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Perfil microbiológico e imunológico do paciente com periodontite
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A periodontite é uma doença inflamatória crónica, que se caracteriza pela presença de um intenso infiltrado inflamatório associado a perda óssea alveolar irreversível e a destruição do tecido conjuntivo. Representa a causa mais prevalente de perda de dentes em humanos. A patogénese da periodontite relaciona-se com a interacção estabelecida entre a microbiota subgengival e a resposta imune do hospedeiro. A transição saúde- doença é acompanhada por alterações na flora predominante. Nos casos de doença, a flora microbiana é essencialmente constituída por microrganismos Gram-negativos anaeróbios, em detrimento de microrganismos facultativos Gram-positivos, comuns em saúde. Apesar da enorme variedade de bactérias existentes na cavidade oral, apenas um número reduzido está envolvido no desenvolvimento da periodontite. Os principais microrganismos associados a lesões periodontais destrutivas são Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, pertencentes ao complexo vermelho, Prevotella intermedia e Aggregatibacter actinomycetemcomitans. A presença destes patogéneos desencadeia uma resposta imune inata e adaptativa, com o intuito de promover a sua eliminação. No paciente com periodontite existem alterações nos mecanismos de defesa, que permitem o desenvolvimento da doença e influenciam a sua severidade. A regulação génetica da resposta imune determina a existência de pacientes com diferentes capacidades de desenvolver respostas eficazes e protectoras contra as bactérias patogénicas. A susceptibilidade à periodontite deve-se à incapacidade do sistema imune desenvolver uma resposta altamente específica para os antigénios bacterianos dominantes.
Periodontitis is a chronic inflammatory disease, characterized by the presence of an intense inflammatory infiltrate associated with irreversible bone loss and destruction of the periodontal connective tissue. It represents the most prevalent cause of tooth loss in humans. The pathogenesis of periodontitis is related to the interaction established between the subgingival microbiota and the subsequent host immune response. The health-illness transition is accompanied by changes in the predominant flora. In diseased situations, microbial flora consists mainly of Gram-negative anaerobes, while Gram-positive microorganisms are commonly found in healthy cases. Despite the enormous variety of bacteria in the oral cavity, only a small number is involved in the development of periodontitis. The main microorganisms associated with destructive periodontal lesions are Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, belonging to the red complex, Prevotella intermedia and Aggregatibacter actinomycetemcomitans. The presence of these pathogens triggers an innate and adaptive immune response, in order to promote their elimination. Patients with periodontitis present disorders in their defense mechanisms that allow the development of disease and influence its severity. The genetic regulation of the immune response determines that there are patients with different capacities to develop effective responses and protection against pathogenic bacteria. The susceptibility to periodontitis is due to the inability of the immune system to develop a highly specific response against to the dominant bacterial antigens.
Periodontitis is a chronic inflammatory disease, characterized by the presence of an intense inflammatory infiltrate associated with irreversible bone loss and destruction of the periodontal connective tissue. It represents the most prevalent cause of tooth loss in humans. The pathogenesis of periodontitis is related to the interaction established between the subgingival microbiota and the subsequent host immune response. The health-illness transition is accompanied by changes in the predominant flora. In diseased situations, microbial flora consists mainly of Gram-negative anaerobes, while Gram-positive microorganisms are commonly found in healthy cases. Despite the enormous variety of bacteria in the oral cavity, only a small number is involved in the development of periodontitis. The main microorganisms associated with destructive periodontal lesions are Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, belonging to the red complex, Prevotella intermedia and Aggregatibacter actinomycetemcomitans. The presence of these pathogens triggers an innate and adaptive immune response, in order to promote their elimination. Patients with periodontitis present disorders in their defense mechanisms that allow the development of disease and influence its severity. The genetic regulation of the immune response determines that there are patients with different capacities to develop effective responses and protection against pathogenic bacteria. The susceptibility to periodontitis is due to the inability of the immune system to develop a highly specific response against to the dominant bacterial antigens.
Descrição
Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2011
Palavras-chave
Periodontologia Teses de mestrado - 2011