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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

"Estudo comaparativo das densidades radiográficas de diferentes filmes periapicais obtidas por meio da análise computadorizada em valores de alumínio-equivalente" / Comparison of radiographic densities from different dental intraoral x-ray films by computed analysis into aluminium-equivalent values

Felipe Paes Varoli 02 July 2004 (has links)
RESUMO O objetivo deste estudo foi obter as densidades radiográficas de diferentes filmes periapicais por meio de um programa computadorizado que utiliza a imagem equivalente em alumínio (alumínio-equivalente). Avaliaram-se os filmes Agfa Dentus M2 “Comfort”, Kodak InSight, Kodak Ektaspeed Plus, Kodak Ultra-speed e Kodak D. Todos foram expostos aos raios X juntamente com um escalímetro de Alumínio, variando-se o tempo de exposição (0,1 a 1 segundo). Após a leitura das densidades radiográficas construiu-se um gráfico para compararmos as propriedades sensitométricas dos filmes. O filmes mais sensíveis foram o Agfa Dentus M2 “Comfort” e o Kodak InSight, e os menos sensíveis o Kodak Ultra-speed e o Kodak D. Os filmes Agfa Dentus M2 “Comfort” e Kodak InSight apresentaram os maiores contrastes. Os resultados obtidos por este método indicam que deve-se utilizar os filmes Agfa Dentus M2 “Comfort” e Kodak InSight para reduzir a dose de radiação recebida pelo paciente. / ABSTRACT The aim of this study was to obtain radiographic densities from different dental intraoral x-ray films through a software using aluminium-equivalent image. The densities had been measured in order to compare dental x-ray films in terms of speed, base plus fog, and contrast. Agfa Dentus M2 “Comfort”, Kodak InSight, Kodak Ektaspeed Plus, Kodak Ultra-speed and Kodak D-speed films were evaluated. All films were exposed together with aluminium wedge, at times ranging from 0,1-1 second. By plotting a graphic of density against exposure, sensitometric properties were compared. Agfa Dentus M2 “Comfort” and Kodak InSight films obtained the highest film speed; Kodak Ultra-speed and Kodak D-speed films exhibited the lowest sensitivity. Agfa Dentus M2 “Comfort” and Kodak InSight films had presented valuesm to contrast superior to other films. Therefore, Agfa Dentus M2 “Comfort” and Kodak InSight films must be recommended to minimize the radiation dose to the patient.
62

Estudo radiográfico retrospectivo das alterações do proventrículo em psitacídeos / Retrospective radiographic study of proventricular abnormalities among psittacines

Patricia Lima Praes 07 October 2013 (has links)
Este estudo retrospectivo revisa os achados radiográficos em exames simples e contrastados de 38 aves psittaciformes com alterações no proventrículo. Os dados foram obtidos do Serviço de Diagnóstico por imagem do departamento de cirurgia junto ao Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, durante o período de janeiro de 2004 a abril de 2012. A distribuição das alterações, assim como as suas respectivas espécies e idades, foram estudadas. O sexo das aves não foi considerado neste estudo. A espécie Amazona aestiva (papagaio-verdadeiro) alcançou a porcentagem mais elevada (44,8%) entre as diversas ordens, seguidos pelos Nymphicus hollandicus (Calopsita) (28,9%). Neste período de oito anos, os sintomas mais comuns observados na anamnese foram a \"apatia/prostração\" e \"anorexia/prostração\" (52,63% cada). Entre as suspeitas clínicas mais frequentes, a doença da dilatação do proventrículo (PDD) foi a mais citada (26,32%). O achado radiográfico mais frequentemente observado foi a \"dilatação do proventrículo por conteúdo de radiodensidade gás e líquido\" (34,21%). A medição do proventrículo foi um dado descrito em 34,84% dos laudos. Dentre as aves estudadas com alterações radiográficas em proventrículo, o exame radiográfico contrastado por sulfato de bário foi solicitado em 26,32% dos casos, onde o achado radiográfico mais comum foi a \"retenção do meio de contraste ou evolução lenta do mesmo\". Dentre os casos com suspeita clínica de PDD, os únicos nos quais foi possível obter confirmação foram aqueles em que foi solicitado o exame contrastado. Algumas aves também exibiram alterações radiográficas inespecíficas. A dilatação de proventrículo em si não é patognomônica para PDD, visto que esta pode vir de forma atípica e que há diversas outras doenças que causam alterações semelhantes. / This retrospective study examines radiographic findings of plain and contrastenhanced examinations of 38 psittacine birds presenting proventricular abnormalities. The data were obtained by the Image Diagnostic Service of the Veterinary Hospital of the School of Veterinary Medicine and Animal Science of the University of São Paulo between January 2004 and April 2012. The distribution of the abnormalities, as well as the birds species and ages, were also investigated. The birds sex was not taken into account. The highest percentage among the different orders (44.8%) was observed among specimens of Amazona aestiva (Blue-fronted Parrot), followed by Nymphicus hollandicus (Cockatiel) (28.9%). In the eight-year period of the study, the most common symptoms were \"apathy/weakness\" and \"anorexia/weakness\" (52.63% each.) Proventricular Dilatation Disease (PDD) was the most frequent clinical suspicion (26.32%.) The most commonly observed radiographic abnormality was a \"Proventricular dilatation caused by content of gas and water radiodensity\" (34.21%.) The measurements of the proventriculus were described in 34.84% of all reports. Among the birds studied with radiographic alterations in proventriculus, radiographic examination contrasted by barium sulfate was required in 26.32% of cases. The most common findings were \"retention or slow transit of the contrast agent\". The only cases with a clinical suspicion of PDD for which it was possible to obtain a confirmation were those for which a contrast-enhanced examination was ordered. Some birds also presented radiographic abnormalities of uncertain diagnosis. A proventricular dilatation in itself is not pathognomonic of PDD inasmuch as said disease may present in an atypical manner and several other diseases may cause similar abnormalities.
63

Detection of periimplant fenestration and dehiscence using CBCT - an in vitro study = Diagnóstico tomográfico de fenestração e deiscência peri-implantar - estudo in vitro / Diagnóstico tomográfico de fenestração e deiscência peri-implantar - estudo in vitro

Vaz, Sergio Lins de Azevedo, 1984- 22 August 2018 (has links)
Orientador: Francisco Haiter Neto / Tese (Doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T00:06:43Z (GMT). No. of bitstreams: 1 Vaz_SergioLinsdeAzevedo_D.pdf: 2097588 bytes, checksum: 48e378674d749eb9b8ea2a05042e21a4 (MD5) Previous issue date: 2013 / Resumo: O presente estudo se propôs a avaliar a influência do tamanho de voxel e giro de escaneamento na detecção tomográfica de fenestração e deiscência peri-implantar, além do uso de filtros de imagem na detecção da deiscência peri-implantar. Em fragmentos de costelas bovinas, foi criado defeitos que simulariam fenestração e deiscência peri-implantar após a instalação de 100 implantes de titânio. As imagens foram adquiridas no tomógrafo computadorizado de feixe cônico i-CAT Next Generation, empregando FOV de 8 x 8 cm e três protocolos: A- voxel de 0,2 mm, giro de escaneamento de 180°; B- voxel de 0,2 mm, giro de 360°; C- voxel de 0,12 mm, giro de 360°. Cinco filtros do programa XoranCat foram testados: Angio Sharpen High 5x5, Shadow, Sharpen 3×3, Sharpen Mild e Smooth. Três cirurgiões-dentistas radiologistas identificaram a presença ou ausência dos defeitos. Curvas ROC foram criadas e os valores de área sob a curva (Az) comparados utilizando a Análise de Variância (ANOVA), com teste post hoc de Bonferroni (alfa de 5%). O teste de McNemar foi utilizado para comparar imagens (originais e com filtros) versus padrão ouro, bem como imagens originais versus imagens com filtros. Os resultados mostraram diferenças estatisticamente significantes entre os valores de Az dos protocolos B e C em relação ao protocolo A (p < 0,01) para deiscência. Houve diferenças estatisticamente significantes (p < 0,01) entre as imagens originais e o filtro Shadow em relação ao padrão ouro, bem como entre todos os filtros testados em relação às imagens originais. Concluiu-se que os tamanhos de voxel testados não influenciaram no diagnóstico de ambos os defeitos, enquanto que o giro de escaneamento completo (360°) foi melhor para deiscência. Diante da maior dificuldade no diagnóstico tomográfico de deiscência peri-implantar, o uso dos filtros de imagem testados é aconselhado, com exceção do filtro Shadow / Abstract: This study set out an assessment of the effects of two voxel sizes and scan modes of cone-beam computed tomography (CBCT) in periimplant fenestration and dehiscence detection. It also aimed to investigate whether CBCT filters would enhance the diagnosis of periimplant dehiscence. One hundred titanium implants were placed in bovine ribs in which periimplant fenestration and dehiscence were simulated. The images were acquired using the i-CAT Next Generation CBCT unit, with a FOV of 8 x 8 cm and the following protocols: A- 0.2 mm voxel size half-scan (180°); B- 0.2 mm voxel size full-scan (360°); and C- 0.12 mm voxel size full-scan (360°). Five filters of the XoranCat software were tested: Angio Sharpen High 5x5, Shadow, Sharpen 3×3, Sharpen Mild and Smooth. Three oral radiologists performed a dynamic evaluation of the presence/absence of the defects and ROC curves were created. The values of the area under the curve (Az) were compared with ANOVA and Bonferroni post-hoc test. The significance level was adopted at 5%. The McNemar test was applied to perform two comparisons in order to identify disagreements. All the enhanced and the original images were compared with the gold-standard and the original images were compared to the enhanced ones. The protocol A had significantly lower Az values than those obtained with the protocols B and C (p < 0.01) for dehiscence. The original images and the Shadow filter were statistically different from the gold-standard (p < 0.01). All the enhanced images also had statistically significant differences from the original images (p < 0.01). In conclusion, the voxel sizes did not influence in periimplant fenestration and dehiscence detection but the full-scan (360°) performed better than the half-scan for dehiscence. The use of enhancement CBCT filters for dehiscence detection is advised, with the exception of the Shadow filter / Doutorado / Radiologia Odontologica / Doutor em Radiologia Odontológica
64

Utilização de proteinas derivadas da matriz do esmalte (EMDOGAIN) no tratamento de defeitos intra-osseos : estudo longitudinal clinico e radiografico

Villalpando, Karina Teixeira 02 March 2003 (has links)
Orientador: Sergio de Toledo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-03T10:55:36Z (GMT). No. of bitstreams: 1 Villalpando_KarinaTeixeira_D.pdf: 2781584 bytes, checksum: 258b6c60ba7d0ffa1c34543cb90f5de2 (MD5) Previous issue date: 2003 / Resumo: O objetivo do presente estudo foi comparar através de parâmetros clínicos e radiográficos o tratamento cirúrgico de defeitos periodontais intra-ósseos com ou sem a utilização de um gel composto por proteínas derivadas da matriz do esmalte (EMDOGAIN ¿MARCA REGISTRADA¿. Quinze pacientes, apresentando um total de 19 defeitos intra-ósseos interproximais compostos por 1 ou 2 paredes ósseas em dentes unirradiculares, foram divididos aleatoriamente nos grupos teste e controle. Os parâmetros clínicos foram avaliados através de guias de sondagem - stents, antes do procedimento cirúrgico (baseline), com 6 e 18 meses de pós-operatório, sendo eles: posição da margem gengival relativa (PMGR), nível de inserção clínica relativo (NICR) e profundidade de sondagem (PS). Medidas radiográficas lineares foram obtidas nos mesmos períodos de avaliação, através de radiografias padronizadas e digitais. Os dados foram analisados estatisticamente usando ANOVA e o teste de Tukey (p< 0,05). Os resultados clínicos mostraram que aos 18 meses de avaliação houve, em média, uma redução da profundidade de sondagem de 3,2 '+ ou -' 1,44mm e um ganho no nível de inserção de 1,4 '+ ou - ' 1,26mm para o grupo teste, enquanto que no grupo controle, o valor médio de redução da profundidade de sondagem foi de 2,7 :t 0,89mm e do ganho de inserção clínica foi de 1,2 '+ ou -' 0,78mm. Radiograficamente, houve um preenchimento ósseo médio de 1,64 '+ ou -' 1,69mm no grupo teste e de 0,71 '+ ou -' 1,90mm no grupo controle. Os dois tratamentos cirúrgicos melhoraram os parâmetros clínicos e radiográficos quando comparados ao baseline, mas a diferença encontrada entre os grupos não foi estatisticamente significante. Portanto, pode-se concluir que o tratamento cirúrgico convencional e regenerativo têm efeitos favoráveis na redução da profundidade de sondagem, no ganho clínico de inserção e no preenchimento ósseo radiográfico após 18 meses de avaliação. Um estudo envolvendo uma amostra de tamanho maior é necessário para confirmar essa equivalência estatística entre as duas modalidades de tratamento / Abstract: The aim of the present study was to compare the clinical and radiographical effects of the treatment of intrabony periodontal defects with or without the use of a gel composed of enamel matrix proteins derivative (EMDOGAIN 'TRADEMARK¿). Fifteen patients, exhibiting a total of 19 defects 1 and 2 wall intrabony defects on one-rooted teeth, were randomly divided into test and control groups. Prior to surgery (baseline), 6 and 18 months after it the following parameters were evaluated using oclusal stents: relative gingival recession (RGR), relative clinical attachment levei (RCAL) and probing depth (PD). Linear radiographic measurements were obtained at the same time during this period through standard digital radiographies. Data were statistically analyzed using ANOVA and Tukey's Studentized Range Test (p< 0,05). The clinical results demonstrated that after 18 months there was a reduction in probing depth of 3.2 : '+ or -' 1.44mm and a gain in the clinical attachment levei of 1.4 '+ or -' 1.26mm on average for the test group. As for the control group the reduction in the probing depth was of 2.7 '+ or -' 0.89mm and the gain in the clinical attachment levei was of 1.2 '+ or -' 0.78mm on average. Radiographically, there was an average bone filling of 1.64'+ or -' 1.69mm in the test group and 0.7 '+ or -' 1.9mm in the control group. The two treatments improved clinical parameters as compared to baseline, but the differences found between the groups were not statistically significant. Therefore, it may be concluded that both therapies have similar effects in promoting probing depth reduction, clinical attachment gain, and defect bone till in the 18th month post treatment. A study involving a larger sample size is necessary to statistically confirm the equivalence between the two treatment modalities / Doutorado / Periodontia / Doutor em Clínica Odontológica
65

The association of variations in hip and pelvic geometry with pregnancy-related sacroiliac joint pain based on a longitudinal analysis / 妊娠期仙腸関節痛と骨盤帯ジオメトリーの関連

Ji, Xiang 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第21703号 / 人健博第69号 / 新制||人健||5(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 山田 重人, 教授 古田 真里枝, 教授 万代 昌紀 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM
66

The role of antemortem images of diffuse idiopathic skeletal hyperostosis (DISH) in positive identification

Zamora, Alyssa C. 14 February 2022 (has links)
The present study aimed to test the accuracy of using diffuse idiopathic skeletal hyperostosis (DISH) to make positive identifications using the method of antemortem and postmortem radiographic comparison. An online survey was developed to evaluate whether DISH is a feature of the skeleton that can be used in radiographic image comparison. Three digital radiographic images from 51 individuals were gathered for use in this study: one image taken at a baseline date (Group A), one image taken within 2 years from baseline (Group B), and one image taken greater than 4.5 years from baseline (Group C). A total of 40 survey participants were tasked with comparing between a simulated “antemortem” image and a “postmortem” image from living patients and identifying which image pair represented the same individual at different time intervals. Information about survey participants’ field, degree, experience working with radiographs, and familiarity with DISH were also recorded. Accuracy, sensitivity, and specificity were measured. Series 1 compared Group A images to Group B images and resulted in an accuracy of 87.3%, sensitivity of 46.9%, and specificity of 94.3%. Series 2 compared Group A images to Group C images and resulted in an accuracy of 83.4%, sensitivity of 34.3%, and specificity of 95.8%. The study concluded that the characteristics of DISH did not prove reliable for making positive identifications but established that DISH could be used to narrow down potential matches.
67

Bismuth Nanoparticles as Medical X-ray Contrast Agents: Synthesis, Characterization and Applications

Brown, Anna Laura 02 December 2013 (has links)
Bismuth based nanomaterials have recently attracted attention as heavy element X-ray contrast agents because of the high atomic number and predicted biological compatibility of bismuth. Nanoparticle X-ray contrast agents may enable a number of novel medical imaging applications, including blood pool and site-directed imaging. However these hypothetical applications are hindered by lack of suitable synthetic methods for production of imaging agents. This dissertation describes synthesis of a novel class of bismuth nanoparticles that are aqueously stabilized using poly and monosaccharides. These particles are synthesized using highly biologically compatible reagents and are oxidatively stable in water and in moderately basic buffered solutions. Bismuth nanoparticles stabilized by the polysaccharide dextran have a large hydrodynamic radius and a relatively small bismuth nanocrystal core (4% bismuth by volume.) Glucose-capped particles have a much higher ratio of bismuth by volume (>60%), and experimental CT scans of these particle solutions demonstrate higher X-ray contrast versus a current clinically used radiocontrast agent. Additional syntheses of hydrophobic organoamine-capped bismuth nanoparticles by reduction of an iodobismuth cluster, and development of other X-ray contrast materials, such as a radiopaque surgical sponge marker and ink, using bismuth micoparticles produced by a top-down ball milling method, are also described.
68

Ability of 5th year Students to Detect Early Interproximal Caries

Muzan, Abdalla January 2021 (has links)
Magister Scientiae Dentium - MSc(Dent) / Objective: The objectives of this study were to evaluate the diagnostic capability of 5th year students using digital imaging, conventional bitewing radiographs (BW), printed film on paper and to compare the results with the observers’ experience level to detect early interproximal caries lesions on radiographs. To map the literature in regards to different diagnostic methods that students use globally in dental clinics by conducting a scoping review. Methods: A cross-sectional study was conducted with senior dental students (Reg No: BM 19/9/8). Three digital radiographs were shown individually to the students on a screen, 3 bitewing radiographs and 3 printed films on paper were passed on individually to all students with a questionnaire; with a viewing time of 2 mins per radiograph; thus 9 radiographs in total were viewed. A control group consisting of specialists from both the Restorative and Radiology Departments had finalized the answers prior to conducting the study regarding the presence/absence of caries and its depth on all 3 different radiographic images. The answers recorded by students were divided into 5 categories, R0: Intact surface, R1: Radiolucency in outer half of enamel, R2: Radiolucency in inner half of enamel, R3: Radiolucency in outer half of dentin, and R4: Radiolucency in inner half of dentin. A protocol specific for the objectives of this study was developed according to the criteria for a scoping reviews. Relevant databases (Pubmed, Scopus, Ebscohost, Science Direct, Wiley Online Library and Cochrane Library) were searched to identify evidence which was restricted to the English language for the period 2015–2021. Results: Comparison using an Anova test on the 3 different diagnostic methods showed that the type of method used affects the presence detection and size measuring accuracy, where the P-value confirms a significant difference. The Prisma flow diagram showed a result of the most common methods for diagnosing interproximal caries happen to be visual examination and bitewing radiography. Conclusions: Senior dental students have shown good accuracy in detecting the presence of interproximal caries. Although the accuracy in detecting the size of carious lesions was poor.
69

Variables Influencing Time Since Injury of Pediatric Healing Fractures; Radiographic Assessment and Implications for Child Physical Abuse

Messer, Diana Lynn January 2019 (has links)
No description available.
70

Dimensional Grain Orientation and Preliminary Radiographic Studies of the Sandstones from the Finger Lakes Stone Quarry

de Grijs, Jan Willem 05 1900 (has links)
Missing page 10. / <p> Interbedded turbidite sandstones and shales of the Sonyea Group are exposed in the Finger Lakes Stone Quarry near Ithaca, New York. In 28% of the samples studied the orientation of the grains was not significantly different from a uniform distribution. These distributions included some that were bimodal and some obtained from a bed showing cross-stratification. In 60% of the samples the grain orientations could be considered parallel to the flute marks. As the top of the massive interval was approached the grain orientation became increasingly aligned with the flute marks. A difference of 14° was found between the vector means of the flute and tool marks. </p> <p> Radiographs made of rock slabs cut from the samples used in grain orientation determinations frequently failed to show internal structures even though these were visible in the samples. A radiograph of one sample (02-08) showed cross-bedding, not visible in the sample or slab. The absence of internal structures in a radiograph do not exclude their being present. </p> / Thesis / Bachelor of Science (BSc)

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