Publications by authors named "Ladislava Horáčková"

6 Publications

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On the limits of finite element models created from (micro)CT datasets and used in studies of bone-implant-related biomechanical problems.

J Mech Behav Biomed Mater 2021 05 18;117:104393. Epub 2021 Feb 18.

Department of Oral and Maxillofacial Surgery, Division for Regenerative Orofacial Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany; Fraunhofer Research Institution for Additive Manufacturing Technologies IAPT, Hamburg, Germany.

Patient-specific approach is gaining a wide popularity in computational simulations of biomechanical systems. Simulations (most often based on the finite element method) are to date routinely created using data from imaging devices such as computed tomography which makes the models seemingly very complex and sophisticated. However, using a computed tomography in finite element calculations does not necessarily enhance the quality or even credibility of the models as these depend on the quality of the input images. Low-resolution (medical-)CT datasets do not always offer detailed representation of trabecular bone in FE models and thus might lead to incorrect calculation of mechanical response to external loading. The effect of image resolution on mechanical simulations of bone-implant interaction has not been thoroughly studied yet. In this study, the effect of image resolution on the modeling procedure and resulting mechanical strains in bone was analyzed on the example of cranial implant. For this purpose, several finite element models of bone interacting with fixation-screws were generated using seven computed tomography datasets of a bone specimen but with different image resolutions (ranging from micro-CT resolution of 25 μm to medical-CT resolution of 1250 μm). The comparative analysis revealed that FE models created from images of low resolution (obtained from medical computed tomography) can produce biased results. There are two main reasons: 1. Medical computed tomography images do not allow generating models with complex trabecular architecture which leads to substituting of the intertrabecular pores with a fictitious mass; 2. Image gray value distribution can be distorted resulting in incorrect mechanical properties of the bone and thus in unrealistic or even completely fictitious mechanical strains. The biased results of calculated mechanical strains can lead to incorrect conclusion, especially when bone-implant interaction is investigated. The image resolution was observed not to significantly affect stresses in the fixation screw itself; however, selection of bone material representation might result in significantly different stresses in the screw.
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http://dx.doi.org/10.1016/j.jmbbm.2021.104393DOI Listing
May 2021

A very rare case of possible actinomycosis of the mandible from the Middle Ages.

Int J Paleopathol 2020 12 16;31:53-59. Epub 2020 Sep 16.

Laboratory of Biological and Molecular Anthropology, Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic. Electronic address:

Objective: Documented cases of actinomycosis in archaeological skeletons are very rare, especially from Central Europe. Our contribution will help facilitate the differential diagnosis of this disease for other paleopathologists.

Material: This paper describes a pathological finding of the skeleton of a 40-year-old male from a burial ground in Sady-Špitálky (Czech Republic) dated to the 10th-12th century.

Methods: The affected skeleton was evaluated as a probable case of actinomycosis on the basis of a detailed macroscopic, X-ray and histological examination. The osteolytic foci examined were compared with similar changes caused by tuberculosis, syphilis and mycoses.

Results: The character and location of the defect on the mandible is indicative of organ actinomycosis and is also reflected by the lytic lesion observed on a lumbar vertebra.

Conclusions: The described case can be considered one of the very rare paleopathological findings of possible actinomycosis in humans in Central Europe.

Significance: Good evidence of bone actinomycosis findings may be beneficial for further paleopathological and epidemiological studies, especially for research focused on the diachronic development of actinomycosis in Europe. In doing so, all available factors, such as hygiene habits, nutrition, social structure and overall health of the population that could be causally related to its origin, course and treatment, can be taken into account.

Limitations: The mandible of the studied individual was damaged, especially in the area affected by the lesion, so the paleopathological analysis was difficult to perform.

Suggestion For The Future Research: In future, actinomycosis in this skeleton may be confirmed by bio-molecular analysis.
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http://dx.doi.org/10.1016/j.ijpp.2020.09.001DOI Listing
December 2020

Micro finite element analysis of dental implants under different loading conditions.

Comput Biol Med 2018 05 17;96:157-165. Epub 2018 Mar 17.

Institute of Solid Mechanics, Mechatronics and Biomechanics, Faculty of Mechanical Engineering, Brno University of Technology, Brno, Czech Republic.

Osseointegration is paramount for the longevity of dental implants and is significantly influenced by biomechanical stimuli. The aim of the present study was to assess the micro-strain and displacement induced by loaded dental implants at different stages of osseointegration using finite element analysis (FEA). Computational models of two mandible segments with different trabecular densities were constructed using microCT data. Three different implant loading directions and two osseointegration stages were considered in the stress-strain analysis of the bone-implant assembly. The bony segments were analyzed using two approaches. The first approach was based on Mechanostat strain intervals and the second approach was based on tensile/compression yield strains. The results of this study revealed that bone surrounding dental implants is critically strained in cases when only a partial osseointegration is present and when an implant is loaded by buccolingual forces. In such cases, implants also encounter high stresses. Displacements of partially-osseointegrated implant are significantly larger than those of fully-osseointegrated implants. It can be concluded that the partial osseointegration is a potential risk in terms of implant longevity.
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http://dx.doi.org/10.1016/j.compbiomed.2018.03.012DOI Listing
May 2018

A brief history of tuberculosis in the Czech Lands.

Tuberculosis (Edinb) 2017 07 19;105:35-48. Epub 2017 Apr 19.

Division of Medical Anthropology, Department of Anatomy, Faculty of Medicine, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic. Electronic address:

Tuberculosis currently remains a serious medical problem, therefore increased attention is being paid to this disease. Paleopathological studies focused on the monitoring of morbid changes in skeletal remains of historical populations facilitate a detailed study of the development of this disease. They provide direct evidence of the existence of tuberculosis and its past forms. In addition to literary and iconographic sources, the present study is focused on recording the findings of bone tuberculosis in historical osteological sets from the Czech Lands and is the starting point for their detailed review. Approximately 76 cases of bone tuberculosis from the Czech Lands have been published and more or less reliably documented from 20 archeological sites dated back from the Eneolithic to the modern period.
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http://dx.doi.org/10.1016/j.tube.2017.04.006DOI Listing
July 2017

Tumors in the 18th and 19th centuries at Brno, Czech Republic.

Anthropol Anz 2013 ;70(4):385-405

Symptoms signs of benign and malignant tumors were observed during paleopathological analysis of skeletal remains from the city of Brno in the Czech Republic. Approximately 1,200 skeletons were examined from two Modern era archaeology sites: the Malá Nová ulice (Little New Street) cemetery and the cemetery of the Nemocnice Milosrdných bratrí (Merciful Brothers' Hospital). Osteomas, usually located on the flat bones of the cranial vault, were the most frequent skeletal pathology. Symptoms signs of malignant tumors were observed in three cases. In one case lytic foci caused by the metastases of a malignant tumor in the soft tissue was observed. Traces of myeloma multiplex were found in two individuals. Living conditions in that period, and possible carcinogenic environmental influences were assessed for the general population of Brno. This report contributes to a better understanding of the historical development of cancers and the clarification of possible causes for their modern increase of incidence.
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http://dx.doi.org/10.1127/0003-5548/2013/0343DOI Listing
April 2014

[Death in the early modern period and medical anthropology].

Sb Pr Filos Fak Brnenske Univ Rada Hist 2002 ;51(49):33-9

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March 2007