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Background This study was conducted to compare the microbiomes, the levels of lipopolysaccharides (LPS), lipoteichoic acid (LTA), and cytokines (interleukin [IL]‐1β and tumor necrosis factor‐alpha [TNF‐α]), before and after chemomechanical preparation (CMP) of the root canals (RC) and their associated periodontal pockets (PP) in teeth with combined EPL. Materials Samples were taken from 10 RC and PP, before and after CMP. The microbiomes (next‐generation sequencing, V3‐V4 hypervariable region of the 16S rRNA gene), microbiome diversity (bioinformatics analyses), LPS (limulus amebocyte lysate), LTA, IL‐1β, and TNF‐α (ELISA) were evaluated. A statistical analysis was performed with significance level set at 5%. Results The most abundant phyla in both sites were Firmicutes and Proteobacteria. Comparative studies of bacterial genera species revealed that some increased and others decreased after CMP at both sites. A 3% reduction in Gram‐negative bacteria (RC) and a 4% increase in Gram‐positive bacteria (PP) were detected. LPS levels were 4.4 times higher in PP than in the RC. LTA was detected in all samples investigated. Higher levels of IL‐1β and TNF‐α were detected in both sites at baseline. After CMP, LPS, LTA, IL‐1β and TNF‐α were reduced in both sites. Conclusion The microbial community in the RC and PP in teeth with combined EPL indicated a similarity between both sites. CMP effectively reduced the microbial load and the LPS levels from teeth with EPL, and consequently diminished the cytokine levels. The reduction in LTA levels in the RC and PP proved challenging.

Periodontal and Endodontic diseases are biofilm-related diseases. The presence of microorganisms in root canals (RCs) and the complex microbiota of periodontal pockets (PPs) contribute to the development of endodontic-periodontal diseases. This study performed a systemic analysis using state-of-the-art sequence data to assess the microbial composition of infected RCs and PPs to further assess the microbiota and verify the possibility of cross-infection between these sites. The microbiomes of these combined diseases were examined with a focus on the V3-V4 hypervariable region of the 16S rRNA gene. The number of species in PP was higher than in RC, and there was a predominance of obligate anaerobes and gram-negative bacteria. In the RCs, the genera Enterococcus, Parvimonas, Stomatobaculum predominated, in contrast, the PPs revealed a predominance of Enterococcus, Parvimonas, Stomatobaculum, Peptostreptococcus and Mogibacterium. The RC and PP microbiome was not similar with regards to the sharing of OTUs for phyla and genera (8 and 67, respectively). The evaluation of molecular markers revealed a large number of markers for resistance to antibiotics of the carbapenem and beta-lactam type (broad spectrum). Another relevant finding of this study was the markers related to systemic diseases related to cardiac muscle and rheumatology, among others. In conclusion, the RC microbiota was less complex and diverse than PP. Interactions between microbial communities were present. The shared genus can signal communication between the endodontic and periodontal microbiomes.

Título da Aperfeiçoamento de uma técnica para extrair DNA de água do mar e comparação de métodos de extração de DNA na caracterização de uma comunidade bacteriana marinha. À minha orientadora Irma Nelly Gutierrez Rivera (in memorian), pelos ensinamentos e pelos bons momentos que sempre levarei comigo. Dedico AGRADECIMENTOS À profª Drª Irma Nelly Gutierrez Rivera (in memorian), amiga e orientadora que esteve comigo compartilhando experiências, transmitindo conhecimentos, conselhos e muita força positiva do início até o fim deste trabalho. Ao Prof. Dr. Gabriel Padilla Maldonado pelo aceite em me orientar na fase final deste estudo e por toda ajuda e apoio concedido. Ao Prof. Dr. Rubens Tadeu Delgado Duarte, pelas dicas e sugestões fornecidas, principalmente na reta final deste trabalho. À Drª Claudiana Paula de Souza Sales pela amizade, pelos ensinamentos em microbiologia e biologia molecular e por toda ajuda concedida no desenvolvimento deste estudo. Aos professores da minha banca de qualificação, Dr. Rubens Tadeu Delgado Duarte, Drª. Elisabete José Vicente e Dr. Ricardo Harakava pelas suas valiosas considerações. Ao Prof. Fernando Dini Andreote e ao seu orientado Thiago Gumiere pela orientação na realização e análise dos dados da técnica do DGGE. À minha mãe Rosa Passini e irmã Kátia Passini, pelo amor e incentivo que sempre recebo. Aos meus avós e familiares, por todo carinho e apoio. Especialmente à minha tia Irene (in memorian) e sua filha Kêkê pela ajuda nos primeiros passos dessa caminhada. À minha namorada e aos seus pais, Flávio e Eliane, pelos finais de semana divertidos e relaxantes. Agradeço especialmente à minha namorada Larissa Ortolan Levy, pelo companheirismo, carinho e amor. Você deixou todo esse trabalho mais fácil. Aos bons momentos com meus amigos do laboratório de Ecologia Microbiana Molecular, Claudiana, Bianca, Flávio, Lígia, Nadia, Thiago, Claudia, Gabriel, Caio, e é claro à amiga Vanessa. Ao Seu Lu e à Zita, pelas inúmeras ajudas no laboratório e pelos momentos de descontração.

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