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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.
71

Age Dependent Spatial Characteristics of Epileptiform Activity in Malformed Cortex

Bell, L. Andrew 12 December 2011 (has links)
Developmental cortical malformations are a major cause of intractable seizures. Determining the location and timing of susceptibility for epileptiform activity is critical to identifying what mechanisms contribute to epileptogenesis in any model. Using the freeze lesion rat model of polymicrogyria, we have identified, in lesioned cortex, these two aspects of epileptogenesis. Previous studies have demonstrated that epileptiform activity cannot be evoked prior to postnatal day (P) 12, but the malformed cortex is more susceptible to seizures as early as P10. An increase in excitatory afferents to the epileptogenic zone occurs before the onset of network epileptiform activity. Whether or not these afferents are a major contributor to the hyperexcitability of the malformed cortex can be investigated by determining if they specifically create a susceptibility for epileptiform activity. We have examined that here by measuring whether that timing coincides with an increased susceptibility for evoked and spontaneous epileptiform activity. We report that the malformed cortex is more susceptible to evoked epileptiform activity than control cortex as earlier as P7 and as late as P36. Further, we also find that the form of spontaneous epileptiform activity in malformed cortex is altered as early as P7. The timing of these early disruptions of cortical function found here suggests additional epileptogenic mechanisms exist prior to the reported increase in excitatory afferents at P10. Determining the location of the seizure initiation is an essential part of epilepsy research. Some patients with developmental cortical malformations have seizures initiated within the malformation, while others have seizures generated by the surrounding cortex. Previous data in the freeze lesion model of microgyria suggests that the timing of freeze lesion (from P0 to P1) can shift the epileptogenic focus from the malformation to the paramicrogyrial region (PMR). We report that both the timing of the freeze lesion and the survival age of the animal can alter the epileptogenic circuitry of the malformation and surrounding tissue. These findings provide new insight to the timeline of hyperexcitability in malformed cortex and will possibly lead to greater surgical success for patients with intractable epilepsy.
72

Immunohistochemical Study of Phenotypes of Dendritic Cells in Dental Pulps from Non-Carious and Carious Teeth

Harmon, Melissa A. 01 January 2007 (has links)
Mature dendritic cells (DCs) in inflamed tissues may promote inflammation but the status of DCs in pulpitis is not known. We hypothesized that DC maturation would correlate with carious lesion depth and that CD4+ cells would be found in association with mature DCs. Pulps were collected from teeth exhibiting: (I) no caries (n=9), (II) shallow dentinal caries (n=5), and (III) deep caries (n=9). Pulpal tissues were cryo-sectioned and positive cells were examined with immunohistochemistry, Mature DCs (CD83+) were almost exclusively restricted to pulps from deep caries. Furthermore, CD209+ DCs in deep caries were elevated over other groups and CD209+ cells about doubled the CD83+ cells suggesting that immature DCs had accumulated and were available for terminal maturation. CD4+ cells were found associated with both mature DCs and macrophages in pulps from deep caries suggesting that T cells may be a source of pro-inflammatory cytokines at this inflamed site. This document was created in Microsoft Word 2000.
73

Sledování aktivace vybraných svalových skupin u klientů s míšním poraněním / Monitoring the activation of selected muscle groups of clients with spinal cord injury

Krátký, Jakub January 2013 (has links)
KRATKY, Jakub. Monitoring the activation of selected muscle groups of clients with spinal cord injuries. Prague: Charles University, Faculty of Physical Education and Sport, 2013. 82 pages. Supervisor Doc. PaedDr. Karel Jelen, CSc The aim of this thesis is to monitor the activation of selected muscle groups (musculus deltoideus pars anterior, musculus deltoideus pars posterior, musculus triceps brachii caput laterale and musculus trapezius pars descendus) during double poling ergometry. Nine subjects with different spinal cord lesions volunteered to participate in the study. The surface electromyography is used to detect the musculus activation. The monitoring of four muscle groups is devided into three phases. Firstly, all the participants double-poled for one minute at moderate intensity according to the Borg scale. Each participant underwent a 10-minute intervention to correct the posture. In the last phase the volunteers exercised again for one minute at moderate intensity. The aim of the intervention is to decrease muscle activation of musculus deltoideus pars anterior and musculus trapezius pars descendus (muscles with a tendency to hypertonia during wheelchair propulsion and activity of daily living) and to increase muscle activation of musculus deltoideus pars posterior and musculus triceps...
74

Vizuální neurorehabilitace u pacientů s inkompletní míšní lézí / Visual neurorehabilitation by the incomplete spinal cord injury patients

Polák, Alois January 2017 (has links)
The aim of the study: The aim of this work is to find out the possibilities to influence the clinical state of the patients suffering with incomplete spinal cord lesion syndrome with the help of a therapeutic video played through a virtual reality helmet. Methods: The research was conducted with 22 probands (15 males and 7 females) aged between 27 and 76 years (the average age of 55±14 years) from the client of Rehabilitation Centre Kladruby. The probands were divided into two homogenised groups with the same number of members. The control group received a standard rehabilitation programme set by the Rehabilitation Centre. The research group followed the same plan but in addition to this, they were given helmets, and a video with virtual reality was played daily on the total of 30 occasions. The clinical state before conducting the research and after was evaluated using the standard test ASIA impairment scale where the observed transformation was the total of motoric points for the lower limbs. Initial and final examination was conducted by professional and highly trained staff at Kladruby, always doctors. The variance between the initial and the final examination results and the length of stay at the centre were used to set the relative transformation of the clinical state in comparison with the...
75

Quantificação imunofenotípica da polarização de macrófagos M1 e M2, em cistos radiculares de dentes decíduos e permanentes / Immunophenotypic quantification of M1 and M2 macrophages polarization in deciduous and permanent teeth radicular cysts

Bertasso, Amanda Silva 04 June 2018 (has links)
As lesões periapicais ocasionam destruição dos tecidos apicais e periapicais, por meio da exacerbação da resposta inflamatória e imune. O sistema imunológico é ativado e células são recrutadas para o local da lesão, incluindo os macrófagos, que podem ser polarizados em macrófagos M1 e M2.O presente estudo teve como objetivo quantificar macrófagos M1 e M2 em cistos periapicais de dentes decíduos e permanentes.Foram selecionados 15 casos de cistos periapicais de dentes decíduos e 10 cistos periapicais de dentes permanentes. Em todos os casos foi realizada análise histopatológica em HE, classificando o tipo e o grau do infiltrado inflamatório, por meio de escores. Além disso, foi realizada a quantificação dos marcadores CD68 (M1+, M2+) e CD163 (M1-,M2+) por meio da análise imunohistoquímica. Os resultados obtidos foram submetidos ao teste de Mann Whitney, com nível de significância de 5%.Embora tenham sido detectados macrófagos M1 e M2 tanto nas lesões dos dentes decíduos quanto dos permanentes, houve maior prevalência de macrófagos M2 (p<0,05). A comparação entre dentes decíduos e permanentes evidenciou maior quantificação de macrófagos M1 nas lesões dos dentes permanentes (p=0,002). Pôde-se concluir que os macrófagos M1 e M2 estão presentes nos cistos periapicais de dentes decíduos e permanentes, com maior quantidade de células M2. Além disso, os cistos periapicais dos dentes permanentes apresentaram maior quantidade de macrófagos M1, em comparação aos cistos dos dentes decíduos / The radicular lesion leads to the apical and periapical tissues destruction throughout an inflammatory and immune response. The immune system is activated and cells are recruited to the lesion site, which includes macrophages that can be polarized into M1 and M2 macrophages. The objective of this study was to quantify M1 and M2 macrophages in radicular cysts in permanent and deciduous teeth. In total, 15 radicular cysts cases in deciduous teeth and 10 in permanent teeth were selected. A histopathologic analysis in HE was performed, allowing the type and inflammatory infiltrates level classification in scores. In addition, the CD68 (M1+, M2+) and CD163 (M1-, M2+) markers were quantified through an immunohistochemistry analysis. The data acquired were submitted to a Mann Whitney test, with a 5% significance level. A higher prevalence of M2 macrophages (p<0.05) was observed, despite both M1 and M2 macrophages have been detected in the permanent and deciduous teeth lesions. The comparison between permanent and deciduous teeth presented a higher M1 macrophages quantity in permanent teeth lesions (p=0.002). In summary, the M1 and M2 macrophages are present in deciduous and permanent teeth radicular cysts, with a higher quantity of M2 cells. Moreover, the radicular cysts in permanent teeth have shown a higher M1 macrophages quantity when compared to cysts in deciduous teeth
76

Histological characterization of CT-identified osteoarthritic subchondral cysts and co-registration of CT with MRI

Fernan, John Edward 12 June 2019 (has links)
Osteoarthritis (OA) is a chronic disease that affects the joints, most commonly hands, hips, knees, feet, and spine (Litwic et al. 2013). The disease becomes more common with advanced age and is one of the most prevalent causes of disability in older populations. Currently there is no cure besides total joint replacement surgery, and there will be approximately 4 million Americans living with a hip replacement by the end of the next decade (Maradit Kremers et al. 2015). Osteoarthritis was classically characterized as a disease of progressive articular cartilage degradation, but the degeneration involves all tissues of the synovial joint including the periarticular muscles, joint capsule, synovium, ligaments, and subchondral and metaphyseal bone. The cause of pain in OA is not well understood, but it is known that bone marrow lesions (BMLs) identified in subchondral bone by MRI are an important determinant of pain (Felson et al. 2001; Kumar et al. 2013). Abnormal blood vessel growth may be responsible MRI signature of BMLs, and the commonality between pathways for angiogenesis and neurogenesis suggests this pathologic process may be the source of pain in OA. The objective of this study was to characterize the histologic nature of subchondral cysts identified by micro computed tomography (μCT) which had been registered with MRI images in which marrow lesions were identified. Femoral heads were collected from 10 patients (6 females and 4 females; age 29-80) who underwent total hip arthroplasty. All patients had MRIs performed within 6 months prior to surgery. The heads were fixed and scanned with μCT to identify cysts in the subchondral bone. A block of the femoral head containing the cyst of interest was resected and processed for histologic analysis. The sections were stained with either Safranin-O and Fast Green or hematoxylin and eosin to view the nature and composition of the tissue. A two-dimensional image from the μCT that corresponded to the histologic slice was matched with a coronal view from the MRI. The primary compressive group was reliably identified on μCT images and served as good indicator for orienting the CT to match with the MRI. The subchondral cysts that were matched to MRI all consisted of predominantly fibrous bone marrow and frequently had a large number of blood vessels within the tissue. Three of the eight cysts had cartilage intrusions that were located mostly within peripheral trabecular bone, though one cyst contained a nodule of cartilage surrounded by organized fibers with the texture of granulation tissue. The process of image registration was mostly performed manually, but the development of this process will contribute to a more refined, semi-automated process in the future. The ability to correlate the histopathology of CT-identified lesions with a signature patter on MRI will be an important tool for better characterizing the nature of BMLs and understanding the pathogenesis of OA.
77

Traitement des lésions osseuses par Ultrasons Focalisés de Haute Intensité : de la simulation aux applications cliniques / MR-guided high intensity focused ultrasound (MRgHIFU) ablation of bone lesions : from simulation to clinical application

Bing, Fabrice 22 November 2018 (has links)
Après un état de l’art sur l’ablation des lésions osseuses, les expérimentations HIFU sur l’os présentées ont montré un échauffement périosté plus étendu avec un tir profond. Les tirs sur le ciment, dont le coefficient α a été mesuré, reproduisent les mêmes courbes thermiques. Une simulation a été réalisée avec 2 valeurs de α (4.7 et 9.9 dB/cm) : l’échauffement est moins important avec α=4.7. La simulation confirme certains résultats de la thermo-IRM : une élévation thermique maximale au niveau du périoste (zone focale) avec le tir superficiel, un échauffement latéral plus marqué avec le tir profond et une tendance à l’inertie thermique. A partir d’une analyse rétrospective des cas traités par imagerie mini-invasive, l’ablation HIFU semble possible pour 50% des ostéomes ostéoïdes et 35.7% des métastases. 35.9% de cas supplémentaires auraient pu être traités par HIFU si une protection des structures sensibles ou une consolidation étaient réalisées. A 1 MHz, l’interférence des aiguilles avec les US n’était visible qu’avec les aiguilles 13G. Si les aiguilles 18 à 22G interfèrent peu avec les US, un écran acoustique pourrait se former à la suite d’injection de liquide. / After a “state of art” on bone lesions ablation techniques, bone experimentations presented showed that deep focalisation allows the best lateral periosteal heating. On cement, from which the coefficient α was measured, the same thermic curves were observed. A simulation was done with two values of α (4.7 et 9.9 dB/cm). A higher heating at the periosteal focal point with superficial focalisation and a higher periosteal lateral heating with deep focalisation with a thermic inertia, were confirmed with simulation. Heating was higher with the high α value. A retrospective analysis of the bone lesions treated with minimally invasive treatment showed that 50% of osteoid osteomas and 35.7% of metastases were classified as suitable with MRgHIFU alone. 35.9% additional cases may have been treated with dissection or consolidation. At 1 MHz, US distortion due to the presence of needles in the US cone was observed only with the 13-gauge needle. However, if 18 to 22G needles may induce few distortion, an acoustic barrier may appear if the liquid injected flows in front of the US.
78

Estudo in vitro da influência da tensão na formação de lesões cervicais não cariosas / In vitro study of the influence of the tension in the formation of non-carious cervical lesions

Leal, Noélia Maria de Sousa 24 October 2013 (has links)
Embora se aceite que as lesões cervicais não cariosas tenham uma etiologia multifatorial, as contribuições relativas dos vários agentes etiológicos permanecem obscuras. O presente estudo propõe um modelo que simula a formação de lesões não cariosas em laboratório e estuda a influência específica de cada tipo de tensão no dano provocado ao esmalte e/ou à dentina. A face vestibular de incisivos bovinos foi cortada em forma de palito com 18 mm x 3 mm x 3 mm. Cada palito recebeu um entalhe na região cervical da parede voltada para a polpa, com o objetivo de direcionar a concentração de tensões para a junção esmalte-dentina. Os corpos de prova (n=108) protegidos com verniz ácido resistente, exceto numa faixa de 1,5 x 18 mm da superfície vestibular, foram divididos em dois grupos, um imerso em solução de ácido acético pH 4,5 e o outro imerso em água destilada. Cada grupo foi dividido em três subgrupos (n=18), dos quais, dois deles sofreram carregamento estático de 800gf em dobramento, um para provocar tração e outro para compressão na região da junção esmalte-cemento, e o terceiro não foi submetido a carregamento. Após 72h de ensaio os palitos foram lavados, desidratados e embebidos em resina acrílica. Em cada grupo de 18 espécimes, 06 foram cortados no sentido longitudinal e 12 no sentido transversal do palito, obtendo-se lamelas de 0,05 mm. As lamelas foram fotografadas em microscópio de luz, e foi medida a profundidade de perda e/ou desmineralização de dentina e esmalte. Os dados obtidos foram submetidos à análise de variância ANOVA, seguida pelo teste de Tukey com 5% de significância. Para comparações entre diferentes regiões do mesmo corpo de prova, foi utilizado o teste t pareado. Foi avaliada também a ocorrência de trincas e fraturas. Não foram encontrados danos nas lamelas dos palitos imersos em água destilada. Nos espécimes seccionados transversalmente a profundidade de desmineralização do esmalte sob tração foi de 158±18m, significativamente maior que a dos demais grupos (138±21m para sem carga e 129±16m para compressão). A profundidade de desmineralização e perda de dentina nos palitos submetidos à tração foi 186±23m, seguidos de 160±20m nos palitos sem carga e 140±27m nos palitos sob compressão. Nos cortes longitudinais foram realizadas medidas da profundidade de desmineralização do esmalte em três pontos: na junção esmalte-dentina (E1), a 3,5 mm (E2) e a 7,0 mm (E3) desta junção. A profundidade de desmineralização do esmalte nos espécimes sob tração foi significativamente maior na região cervical (E1) que nas demais regiões. Para os corpos de prova que sofreram compressão, as regiões E1 e E2 não apresentaram diferença significativa entre si, porém a região E3 teve desmineralização significantemente menor às outras. Nos corpos de prova sem tensão só houve diferença significativa entre os dois extremos (E1 e E3). Foram observadas trincas e fraturas no esmalte cervical apenas nos espécimes submetidos à tração. Parece lícito concluir que a tensão influi na ação do ácido sobre os tecidos dentários, sendo que a tração aumenta significativamente os danos e a compressão tende a reduzi-los. / Although it is accepted that non-carious cervical lesions have a multifactorial etiology, the relative contributions of several etiological agents remain unclear. This study proposes a model which simulates the formation of non-carious lesions in laboratory and studies the specific influence of each kind of tension in the damage caused to the enamel and/or the dentin. The buccal surface of bovine incisor was cut in the stick form measuring 18mm x 3mm x 3mm. Each stick received a groove in the cervical region of the wall facing the pulp aiming to guide the tension concentration to the dentin-enamel junction. The specimens (n=108) protected with resistant acid varnish, except in a 1.5mm x 18mm labial surface range, were divided into two groups, one immersed in acetic acid solution pH 4.5 and the other in distilled water. Each group was divided into three subgroups (n = 18), in which, two of them suffered 800gf static load on folding, one for tensile and the other for compression in the enamel-cement junction region, and the third did not suffer loading. 72h after the trial, the sticks were washed, dehydrated and embedded in acrylic resin. In each group of 18 specimens, 06 were cut in the longitudinal direction and 12 in the transversal one of the stick, getting 0.05mm lamellae. The lamellae were photographed in light microscope, and the depth of loss and/or demineralization of enamel and dentin was measured. Te data were analyzed by ANOVA variance, followed by the Tukey test with 5% significance. For comparisons between different regions of the same specimen, the paired t test was used. It was also evaluated the occurrence of cracks and fractures. No damages were found in the lamellae sticks immersed in distilled water. In specimens cut transversely, the depth of enamel demineralization under tensile was 158±18m, significantly higher than the other groups (138±21m for unloaded and 129±16m for compression). The depth of demineralization and dentin loss in sticks submitted for tensile was 186±23m, followed by 160±20m for the unloaded sticks and 140±27m for the sticks under compression. In the longitudinal cut, measures of the enamel demineralization depth were made in three points: the enamel-dentin junction (E1), 3.5 mm (E2) and 7.0 mm (E3) of this junction. The enamel demineralization depth in specimens under tensile was significantly higher in the cervical region (E1) than in other regions. For the specimens that suffered compression, the regions E1 and E2 did not show significant difference between themselves, but the E3 region showed demineralization significantly lower than the others. In specimens without tension, there was only significant difference between the two extremes (E1 and E3). Cracks and fractures in the cervical enamel were observed specimens only in the specimens under tensile. It seems reasonable to conclude that tension influences in the acid action on the dental tissues, and that tensile increases significantly the damage and compression tends to reduce them.
79

Índice de qualidade de vida de Ferrans & Powers - versão feridas: estudo da responsividade / Ferrans & Powers Quality of Life Index Wound Version: a study about responsiveness

Oliveira, Alcicléa dos Santos 28 June 2012 (has links)
O pequeno número de pesquisas sobre os instrumentos do Índice de Qualidade de Vida de Ferrans & Powers (IQVFP) que tenham estado a propriedade psicométrica de responsividade, bem como o fato de que o instrumento Índice de Qualidade de Vida de Ferrans & PowersVersão Feridas (IQVFP-VF) foi testado, em regra, apenas quanto a sua confiabilidade e validade, incentivou a realização deste estudo que, para continuar o processo de validação deste instrumento, objetivou analisar a responsividade do IQVFP-VF em pacientes com feridas crônicas. O estudo é metodológico, prospectivo, observacional, com abordagem quantitativa. Foi realizado com 39 pacientes que possuíam feridas crônicas (atendidos em dois ambulatórios específicos para o tratamento de feridas) por meio de três avaliações utilizando o questionário IQVFP-VF (no início do estudo, 30 e 60 dias após o início). O IQVFP-VF é composto por 35 itens, divididos em quatro domínios: saúde e funcionamento (SF), sócio-econômico (SE), psicológico/espiritual (PE) e família (Fa). Analisou-se a responsividade por meio de métodos baseados na distribuição dos dados, utilizando o tamanho do efeito (TE), e também métodos baseados em âncoras por meio da avaliação global de mudança, intensidade da dor e a cicatrização de feridas. Os resultados mostram que a média dos escores total do IQVFP-VF foi de 21,3; 23,1 e 24,2 nas três avaliações, respectivamente. Comprovou-se a responsividade do IQVFP-VF por meio do TE ao se detectar mudanças pequenas em 30 dias de tratamento. Isso foi ratificado no período de 60 dias com resultados ainda melhores, com valores do tamanho do efeito de 0,86 para o escore total; 1,01 no domínio SF; e 0,66 para o domínio SE, com p-valor <0,001 para todos os referidos escores. A diferença minimamente importante (MID) obtida para as âncoras no QV total foi de 2,0 para a avaliação global da mudança; 2,0 para intensidade da dor; e 2,4 para a taxa de cicatrização de feridas. Concluindo, o estudo mostrou que o instrumento IQVFP-VF mostrou-se responsivo, sendo capaz de detectar mudanças ao longo do tempo em pacientes com feridas crônicas. / The small number of research about for Ferrans & Powers Quality of Life Index (FPQLI) that have been psychometric property of responsiveness, as well as the fact that the Wound Version (FPQLI-WV) was tested only regarding its reliability and validity prompted our study which, in order to continue the validation process, aimed at analyzing responsiveness of this instrument in patients with chronic wounds. This is a methodological prospective observational quantitative study. Was conducted with 39 patients with chronic wounds undergoing treatment at two outpatient services dedicated to wound treatment including three assessments using FPQLI-WV (at enrollment, 30 days and 60 days later). The FPQLI-WV consists of 35 items distributed into 4 domains: health and functioning (HF), socio-economic (SE), psychological/spiritual (PS) and family (F). Responsiveness was studied through data distribution methods, using effect size and also anchor-based methods, using global assessment of change, intensity of pain and wound healing. Results showed that mean total scores of FPQLI-WV in the three assessments were 21.2, 23.1 and 24.2, respectively . Regarding responsiveness, the small changes to be detected 30 days of treatment. This was ratified in 60 days with even better results, with effect size of 0.86 for total score and 1.01 in the HF domain and 0.66 for SE domain, with p value <0.001 for all these scores. The minimally important difference (MID) obtained for the anchors in total quality of life score (QOL) was 2.0, for global assessment of change; 2.0, for pain and for wound healing 2.4. In conclusion, the study showed that FPQLI-WV is responsive and able to detect change along time in patients with chronic wounds.
80

Avaliação do processo de desenvolvimento de desmineralização em esmalte dental humano utilizando a técnica de tomografia por coerência óptica / Human dental enamel demineralization process assessment using the optical coherence tomography technique

Cara, Ana Claudia Ballet de 20 August 2012 (has links)
A detecção de lesões cariosas nos estágios iniciais possibilita a escolha de tratamentos baseados na preservação da estrutura dental. Dessa forma, a utilização de exames capazes de diagnosticar precocemente essas lesões, como a Tomografia por Coerência Óptica (OCT Optical Coherence Tomography) é adequada. Assim, o objetivo do trabalho foi avaliar a capacidade da OCT em quantificar os estágios de desmineralização do esmalte durante o desenvolvimento de lesões simuladas de cárie, tendo como padrão de referência o teste de microdureza seccional. Foram utilizados 53 dentes terceiros molares hígidos, os quais tiveram as coroas seccionadas para obtenção de 210 amostras. Para avaliar as possíveis alterações sofridas por cada amostra, essas foram examinadas através da técnica de OCT no início do experimento e novamente examinadas após o término do período de ciclagem estabelecido para cada grupo, utilizando os coeficientes de atenuação óptica total e o cálculo de área em gráficos de intensidade de sinal de OCT, como parâmetros de análise. Posteriormente, as amostras foram submetidas a testes de microdureza seccional. A diferença entre os coeficientes de atenuação óptica obtidos antes e depois da ciclagem de pH apresentou elevado grau de correlação com os resultados de microdureza seccional. Por meio da análise das áreas provenientes de gráficos de intensidade de sinal de OCT e microdureza Knoop, ambos em função da profundidade, foi observada relação de linearidade entre os resultados e elevada correlação entre as técnicas avaliadas (&rho; = 0,99). De acordo com os resultados, a técnica de OCT foi capaz de detectar diferentes graus de desmineralização do esmalte dental humano em lesões simuladas de cárie. / The detection of carious lesions in early stages enables treatment choose based on dental structure preservation. This way, the utilization of exams capable of early diagnosis of these lesions, like OCT (Optical Coherence Tomography), is appropriate. Therefore, the objective of this work was to assess the capability of OCT in quantifying the enamel demineralization stages during the development of simulated caries lesions, having as reference standard the sectional microhardness test. There were used 53 sound third molars, which had their crowns sectioned to obtain 210 samples. To assess possible changes in each sample, these were examined by the OCT technique in the beginning of the experiment and again in the end of the cycling period established to each group, using the total optical attenuation coefficient and the area calculations using OCT signal intensity as analysis parameters. After that, the samples were submitted to sectional microhardness test. The difference between optical attenuation coefficients taken before and after the pH cycling, showed a high level of correlation with the microhardness results. Through areas analysis of OCT signal intensity and Knoop microhardness against depth, it was observed linearity relation between results and high correlation among assessed techniques (&rho;=0,99). According to the results, the OCT technique was capable of detecting different degrees of demineralization of the human enamel in carious simulated lesions.

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