stem cells (hBMSCs) into tenocytes has not been clarified. Understanding the precise time required is important for future tissue engineering projects. Therefore, in this study, a method was developed to more precisely determine the length of time required to differentiate hBMSCs into tenocytes with cyclic stretching stimulus. Methods: First, it had to be determined how stretching stimulation affected the cells. Microgrooved culture membranes were used to suppress cell orientation behavior. Then, only cells oriented parallel to the microgrooves were selected and evaluated for protein synthesis levels for differentiation. Results: The results revealed that growing cells on the microgrooved membrane and selecting optimally-oriented cells for measurement improved the accuracy of the differentiation evaluation, and that hBMSCs differentiated into tenocytes in approximately 10 h. Conclusions: The differentiation time corresponded to the time required for cellular cytoskeleton reorganization and cellular morphology alterations. This suggests that cells, when subjected to mechanical stimulus, secrete mRNAs and proteins for both cytoskeleton reorganization and differentiation.
5
Content available The structural and mechanical properties of the bone
EN
The work contains basic information on the anatomy and physiology of bone tissue. Basic concepts related to the structure of bone tissue are presented. General issues related to bone reconstruction processes and biomechanical structural adaptations processes were described. Mechanical parameters of bone tissue were presented.
PL
Praca zawiera podstawowe informacje z zakresu anatomii i fizjologii tkanki kostnej. Przedstawiono podstawowe pojęcia związane ze strukturą tkanki kostnej. Opisano podstawowe zagadnienia związane z procesami przebudowy tkanki kostnej oraz biomechaniczne procesy dostosowawcze. Zaprezentowano parametry mechaniczne tkanki kostnej.
PL
Praca przedstawia model numeryczny kończyny górnej człowieka przydatny do analizy ryzyka złamania kości kończyny podczas upadku do przodu. W odróżnieniu od innych modeli spotykanych w literaturze, proponowany w tej pracy model uwzględnia wszystkie trzy główne kości kończyny górnej połączone powierzchniami stawowymi w stawie łokciowym i nadgarstkowym przy zastosowaniu kontaktu typu bonded jako jeden złożony układ biomechaniczny. Analizę dynamiczną przeprowadzono dla różnych konfiguracji kości przedramienia, wykorzystując dwa kryteria wytrzymałościowe do oceny potencjalnych miejsc złamań kości kończyny.
EN
The paper presents numerical model of the human upper extremity useful for the analysis of the upper extremity bones fracture risk during the falling process in a forward direction. Unlike previous models met in literature, the proposed in this paper model considers all three main upper extremity bones connected in the elbow and wrist joints by the bonded type contact as one complex biomechanical system. Transient analysis has been carried out for different forearm configurations by using two strength criteria to estimate possible sites of upper extremity bone fractures.
EN
One of the problems associated with callus distraction is a long time period needed for consolidation of the newly formed bone. The goal of this study was to determine whether percutaneous injections of rhBMP 2 in BSM would enhance bone consolidation. Methods: A unilateral tibial osteotomy combined with external stabilization was performed in 20 adult sheep. After a latency of four days, distraction was conducted for 20 days. Sheep were divided into three groups: group 1 received rhBMP-2/αBSM injections at day 23 and 30, group 2 buffer/BSM injections at day 23 and 30 and group 3 did not receive any injection. The radiographs and in-vivo torsional stiffness measurements were obtained weekly during the following 50 days. Post-mortem bone densitometry (DXA) and mechanical testing were performed. Results: In-vivo stiffness assessments, DXA values and the maximum torsional moment of the sheep tibia treated with two rhBMP-2 injections were not significantly greater than those of both control groups. Conclusions: Presented application of rhBMP-2 in BSM failed to enhance bone consolidation in distraction osteogenesis.
EN
This article is focused on the data concerning properties of carbamazepine, an antiepileptic drug commonly used in everyday medical practice but also frequently misused leading to many reported cases of intoxication. Due to high prevalence of this drug detailed data concerning its pharmacokinetics and prahmacodynamics can be found as well as metabolic paths that have been proven or have not been confirmed yet. For the purpose of toxicological analyses of samples collected postmortem it is also essential to know the possible transformations of an analyte due to microbial metabolism and postmortem changes of the sample matrix. In forensic cases of unavailable or unusable blood samples when advanced stage of decomposition processes in the found body occurs, alternative matrices are required. Presented review describes three types of such matrices: bones, bone marrow and grease in the context of their postmortem changes and suitability as the source of toxicological information.
PL
Przedstawiono wyniki prac nad otrzymywaniem granulowanych nawozów fosforowych na bazie mikrobiologicznie aktywowanych popiołów ze spalania osadów ściekowych oraz kości z przemysłu drobiarskiego. Nawozy zostały otrzymane w granulatorze bębnowym, a następnie poddane badaniom właściwości fizykochemicznych, na podstawie których oceniono jakość otrzymanych granulatów oraz wyznaczono kierunki dalszych prac nad otrzymaniem granulowanych nawozów fosforowych na bazie mikrobiologicznie aktywowanych odnawialnych źródeł fosforu.
EN
Microbiologically activated ash from the incineration of sewage sludge and bones from the poultry industry were used for prepn. P-contg. granulated fertilizers in a drum granulator. The fertilizers were tested for physicochem. and mech. properties. The fertilizers based on poultry bones showed nonsatisfactory mech. strength and the lowest content of NH₄ citrate-sol. P₂O₅.
EN
Bones, the fundamental part of the skeleton, are constantly subjected to many biological processes including growth, feeding and remodelling. Remodelling causes changes in bone structure that may be difficult to notice on a day-to-day basis but become significant over the longer time span. It acts on the cancellous and cortical bone tissue, causing alterations in thickness and spatial arrangement in the first and alternations in pore size in the second. In healthy individuals such changes are a part of the natural bone remodelling process explained by Wolff’s law. However, the direction of such changes is difficult to predict in patients in various pathological states in which bone health is affected. Here, we present a method to generate a computer based geometric model of the bone structure based on the cancellous tissue structure images. As a result we obtained a geometric model of the structure corresponding to the physical model of the cancellous bone. Such a model can be used in computer simulation to predict the remodelling changes in the healthy and pathological bone structures.
EN
Purpose: Biomechanical comparison of straight DCP and helical plates for fixation of transversal and oblique tibial bone fractures were analyzed and compared to each other by axial compression, bending and torsion tests. Method: An in vitro osteosynthesis of transverse (TF) and oblique bone fracture (OF) fixations have been analysed on fresh sheep tibias by using the DCP and helical compression plates (HP). Results: Statistically significant differences were found for both DCP and helical plate fixations under axial compression, bending and torsional loads. The strength of fixation systems were in favor of DC plating with exception of the TF-HP fixation group under compression loads and torsional moments. The transvers fracture (TF) stability was found to be higher than that found in oblique fracture (OF) fixed by helical plates (HP). However, under torsional testing, compared to conventional plating, the helical plate fixations provided a higher torsional resistance and strength. The maximum stiffness at axial compression loading and maximum torsional strength was achieved at torsional testing for the TF-HP fixations. Conclusion: From in vitro biomechanical analysis, fracture type and plate fixation system groups showed different responses under different loadings. Consequently, current biomechanical analyses may encourage the usage of helical HP fixations in near future during clinical practice for transverse bone fractures.
12
Content available Mock-up in hip arthroplasty pre-operative planning
EN
The correct estimation of stem boundary conditions in hip arthroplasty cannot be performed simply by subtracting the prosthesis volume from the bone volume: the stem implant path needs to be taken into account. Digital mock-up is a technique commonly applied in the automotive field which can be used for this aim. Given a certain femur, a stem, and an implantation path, the volume of the removed bone stock can be evaluated, as well as the final contact area between the bone and the stem, and, section by section, the residual cortical bone thickness. The technique proved to be useful: if the stem implant path is not considered, the removed bone stock volume can be underestimated up to 6%, while the contact area extension can be overestimated up to 28%. On the whole, a new methodology has been set up and tested, which can be usefully employed to accurately establish stem boundary conditions in the pre-operative planning stage, and in order to perform a reliable structural stress analysis. The methodology implemented here by experienced researchers can be made available to surgeons, setting up an apposite software suite.
EN
Restoration of mandible discontinuity defects continues as a challenge for maxillofacial surgeons. Despite the development of algorithms for reconstruction plates fixation and autogenous grafting techniques, complications are still encountered including screw loosening, bone resorption or delayed/incomplete union. The aim of the study was to analyze the possibility of obtaining bone union in the aspect of biomechanical conditions of two mandible reconstructions using an autogenous iliac crest bone graft stabilized with a reconstruction plate, and to attempt to predict patient outcomes based on strength parameters obtained by the finite element analysis. The authors of the present paper were trying to determine to what extent the reconstruction model and changes occurring in hard tissues of the bone and autogenous graft (simulated by changes in material properties) might help predict individual patient courses. The effort of reconstruction plates was defined using the values of the von Mises stress (σHMH) while the effort of bones was determined based on the values of strain intensity εint. The results of the above mentioned simulations are presented in the form of bar graphs and strain/stress distribution maps. Our strength analyses indicate that uncomplicated healing of grafts fixed with reconstruction plates requires that the initial loading of the stomatognatic system should not result in strain intensity exceeding 20–40 [×10–4]. This range of strain intensity evokes an increase in the mineral phase. The state of nonunion between the mandibular bone and the graft might result from prolonged periods of insufficient loading of the mandible during treatment.
EN
Due to temperature increase during bone drilling, bone necrosis is likely to occur. To minimize bone tissue damage during drilling, a detailed in vitro experimental study by using fresh calf cortical bones has been performed with various combined drilling parameters, such as: drilling environment, drill diameter, drill speed, drill force, feed-rate and drill coating. Bone temperatures at the drilling sites were recorded with high accuracy using multi-thermocouples mounted around the tibial diaphyseal cortex. It was shown that temperatures increased with increased drill speeds. It also decreased with a higher feed-rate and drill force. It was also observed that TiBN coated drills caused higher temperatures in the bone than the uncoated drills and the temperatures increased with larger drill diameters. Although the influence of Simulated Body Fluid (SBF) on rising temperatures during drilling was higher for the TiBN coated drills, it was observed that these drills caused more damage to the bone structure. In order to minimize or avoid bone defects and necrosis, orthopaedic surgeons should consider the optimum drilling parameters.
EN
The development of orthodontics has improved thanks to the introduction of adhesives which are physically and chemically akin to tooth enamel and brackets. These materials often fall short of the required durability standards. The objective was to evaluate the real strength of the adhesives and to introduce a proprietary device, generating multiple vectors of strength between dental brackets and the surface of enamel. 11 types of adhesive materials have been studied. 990 applications have been made using removed teeth, followed by a randomised creation of 11 groups containing 90 samples each. The threshold values of the strength needed to break the brackets off were determined in torsional, shear and tension strength tests. A comparison between tensometric and planimetric methods was made by means based on ARI index. Resistance was highest for torsional stress, weaker for shear stress and the weakest for tension stress. A correlation was found between tensometric results. The study attempted to systematise the methodology of direct tests.
16
PL
W artykule przedstawiono procedurę modelowania kości promieniowej, łokciowej i ramiennej człowieka. Zaprezentowano metodę przejścia z obiektu rzeczywistego do cyfrowego modelu bryłowego. Zastosowano metody inżynierii odwrotnej, to jest skanowanie współrzędnościowym ramieniem pomiarowym wyposażonym w głowice skanujące, oraz program CATIA w celu obróbki zeskanowanego modelu i nadania mu odpowiednich własności.
EN
The paper presents a procedure of modeling of the radial bone humerus bone and ulna bone of human arm. The article describes the problem of the transition from real to digital model. The subject of the research are the human forearm and arm bones, the radius, the ulna and the humerus. It was decided to create a digital model through reverse engineering techniques, using the coordinate arm equipped with set of markers for measuring geometrics, a file containing the point cloud was received, which was later on processed to the solid object by successive operation in CATIA.
17
Content available remote Analiza pewnych cech dynamicznych modeli kości ramienia człowieka
PL
W artykule, korzystając z nowoczesnych pakietów informatycznych, podjęto próbę badania wybranych własności dynamicznych kości kończyny górnej człowieka poprzez budowę odpowiednich modeli metodą MES przy założonych warunkach brzegowych. Otrzymane wyniki numeryczne i analityczne dotyczące drgań własnych przedstawiono w formie tabeli.
EN
In this paper, using modern informatics packets, an attempt to study the chosen dynamic properties of human upper limb bones by building appropriate models using FEM with the assumed boundary conditions was applied. Obtained numerical results and analysis of vibrations are presented in tabular form.
PL
W artykule opisano nowy model przebudowy tkanki kostnej w kontakcie z implantem , w mechanizmie działania którego uwzględnione są jednoczesne zmiany struktury wewnętrznej kości, jak i zmiany jej kształtu. Zaprezentowano także wyniki analizy z zastosowaniem tego modelu na przykładzie segmentu ruchowego kręgosłupa z protezą krążka międzykręgowego.
EN
A new model of bone functional adaptation in the vicinity of the implant is described in the paper. The model takes into consideration simultaneous changes in the internal structure and shape of the bone. A practical implementation of the model to analyse a spinal motion segment with an artificial intervertebral disc is also presented.
EN
The paper presents linear, logarithmic and exponential regression tabecular bone indices, fractal dimensions and strength. The analysis of the above parameters was supported by determining non-parametric correlation coefficients: Spearman’s ń, gamma and Kendall’s ô. The principal components’ analysis (PCA) was also performed in order to reduce the number of indices describing the variance in the data set. The analysis showed the most independent indices: lacunarity (ëm, ëmin, ëmax), BMD, Conn.D., SMI, DA, ńA and age.
EN
The knowledge of the mechanical characteristics of bone structures is a prerequisite for theoretical, numerical, and experimental analyses describing the functioning of bone, which is a living organ. The description of the mechanical properties of bone tissue, such as conventional Young’s modulus or strength, will enable the assessment of the degree of tissue degeneration through a comparison of the material properties of the examined bones to the properties determined for physiologically normal bones. However, the mechanical parameters published by different research centres often differ from each other by up to several hundred percent. These discrepancies arise primarily from the differences in the research methodology applied, and thus from many additional factors having a direct impact on the values of the mechanical parameters obtained in experimental tests. Therefore, in order to standardize and improve the interpretation of the results of measurements, we should develop universal criteria for the measuring conditions and quantify the impact of the factors being related to sample and measurements on the values obtained. In this paper, the authors present the dependence of some factors, i.e. the site and direction of sample excision as well as the rate and type of loading, on the values of the mechanical parameters. Those values were determined in experimental tests and the additional correlation coefficients proposed enabled an easier comparison of the results obtained with the values presented in the literature.
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