ÚMTMB-odbor biomechaniky

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    The influence of image processing of -CT images on mechanical behavior of mandibular trabecular bone structure using micro finite element method
    (Elsevier, 2023-01-13) Šustková, Apolena; Thomková, Barbora; Zikmund, Tomáš; Kaiser, Jozef; Joukal, Marek; Marcián, Petr
    Computational modeling plays an important role in assessment of biomaterial structures, living tissue and their mechanical properties. Microstructure investigation of bone tissue needs high-level computational models based on -CT images. A crucial factor when creating a computational model is image processing using tissue segmentation. The most common method for segmentation is thresholding. Threshold value can influence the geometry model and mechanical response in the bone tissue. One of the aims of the work is to determine and analyze the apparent mechanical behavior of mandibular trabecular bone structure based on different threshold value. Another aim of this study is to assess its influence on strain intensity from a local point of view, namely on one specific trabeculae. Fifty-four computational models including detailed trabecular structure of mandible were created based on -CT images. The thresholding was observed to have a significant effect on mechanical behavior of the trabecular bone structure.
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    Micro-CT, Mechanical, and Histological Examination of the Effect of Local Adjuvants on Porcine Cortical Bone Following Intralesional Curettage of Bone Tumors
    (Springer Nature, 2024-05-14) Apostolopoulos, Vasileios; Boháč, Petr; Marcián, Petr; Staniczková Zambo, Iva; Pazourek, Lukáš; Mahdal, Michal; Neradil, Jakub; Návrat, Tomáš; Tomáš, Tomáš
    Background and Objectives Curettage is the removal of a tumor from the bone while preserving the surrounding healthy cortical bone, and is associated with higher rates of local recurrence. To lower these rates, curettage should be combined with local adjuvants, although their use is associated with damage to nearby healthy bone. Objective The purpose of this analysis is to determine the effect of local adjuvants on cortical porcine bone by using micro-computed tomography (micro-CT) along with histological and mechanical examination. Methods Local adjuvants were applied to porcine specimens under defined conditions. To assess changes in bone mineral density (BMD), a micro-CT scan was used. The pixel gray values of the volume of interest (VOI) were evaluated per specimen and converted to BMD values. The Vickers hardness test was employed to assess bone hardness (HV). The depth of necrosis was measured histologically using hematoxylin and eosin-stained tissue sections. Results A noticeable change in BMD was observed on the argon beam coagulation (ABC) sample. Comparable hardness values were measured on samples following electrocautery and ABC, and lowering of bone hardness was obtained in the case of liquid nitrogen. Extensive induced depth of necrosis was registered in the specimen treated with liquid nitrogen. Conclusion This study determined the effect of local adjuvants on cortical bone by using micro-CT along with histological and mechanical examination. Phenolization and liquid nitrogen application caused a decrease in bone hardness. The bone density was affected in the range of single-digit percentage values. Liquid nitrogen induced extensive depth of necrosis with a wide variance of values.