RESUMO
The aim of this study was to evaluate the microbial distribution in the root canal system after periapical lesion induction in dogs' teeth using different methods. Fifty-two root canals were assigned to 4 groups (n=13). Groups I and II: root canals were exposed to the oral cavity for 180 days; groups III and IV: root canals were exposed for 7 days and then the coronal openings were sealed for 53 days. The root apices of groups I and III were perforated, while those of groups II and IV remained intact. After the experimental periods, the animals were euthanized and the anatomic pieces containing the roots were processed and stained with the Brown & Brenn method to assess the presence and distribution of microorganisms. The incidence of microorganisms at different sites of the roots and periapical lesions was analyzed statistically by the chi-square test at 5% significance level. All groups presented microorganisms in the entire root canal system. A larger number of microorganisms was observed on the root canal walls, apical delta and dentinal tubules (p<0.05), followed by cementum and cemental resorption areas. In spite of the different periods of exposure to the oral environment, the methods used for induction of periapical periodontitis yielded similar distribution of microorganisms in the root canal system.
Assuntos
Bactérias/crescimento & desenvolvimento , Cavidade Pulpar/microbiologia , Periodontite Periapical/microbiologia , Animais , Corantes , Cemento Dentário/microbiologia , Cemento Dentário/ultraestrutura , Dentina/microbiologia , Dentina/ultraestrutura , Cães , Boca/microbiologia , Pulpectomia , Obturação do Canal Radicular , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Reabsorção da Raiz/microbiologia , Reabsorção da Raiz/patologia , Fatores de Tempo , Ápice Dentário/microbiologia , Ápice Dentário/cirurgia , Ápice Dentário/ultraestruturaRESUMO
The aim of this study was to evaluate the microbial distribution in the root canal system after periapical lesion induction in dogs' teeth using different methods. Fifty-two root canals were assigned to 4 groups (n=13). Groups I and II: root canals were exposed to the oral cavity for 180 days; groups III and IV: root canals were exposed for 7 days and then the coronal openings were sealed for 53 days. The root apices of groups I and III were perforated, while those of groups II and IV remained intact. After the experimental periods, the animals were euthanized and the anatomic pieces containing the roots were processed and stained with the Brown & Brenn method to assess the presence and distribution of microorganisms. The incidence of microorganisms at different sites of the roots and periapical lesions was analyzed statistically by the chi-square test at 5 percent significance level. All groups presented microorganisms in the entire root canal system. A larger number of microorganisms was observed on the root canal walls, apical delta and dentinal tubules (p<0.05), followed by cementum and cemental resorption areas. In spite of the different periods of exposure to the oral environment, the methods used for induction of periapical periodontitis yielded similar distribution of microorganisms in the root canal system.
O objetivo deste estudo foi avaliar a distribuição microbiana no sistema de canais radiculares após indução de lesões periapicais em dentes de cães por diferentes métodos. Cinqüenta e dois canais radiculares foram divididos em 4 grupos (n=13). Grupos I e II: canais radiculares foram expostos por 180 dias; grupos III e IV: canais radiculares foram expostos por 7 dias e então as aberturas coronárias foram seladas por 53 dias. Os ápices radiculares dos grupos I e III foram arrombados, enquanto os dos grupos II e IV foram mantidos intactos. Após os períodos experimentais, os animais foram mortos e as peças foram processadas e coradas pelo método de Brown e Brenn para avaliação da presença ou ausência e distribuição dos microrganismos. A incidência de microrganismos nas diferentes regiões das raízes e lesões periapicais foi analisada estatisticamente pelo Teste Qui-Quadrado em nível de 5 por cento de significância. Todos os grupos apresentaram microrganismos em todo o sistema de canais radiculares. Um maior número de microrganismos foi observado nas paredes do canal radicular, delta apical e túbulos dentinários, seguido pelo cemento e áreas de reabsorção cementária. Apesar de utilizar diferentes períodos de exposição dos canais radiculares ao meio bucal, os métodos usados para indução das lesões periapicais permitiram semelhante distribuição de microrganismos no sistema de canais radiculares (p>0,05).
Assuntos
Animais , Cães , Bactérias/crescimento & desenvolvimento , Cavidade Pulpar/microbiologia , Periodontite Periapical/microbiologia , Corantes , Cemento Dentário/microbiologia , Cemento Dentário/ultraestrutura , Dentina/microbiologia , Dentina/ultraestrutura , Boca/microbiologia , Pulpectomia , Obturação do Canal Radicular , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Reabsorção da Raiz/microbiologia , Reabsorção da Raiz/patologia , Fatores de Tempo , Ápice Dentário/microbiologia , Ápice Dentário/cirurgia , Ápice Dentário/ultraestruturaRESUMO
The aim of this study was to evaluate the presence of bacterial biofilm on the external surface of the root apex in teeth with pulp necrosis, with and without radiographically visible periapical lesions, and in teeth with a vital pulp. Twenty-one teeth were extracted, eight with pulp necrosis and periapical lesions, eight with pulp necrosis without radiographically visible periapical lesions, and five with a vital pulp. The roots were sectioned, and the root apexes (+/- 3 mm) were processed for scanning electron microscope evaluation. The surface of the apical root was evaluated for the presence of microorganisms, root resorption, and biofilm. There were no microorganisms on the apical root surface of either teeth with pulp vitality or with pulp necrosis with no radiographically visible periapical lesions. Microorganisms were always present in teeth with pulp necrosis and radiographically visible periapical lesions. These included cocci, bacilli, and filaments and the presence of an apical biofilm. Apical biofilm is clinically important because microbial biofilms are inherently resistant to antimicrobial agents and cannot be removed by biomechanical preparation alone. This may cause failure of endodontic treatment as a consequence of persistent infection.
Assuntos
Necrose da Polpa Dentária/microbiologia , Ápice Dentário/microbiologia , Biofilmes , Cemento Dentário/diagnóstico por imagem , Cemento Dentário/microbiologia , Necrose da Polpa Dentária/diagnóstico por imagem , Humanos , Microscopia Eletrônica de Varredura , Periodontite Periapical/microbiologia , Radiografia , Reabsorção da Raiz/diagnóstico por imagem , Reabsorção da Raiz/microbiologia , Ápice Dentário/diagnóstico por imagemRESUMO
The aim of this study was the radiographic evaluation of the apical and periapical region of dog teeth submitted to intracanal bacterial endotoxin (lipopolysaccharide, LPS), associated or not with calcium hydroxide. After removal of the pulp, 60 premolars were divided into four groups and were filled with bacterial endotoxin (group 1), bacterial endotoxin plus calcium hydroxide (group 2), saline solution (group 3), or periapical lesions were induced with no treatment (group 4), for a period of 30 days. Similar periapical lesions were observed in groups 1 and 4. The lamina dura was intact in groups 2 and 3. Bacterial endotoxin (LPS) caused radiographically visible periapical lesions, but when associated with calcium hydroxide, this endotoxin was detoxified.
Assuntos
Hidróxido de Cálcio/uso terapêutico , Endotoxinas/efeitos adversos , Escherichia coli , Lipopolissacarídeos/efeitos adversos , Tecido Periapical/diagnóstico por imagem , Materiais Restauradores do Canal Radicular/uso terapêutico , Ápice Dentário/diagnóstico por imagem , Animais , Membrana Basal/diagnóstico por imagem , Reabsorção Óssea/diagnóstico por imagem , Reabsorção Óssea/microbiologia , Cães , Endotoxinas/antagonistas & inibidores , Lipopolissacarídeos/antagonistas & inibidores , Doenças Periapicais/diagnóstico por imagem , Doenças Periapicais/microbiologia , Tecido Periapical/microbiologia , Ligamento Periodontal/diagnóstico por imagem , Radiografia , Reabsorção da Raiz/diagnóstico por imagem , Reabsorção da Raiz/microbiologia , Estatísticas não Paramétricas , Ápice Dentário/microbiologiaRESUMO
AIM: The purpose of this study was to examine the presence of bacteria on the apical root surfaces of untreated teeth associated with chronic periradicular lesions. METHODOLOGY: Twenty-seven extracted teeth with extensive carious lesions, radiolucent lesions of varying sizes and attached periradicular lesions after extraction, were selected for study. Following fixation, lesions were removed and the apical 5-mm portion of each root was sectioned. Root tips were dehydrated, sputter-coated with gold, and then examined for the occurrence of bacteria on the apical root surfaces using a scanning electron microscope. RESULTS: Bacterial cells were usually observed close to the apical foramen, but restricted to the root canal. Morphologically, these bacteria consisted of cocci and rods. A dense bacterial aggregate composed mainly of rods was observed within the root canal and surrounding the apical foramen of one specimen. Beyond the apical foramen, other bacterial morphological types were recognized, including coaggregations of cocci and filaments, characterizing a fully developed 'corn cob'. CONCLUSIONS: Extraradicular bacteria were observed in one tooth out of 27 (4% of the cases).