Thesis (M.S.D.)--Indiana University School of Dentistry, 2009. / Title from PDF t.p. (viewed Aug. 11, 2009) Advisors: Mychel Vail, Chair of the Research Committee, Susan Zunt, Ted Parks, Kenneth Sponik, Joseph Legan. Curriculum vitae. Includes abstract. Includes bibliographical references (leaves 103-119).

Made available in DSpace on 2014-06-11T19:24:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-02-07Bitstream added on 2014-06-13T20:47:07Z : No. of bitstreams: 1 borges_mag_me_arafo.pdf: 2407696 bytes, checksum: a7e81553772fd5e27e2af158198bf735 (MD5) / O objetivo deste trabalho foi avaliar comparativamente três meios de diagnóstico em endodontia utilizando a radiografia convencional, radiografia digital indireta e a tomografia computadorizada helicoidal. Para tanto foram selecionados 20 casos clínicos onde já haviam realizado os exames radiográficos, tomográficos e exame macroscópico para a comprovação clínica. Foram selecionados três examinadores para a avaliação das radiografias convencionais e digitais com a finalidade de elaborarem um diagnóstico clínico. Após essa elaboração o diagnóstico somado ao diagnóstico tomográfico estes foi confrontado com o macroscópico para a comparação. A conclusão obtida foi em ordem decrescente, tomografia computadorizada helicoidal, radiografia digital e por último a radiografia convencional. / The objective of this work was to evaluate comparativily three ways of diagnosis in endodontia using the conventional x-ray, indirect digital x-ray and the computerized cat scan helical. For 20 cases had been in such a way selected clinical where already they had carried through the radiográficos, tomographic examinations and macrocospic examination for the clinical evidence. Three examiners for the evaluation of the conventional and digital x-rays with the purpose had been selected to elaborate a clinical diagnosis. After this elaboration the diagnosis added to the tomographic diagnosis these was collated with the macrocospic one for the matching. The gotten conclusion was orderly decreasing, computerized cat scan helical, digital x-ray and finally the conventional x-ray.

Resumo: O objetivo deste trabalho foi avaliar comparativamente três meios de diagnóstico em endodontia utilizando a radiografia convencional, radiografia digital indireta e a tomografia computadorizada helicoidal. Para tanto foram selecionados 20 casos clínicos onde já haviam realizado os exames radiográficos, tomográficos e exame macroscópico para a comprovação clínica. Foram selecionados três examinadores para a avaliação das radiografias convencionais e digitais com a finalidade de elaborarem um diagnóstico clínico. Após essa elaboração o diagnóstico somado ao diagnóstico tomográfico estes foi confrontado com o macroscópico para a comparação. A conclusão obtida foi em ordem decrescente, tomografia computadorizada helicoidal, radiografia digital e por último a radiografia convencional. / Abstract: The objective of this work was to evaluate comparativily three ways of diagnosis in endodontia using the conventional x-ray, indirect digital x-ray and the computerized cat scan helical. For 20 cases had been in such a way selected clinical where already they had carried through the radiográficos, tomographic examinations and macrocospic examination for the clinical evidence. Three examiners for the evaluation of the conventional and digital x-rays with the purpose had been selected to elaborate a clinical diagnosis. After this elaboration the diagnosis added to the tomographic diagnosis these was collated with the macrocospic one for the matching. The gotten conclusion was orderly decreasing, computerized cat scan helical, digital x-ray and finally the conventional x-ray. / Orientador: Renato de Toledo Leonardo / Coorientador: Idomeo Bonetti Filho / Banca: Fábio Luiz Camargo Villela Berbert / Banca: Celso Kenji Nishiyama / Mestre

Swedish Radiation Safety Authority has suggested guide-lines regarding information to individuals who undergo radiographic examinations. The guide-lines concerns medical care but patients in dental care can also be expected to have a wish to be informed about ionizing radiation. The main objective was to find out the patient’s perception of their knowledge about x-ray radiation and if they have a need to know more about x-rays. A questionnaire study was performed at two public dental clinics in Sweden during a twomonth period in the summer 2016. Patients ≥ 18 years old who gave their consent to participate were included in the study. Of all 429 participants 44 % declared an average knowledge about x-ray radiation and 37 % of all participants declared an inadequate knowledge. A total of 54 % had been informed about x-ray and its effects. School was the most common information source. Approximately 76 % had the perception that dental x-ray radiation is not harmful. 51 % declared the need to know more about x-ray. Approximately 52 % declared no knowledge about natural background radiation and 59 % declared it valuable to know more about dental x-ray in relation to natural background radiation. The participants showed mixed opinion and perception about x-ray radiation. A majority of patients want to know more about x-ray radiation. The study did not identify any particular group(s) needing more information about x-ray radiation than what is included in the justification of the radiographic examination.

No estudo de imagens radiográcas, os parâmetros relacionados ao contraste objeto, SC, razão sinal ruído, SNR, e dose, estão vinculados à forma do espectro de raios X utilizado e seu conhecimento permite predizer e otimizar a qualidade da imagem. Neste trabalho foi desenvolvida uma metodologia que permite obter o espectro de tubos de raios X odontológicos de uso clínico de forma indireta. Esta metodologia é baseada na aplicação de um modelo matemático que utiliza a transformada inversa de Laplace da curva de transmissão do feixe para gerar dados sobre a distribuição espectral do mesmo. Com o auxílio de uma câmara de ionização e ltros alumínio de alta pureza, foram levantadas as curvas de transmissão de 8 tubos de raios X disponíveis comercialmente. Para a validação do método foi realizada a espectrometria direta com detector de telureto de cádmio (CdTe), cuja resposta foi determinada por simulação Monte Carlo (MC). A partir reconstrução espectral obtida, foram realizados estudos sobre os parâmetros de qualidade de imagem SNR, contraste objeto, SC, KERMA na entrada da pele. O desempenho dos tubos foi avaliado com base na relação entre SNR e KERMA na entrada da pele. Os resultados mostram que é possível determinar a distribuição espectral de tubos de raios X odontológicos com base no método proposto. A relação proposta entre SNR e KERMA na entrada da pele sugere que tubos com fótons de baixa energia possuem baixo rendimento. / In the study of radiographic images, the parameters related to the subject contrast, SC, signal to noise ratio, SNR, and dose, are linked to the shape of the X-ray spectrum used and their knowledge allows to predict and optimize the image quality. In this work we developed a methodology to obtain the spectrum of dental X-ray tubes of clinical usage in an indirety way. This methodology is based on application of a mathematical model that uses the inverse Laplace transform of the attenuation curve to generate data on the spectral distribution of the beam. With the aid of an ionization chamber and high purity aluminum lters, were raised the transmission curves of 8 X-ray tubes that are available commercially. The method validation was performed with direct spectrometry detector cadmium telluride (CdTe), whose response was determined by Monte Carlo simulation (MC). From reconstruction obtained spectral studies were carried out on the parameters of SNR image quality, contrast object, SC, KERMA entrance skin. The performance of the tubes was evaluated based on the relationship between SNR and KERMA entrance skin. The results show that it is possible to determine the spectral distribution of dental X-ray tubes based on the proposed method. The proposed relationship between SNR and KERMA entrance skin suggests that tubes with low energy photons have a low performance.

No estudo de imagens radiográcas, os parâmetros relacionados ao contraste objeto, SC, razão sinal ruído, SNR, e dose, estão vinculados à forma do espectro de raios X utilizado e seu conhecimento permite predizer e otimizar a qualidade da imagem. Neste trabalho foi desenvolvida uma metodologia que permite obter o espectro de tubos de raios X odontológicos de uso clínico de forma indireta. Esta metodologia é baseada na aplicação de um modelo matemático que utiliza a transformada inversa de Laplace da curva de transmissão do feixe para gerar dados sobre a distribuição espectral do mesmo. Com o auxílio de uma câmara de ionização e ltros alumínio de alta pureza, foram levantadas as curvas de transmissão de 8 tubos de raios X disponíveis comercialmente. Para a validação do método foi realizada a espectrometria direta com detector de telureto de cádmio (CdTe), cuja resposta foi determinada por simulação Monte Carlo (MC). A partir reconstrução espectral obtida, foram realizados estudos sobre os parâmetros de qualidade de imagem SNR, contraste objeto, SC, KERMA na entrada da pele. O desempenho dos tubos foi avaliado com base na relação entre SNR e KERMA na entrada da pele. Os resultados mostram que é possível determinar a distribuição espectral de tubos de raios X odontológicos com base no método proposto. A relação proposta entre SNR e KERMA na entrada da pele sugere que tubos com fótons de baixa energia possuem baixo rendimento. / In the study of radiographic images, the parameters related to the subject contrast, SC, signal to noise ratio, SNR, and dose, are linked to the shape of the X-ray spectrum used and their knowledge allows to predict and optimize the image quality. In this work we developed a methodology to obtain the spectrum of dental X-ray tubes of clinical usage in an indirety way. This methodology is based on application of a mathematical model that uses the inverse Laplace transform of the attenuation curve to generate data on the spectral distribution of the beam. With the aid of an ionization chamber and high purity aluminum lters, were raised the transmission curves of 8 X-ray tubes that are available commercially. The method validation was performed with direct spectrometry detector cadmium telluride (CdTe), whose response was determined by Monte Carlo simulation (MC). From reconstruction obtained spectral studies were carried out on the parameters of SNR image quality, contrast object, SC, KERMA entrance skin. The performance of the tubes was evaluated based on the relationship between SNR and KERMA entrance skin. The results show that it is possible to determine the spectral distribution of dental X-ray tubes based on the proposed method. The proposed relationship between SNR and KERMA entrance skin suggests that tubes with low energy photons have a low performance.

The topic of this thesis is the design of dental X-ray. User problems were identified based on the design and technical analysis for which solutions are presented in the work. The innovative shape and design solution shows a new approach to dental X-rays. The main benefit of the design is the solution to real ergonomic problems that can occur during the interaction of the operator or patient and the device. The design corresponds to current trends in the evolving design field of medical design.

Concrete is the most widely used construction material in the world. Given its relative availability, strength, economy, and versatility to fit various applications, the material has been incorporated in roadways, bridges, buildings, and a host of other infrastructure projects. Oftentimes, concrete will be exposed to several environmental conditions that ultimately affect its durability and lifespan. These conditions include repeated freezing and thawing, chloride intrusion, sulfate attack, alkali-silica reaction, and many others. Given the age and condition of American infrastructure, concrete structures throughout the country need repair or rehabilitation. Often this repair includes the removal of degraded or damaged concrete and the application of an overlay material. There are several factors affecting the bond performance of the newly formed substrate-repair concrete, such as surface roughness, overlay material, and substrate moisture condition. The work presented in this thesis is dedicated to understanding the effect of substrate moisture condition on the overlay transition zone (OTZ) of the substrate-repair concrete. The substrate moisture condition can significantly impact the microstructure characterization of the OTZ. If the substrate is too dry, then it may absorb water from the repair material, reducing the local water-to-cement (w/c) ratio in the OTZ. Conversely, if the substrate is too wet, then the w/c ratio of the OTZ will be locally increased. In both scenarios, the interfacial bond strength is expected to be modified due to the change in the local w/c ratio. To understand this effect, various test methods and degradation mechanisms were explored. Initially, substrate-repair concrete specimens were prepared utilizing three separate substrate moisture conditions: saturated surfaced dry (SSD), sub-saturated surface dry (Sub-SSD), and oven dry (OD). After allowing these samples to cure, the strength and ion penetration risk were evaluated. The bond strength of the samples was evaluated through flexural strength testing and fracture energy determined through the RILEM draft tests. The OTZ ion penetration risk was evaluated by conducting rapid chloride penetration test (RCPT) on samples prepared with the three substrate moisture conditions. Furthermore, to determine the effect of repeated freezing and thawing on the OTZ and flexural strength, additional samples were created with the three moisture conditions. After allowing these samples to cure, they were subjected to ASTM C666 and were tested to observe their flexural strength. Another important performance indicator of concrete elements is its resistance to chloride ion penetration and corrosion. Since many structural elements are designed with steel reinforcement, chloride ion penetration represents a critical parameter in projecting material performance, since chloride ions will accelerate the rate of steel corrosion. Oftentimes, a key element in projecting this performance is identifying the rate at which ions diffuse through the material. There remain many established techniques to identify this rate of diffusion and derive a chloride diffusion coefficient; however, many of them are either destructive or qualitative in nature. In recent years, transmission X-ray microscopy (TXM) has been employed to non-destructively track diffusion and develop diffusion coefficients. The work presented in this thesis surrounds the efforts of incorporating TXM experiments at Virginia Tech. This work initially utilized a SkyScan 1174 μCT, and additional work in this thesis presents the design and construction of a dental X-ray system based on the checking ion penetration (CHIP) design. This system can conduct TXM experiments utilizing a dental X-ray as the source. The research, design, and construction of the CHIP system is discussed in this thesis. Ultimately, the research in this thesis has not observed any significant relationship between substrate moisture condition and overlay bond strength. There does appear to be an increase in chloride ion resistance for drier substrates, suggesting that pre-wetting the surface increases penetrability of the interface. / Master of Science / Concrete is the most widely used construction material in the world. Given its relative availability, strength, economy, and versatility to fit various applications, the material has been incorporated in roadways, bridges, buildings, and a host of other infrastructure projects. Oftentimes, concrete will be exposed to several environmental conditions that ultimately affect its durability and lifespan. These conditions include repeated freezing and thawing, chloride intrusion, sulfate attack, alkali-silica reaction, and many others. These environmental conditions ultimately degrade the material by inducing cracks, exposing steel reinforcement, and spalling. When the concrete has experienced significant deterioration, repair and rehabilitation of the damaged section must be performed. Most often, this repair consists of the removal of damaged concrete and the application of an overlay material to prevent further deterioration. The topics discussed in this thesis evaluate the optimum substrate conditions prior to an overlay application and the implementation of techniques to evaluate deterioration mechanisms. There are several substrate conditions that will affect bonding with the overlay material, including surface roughness, moisture conditions, and overlay type. This paper focused on the moisture condition and what effect this had on bond strength and resistance to chloride intrusion. This effect was studied in laboratory conditions and under environmental conditions such as rapid freezing and thawing. Several different deterioration mechanisms may contribute to concrete degradation. The research presented in this thesis also aimed to evaluate chloride ion diffusion. To evaluate this mechanism, two systems were explored with the intent of conducting transmission X-ray microscopy (TXM). With TXM, chloride ion diffusion can be tracked to determine the rate at which ions diffuse through the concrete. The two systems explored were an X-ray computed tomography scanner and a dental X-ray system. Both systems can conduct TXM, and this paper presents the efforts dedicated to developing them for this technique at Virginia Tech. Ultimately, the research in this thesis has not observed any significant relationship between substrate moisture condition and overlay bond strength. There does appear to be an increase in chloride ion resistance for drier substrates, suggesting that pre-wetting the surface increases penetrability of the interface.