Made available in DSpace on 2017-07-24T19:21:57Z (GMT). No. of bitstreams: 1 Patricio Runnacles.pdf: 1899405 bytes, checksum: f12074a5a86f43aa25ef7c17d1ba8e87 (MD5) Previous issue date: 2014-12-17 / Objective: This in vivo study evaluated the baseline pulp temperature in human intact upper premolars and the pulp temperature rise induced by light emitted by a high power polywave Light Emitting Diode (LED) light curing unit (LCU); also, the possible correlation between the change in temperature (ΔT) and the volume of the crown and the pulp chamber ex vivo. Material and methods: after approval of the local Ethics Committee was obtained (protocol #255,945), upper right and left first premolars requiring extraction for orthodontic reasons from 8 volunteers (n=15) received infiltrative and intraligamental anesthesia and were isolated using rubber dam. A small, occlusal preparation was made using high-speed hand piece, under constant air-water spray, until a minute pulp exposure was attained. The sterile probe from a wireless, NIST-traceable, temperature acquisition system (Temperature Data Acquisition - Thermes WFI, Physitemp) was inserted directly into the coronal pulp. Once the baseline pulp temperature was stable, the buccal surface was exposed to polywave light from a LED LCU (Bluephase 20i, Ivoclar Vivadent) using selected EMs: 10-s either in low (10-s/L) or High (10-s/H); 5-s-Turbo (5-s/T); and 60-s-High (60-s/H) intensities, allowing a 7-min span between each exposure. Peak PT values and PT increases from baseline (ΔT) after exposure were subjected to 1-Way, repeated measures ANOVAs, and Bonferroni's post-hoc tests (α=0.05). Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. the teeth were extracted according to treatment plan. The crown and pulp volumes were measured using micro-tomography scanner, and pulp chamber / crown volume ratio was determined. Afterwards, premolar buccal-lingual, cervico-occlusal, mesio-distal dimensions as well as between cusp distances were measured using a digital caliper. Results: consistent temperature below body temperature, resulting in an average core temperature of 35 ° C (+ 0.7 ° C) was found. All modes of activation of the LED promoted significant temperature rise in the pulp chamber. A positive correlation between energy density and thermal variation was observed. No correlation was observed between coronal volume, the pulp chamber with temperature changes. A significant negative correlation was noted between pulp temperature changes when 10-s/L was used and VL. / Objetivo: Este estudo in vivo avaliou a temperatura basal da polpa em pré-molares hígidos superiores em humanos e o aumento da temperatura induzida pela luz emitida por um fotopolimerizador à base de Diodo Emissor de Luz (LED) polywave de alta potência; além disso, a possível correlação entre a variação de temperatura (ΔT) e o volume da coroa e da câmara pulpar ex vivo. Material e métodos: após aprovação da Comissão de Ética da Universidade Estadual de Ponta Grossa (UEPG) (protocolo #255,945), pré-molares direito e esquerdo de 8 pacientes voluntários (n=15), que necessitavam de extrações por motivos ortodônticos, receberam anestesia infiltrativa e intraligamentar e isolamento absoluto. Um pequeno acesso oclusal com exposição pulpar foi realizado usando alta-rotação, sob spray de ar e água constante, até atingir uma mínima exposição da polpa. Inseriu-se uma sonda estéril de um termopar wireless (Temperature Data Acquisition - Thermes WFI, Physitemp) diretamente no interior da câmara pulpar. Após a estabilização da temperatura basal da polpa, a face vestibular foi exposta à luz de um fotopolimerizador LED polywave (Bluephase 20i, Ivoclar Vivadent), usando modos de exposição selecionados: 10s em baixa potência (10s/L), 10s em alta potência (10s/H), 5s em potência turbo (5s/T) e 60s em alta potência (60s/H), respeitando um intervalo de 7 min entre cada exposição. A temperatura pulpar foi registrada a cada 0,2 s. Os valores absolutos e a variação da temperatura pulpar após exposição foram submetidos a análise estatística fator único (ANOVA) com medidas repetidas seguida pelo teste de Bonferroni (α=0,05). A correlação entre as densidades de energia aplicadas e os valores das variações de aumento de temperatura foi estabelecida por uma análise de regressão linear. Após as exodontias realizadas de acordo com os planos de tratamento, os elementos dentários (n=11) foram armazenados em Timol 0,1% e as dimensões mésio-distal da face oclusal (MD), cérvico-oclusal (CO), e vestíbulo-lingual (VL) da coroa dos dentes foram medidas com um paquímetro digital. Os volumes coronário e da câmara pulpar foram determinados por meio de microtomografia computadorizada (μCT) dos espécimes. Resultados: foi encontrada uma temperatura basal média consistente abaixo da temperatura corporal, de 35°C (+ 0,7°C). Todos os modos de ativação do LED promoveram aumento significativo de temperatura na câmara pulpar. Foi observada uma correlação positiva entre densidade de energia e variação térmica. Não houve correlação dos volumes coronal e da câmara pulpar com as variações térmicas, mas foi encontrada uma correlação negativa entre a medida VL das coroas e o ΔT no modo de exposição 10s/L.

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Dissertation Abstract Abdominalaortic aneurysm (AAA) is a serious disease. Its prevalence is in the developed countries about 3%. As an aneurysm is considered a dilatation of all layers of a vessel wall over 3 cm. Majority of AAA are small and asymptomatic, and although the risk of rupture increases with the size of aneurysm sack, even the small aneurysms rupture. The rupture mortaliry ranges about 70 %. Surgical treatment is indicated in the asymptomatic patients in diameter of AAA over 5 cm. The average speed of growth of AAA is 0.3 cm per year, e.g. in the early diagnosed patients there is a several years interval for a pharmacolocical influencing of the progression of this disease. Knowledge of pathogenesis is essential for any targeted pharmacological treatment. Our prospective, non-randomised studies are based on the application of the stereological methods for the histopathological assessment of the AAA samples. The acquired data enable the statistical analysis, including the null hypothesis testing. In our study analyzing the histopathology of AAA aortae of 65 patients (65 walls and 55 thrombi) and 6 normal abdominal aortae from the organ donors we assessed the following parameters: the area fractions of collagen and elastin, and the length density of elastin in intima and media, the area...

Suite à l'allongement de la survie des patients atteints de la mucoviscidose (CF), des études ont montré la présence d'une perte osseuse chez les patients CF. Dans ce travail de thèse, une étude de l'évolution de la densité minérale osseuse chez des souris atteintes de mucoviscidose a été effectuée en utilisant un système de micro-tomodensitométrie X. Afin d'améliorer les précisions des mesure, deux méthodes de correction de deux phénomènes physiques ont été appliquées. La première méthode est une correction du durcissement de faisceau X et basée sur une segmentation de l'objet reconstruit après une première reconstruction et en utilisant des courbes d'atténuations précalculées. La deuxième méthode est une méthode de correction de la diffusion des rayons dans l'animal basée sur l'estimation des projections des diffusés en utilisant des noyaux de diffusion précalculées. Des améliorations au niveau de la qualité de l'image et les mesures de densité osseuses ont été obtenues. / Due to the increased survival of the patients with cystic fibrosis (CF), studies showed the presence of osteoporosis in CF patients. In this work, a follow-up study of the bone mineral density (BMD) formice with CF is done using a micro-CT system. In order to perform accurately the measurements, weapplied two correction methods aiming to reduce artifacts in CT images. The first correction method is abeam hardening correction technique based on a post-reconstruction procedure and usingpre-calculated linearization curves. The second correction method is a hybrid elimination approach of scatter radiations from acquisition projections and based on the use of pre-calculated scatter kernels,simulated analytically. Improvements have been shown concerning image quality (contrast, artifactsreduction) and BMD measurements.

The methodology of visualization of soft tissue is in biology and medicine a topic for many years. During this period there were approving many techniques how to achieve accurate and authentic image of the researched object or structure. X-ray computed tomography is very helpful to get this goal but is necessary to improve contrasting techniques as well as the techniques of image post-processing. This thesis deals with imaging soft tissue. Specifically, it focuses on mouse liver contrasting with the artificial resin Microfil. Thesis also describes image processing technique (thresholding and region growing) for the data of the measurement with the goal of the visualization of the sample in 3D.

The thesis presents computational simulation of compression test of a nickel foam and the 3D reconstruction of micro-CT images was utilized to generate the foam’s model of geometry. Explicit FEM is used to simulate compression test using software tool LS-DYNA and the stress–deformation curve is obtained together with deformed model’s mesh used for subsequent analysis. Sensitivity analyses were performed to configure the model and ensure best fit with values obtained during real-life experiment. The ANSYS Classic environment was then used to simulate tensile test of the foam compressed to various thicknesses. The tensile moduli in three mutually perpendicular directions of nickel foam were computed and the results were compared to experimental values as well. The results of tensile test simulation revealed considerable anisotropy of the foam’s elastic behavior. It can be said that the measured experimental data correspond very well with the elastic properties obtained from simulation up to certain level of compression. Analysis of the relationship between the element size and tensile moduli showed a significant difference between fine and coarse mesh. The optimal level of discretization and the overall model configuration ensuring high level of accuracy is proposed in this thesis.

The aim of this semestral thesis is to compare the possibilities of available micro-CT systems. Theoretic part of this thesis there deals with possibilities of staining soft tissues and embryos because of enhancement the contrast of micro-CT images. Here follows a description of sources X-ray and detectors of available micro-CT systems. In practice there was realized the staining of embryo in cooperation with Department of histology and embryology in Brno. Then followed a measuring on FSI in Brno, ČVUT in Prague and synchrotron Elettra in Italy. In semestral thesis are described of the thesis there are compared the micro-CT systems and results of measuring embryos by means of presented systems and results are compared.The best results were obtained on micro-CT in Brno, where X-ray tube and flat panel detector were used. This images were used for a segmentation of cartilage olfactory system by means of 3D region growing. From results they were created 3D models for comparison with a manually segmented model. A less accurate results were obtain with the semi-automatic segmentation but this method isn’t too time-consuming.

Diplomová práce se zabývá detektory rentgenového záření pro mikro-CT systémy. Teoretická část zahrnuje standartní typy rentgenových detektorů a požadavky na kvalitu obrazu pro výslednou 3D rekonstrukci. V závěru jsou popsány fyzikální parametry reálných detektorů a metody jejich měření a vyhodnocení.

Das Ziel der hier durchgeführten Studie war es, die Möglichkeiten der zerstörungsfreien Untersuchungsmethode, 3-D-Röntgenmikrotomographie, bei der Bewertung von Wurzelkanalfüllungen anhand der modifizierten lateralen Kondensation, der lateralen Kondensation und bei Thermafil zu untersuchen. Es sollte gezeigt werden, dass die einzelnen Bestandteile der Wurzelkanalfüllung zu differenzieren und im Anschluss auch zu quantifizieren sind. Die ersten 21 mit dieser zerstörungsfreien Methode untersuchten Proben wurden im Anschluss nochmals mit einer klassischen Untersuchungsmethode, der Lichtmikroskopie, beurteilt. Die hier erzielten Ergebnisse wurden bei einem Methodenvergleich mit den Ergebnissen der 3-D-Röntgenmikrotomographie verglichen und auf eine mögliche Korrelation überprüft. Ziel war es zu überprüfen, ob verschiedene Methoden zur Qualitätsprüfung von Wurzelkanalfüllungen als gleichwertig angenommen werden können. Im Rahmen dieser Untersuchung wurde eine neue modifizierte laterale Kondensation eingeführt, die hinsichtlich ihrer Qualität anhand der bereits genannten Parameter mit zwei bereits eingeführten Wurzelkanalfüllmethoden verglichen werden sollte. Die 3-D-Röntgenmikrotomographie ermöglichte eine selektive Darstellung der einzelnen Komponenten in 400 bis 750 Ebenen, welche ebenfalls quantifizierbar waren. Es wurden Füllgrade zwischen 71 % und 92 % erzielt. Das Thermafil-System schien den auf lateraler Kondensation basierenden Systemen bezüglich der bestimmten Volumen vereinzelt signifikant überlegen. Bei der lichtmikroskopischen Auswertung ergaben sich diesbezüglich ähnliche Ergebnisse. Die Farbstoffpenetrationstiefen zeigten weder tendenzielle noch signifikante Unterschiede zwischen den einzelnen Fülltechniken. Beim Vergleich der Methoden zur Bewertung der Obturation bezüglich der erhobenen Volumen konnte keine Korrelation nachgewiesen werden. Auch beim Vergleich der Farbstoffpenetrationstiefen und der bestimmten Volumen bei der 3-D-Röntgenmikrotomographie konnten keine Korrelationen ermittelt werden. Unter Berücksichtigung der Grenzen dieser Untersuchung lässt sich festhalten, dass die Methode der 3-D-Röntgenmikrotomographie zur Bewertung und zum Vergleich von Wurzelkanalfüllungen geeignet ist. Die Ergebnisse korrelieren jedoch nicht mit denen der Lichtmikroskopie.

The preclinical imaging method micro-CT (microtomography) allows the visualization and quantification of the structure of samples at a resolution of micrometers. Its' importance is increasing globally. In addition to several advantages (non-destructive, the possibility of direct 3D analysis, time efficiency, etc.), micro-CT also has some significant limitations (problematic validation of results, image artifacts, significant influence of image modifications, etc.). This thesis focuses on the application of micro-CT in the field of research and development of metallic and non-metallic materials promoting bone healing with their possible clinical applications. The first part addresses the limitations of micro-CT through several studies. A comparison of pore sizes in biomaterials utilizing scanning electron microscopy (SEM) and micro-CT was performed, and the complications of pore size evaluation were presented. SEM image analysis leads to significantly higher values than micro-CT (approximately three times), which allows for comparison of the studies using only one of these methods. Validation of micro-CT 3D analysis results based on calibration phantoms with complex structure, to date, is not possible. We therefore developed software generating phantom datasets of 3D objects with well-defined...