Microbiote detection of root canals by microbiologic culture and molecular biology-Checkerboard DNA-DNA hybridization: histomicrobiologic, histopatologic and radiogrhafic evaluation of periapical reaction development in dogs teeth

• Grant number: 05/04599-8
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2006
• End date: August 31, 2008
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Izabel Yoko Ito
• Grantee: Izabel Yoko Ito
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The endodontic treatment of teeth with periapical periodontitis shows the minor success rate because of several microbiological and pathological interferences. The infectious status of root canals is resultant from successive changes of the pulp cavity environment in relation with oxygen tension, disposal of nutrients and metabolic changes. The periapical periodontitis development process promotes the microorganism propagation, microbiological changes, periapical inflammatory and radiographic changes. So, knowledge of periapical periodontitis development and its correlation with microbiologic, histopathologic and radiographic changes are important to the philosophy treatment elaboration. In this study it will be done the microbiologic evaluation using the culture and biologic molecular techniques. The results will be correlated with the histopathologic, histomicrobiologic and radiographic evaluation of the chronic induced periapical reaction development in dog´s teeth. It will be used 4 dogs. The root canals will be exposed to the bucal environment for 7 days and then coronal sealed during 7-60 days, according to the following experimental groups: GI- 7 days, GII- 15 days, GIII- 30 days and GIV- 60 days. At the initial period and at the experimental periods will be done standard radiographs to radiographic evaluation and material from root canals will be collected for endodontic microbiologic evaluation. The microbiologic evaluation will be done using the culture method and biologic molecular technique - Checkerboard DNA-DNA hybridization. From the analysis of microbiologic results, it will be possible to evaluate the cinetic of the endodontic microbiological changes comparing the two used methods and its correlation with the histopathologic and radiographic changes. All the experimental groups will be done in the same animals. After the experimental period and dead of the animals, it will be done the analysis of the radiographic, histopathologic and histomicrobiologic changes in the apical and periapical tissues during the development of the induced chronic periapical periodontitis at the different studied time periods. The radiographic evaluation will be done by the digitalization of the images. The periapical periodontitis radiolucencies will be measured and compared among the periods. The obtained histological sections after the demineralization process will be stained by Hematoxylin and Eosin for the histopathologic evaluation and Brown and Breen method for the histomicrobiologic evaluation. The histopathologic analysis will be done based on the inflammatory changes and apical and periapical tissue resorption. The histomicrobiologic evaluation aims to identify the extention of the microorganisms propagation to the root canal system. The obtained data will be submitted to the statistical analysis to comparison among the experimental groups and the correlation among the different evaluation methods. (AU)