published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

Recent studies regarding research on oral microorganisms and the oral diseases are presented. The normal flora of the mouth and the oral environment are first described. Dental plaque and dental caries are primary causes of oral disease. Streptococcus mutans is the major contributor in the initiation and progression of dental caries. Lactobacillus, Actinomyces, and Veillonella are other genera of bacteria linked to dental caries. Periodontitis and gingivitis are periodontal diseases that are caused by oral microorganisms. New research has indicated that various antimicrobial agents and techniques to eliminate or lessen the severity of periodontal diseases. Premature delivery of low birth weight babies in pregnant women has been strongly linked to periodontal disease. Present and future microbiological tests are available to easily determine the causative organisms for most oral diseases that help in diagnosis and treatment of a particular disease.

published_or_final_version / Dentistry / Master / Master of Dental Surgery

Increasing evidence suggests that the oral microbiome is highly relevant to cardiometabolic outcomes. Associations between the oral microbiome and extra-oral outcomes are most commonly hypothesized to result from a chronic inflammatory response to a dysbiotic oral microbiome. However, an alternative mechanism hypothesized to link the oral microbiome to cardiometabolic risk is via the production of nitric oxide, a physiologically important gaseous transmitter. The enterosalivary nitrate-nitrite-nitric oxide pathway of nitric oxide generation is dependent on the presence of nitrate-reducing oral bacteria in the mouth to reduce salivary nitrates to nitrite, which are then swallowed and made systemically bioavailable for further reduction into nitric oxide in the blood vessels and tissues. Thus, this pathway presents a mechanism for oral bacteria to exert a beneficial influence on cardiometabolic health. The overall objective of this dissertation is to advance the understanding of the role of nitrate-reducing oral bacteria in cardiometabolic outcomes in a population setting. This objective was met using three aims. First, a systematic literature review was conducted to identify and assess the associations between nitrate-reducing oral bacteria and insulin resistance, plasma glucose, diabetes, blood pressure and hypertension found in the existing literature. The literature review found no study that explicitly tested the hypothesis of an association between nitrate-reducing oral bacteria and the cardiometabolic outcomes of interest. In addition, there were very few observed associations between nitrate-reducing oral bacteria and these cardiometabolic outcomes, and the findings were inconsistent across studies. Secondly, the associations between nitrate-reducing oral bacteria and insulin resistance, plasma glucose, blood pressure, prediabetes and hypertension were assessed using baseline data from a cohort of diabetes-free participants. Increased levels of oral nitrate-reducing bacteria were associated with lower insulin resistance, plasma glucose and mean systolic blood pressure cross-sectionally, but no associations were found with prediabetes and hypertension. Finally, as dietary nitrate intake influences the level of salivary nitrate in the mouth for the nitrate-reducing oral bacteria to act on, the associations between dietary nitrate and insulin resistance, plasma glucose, blood pressure, prediabetes and hypertension were assessed. No clear associations between higher dietary nitrate intake and the cardiometabolic outcomes were found. However, there was some indication that higher dietary nitrate intake was associated with lower systolic blood pressure. The interaction of dietary nitrate intake with nitrate-reducing oral bacteria was then considered, but no evidence of such interaction was found. Overall, the results of this dissertation suggest that higher levels of nitrate-reducing oral bacteria may confer health benefits across the range of bacterial levels likely observed in human populations. These findings help inform future public health research aimed at utilizing the enterosalivary pathway of nitric oxide generation to improve cardiometabolic health.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Dentistry / Master / Master of Philosophy

This study evaluated the stability of oral bacteria in healthy subjects and documented community shifts in smokers and oral/periodontal disease by employing PCR-RFLP, DGGE and sequence analysis of the 16S rDNA gene from metagenomes and plate-wash (cultured) bacteria of oral wash from 15 participants,. A stable core of bacterial DNA fingerprint was detected within and between subjects and did not change over time when analyzed in smokers and healthy non-smokers. Signature bands in smokers, non-smokers and periodontal disease subjects were evident suggesting the presence of potential indicators of health and poor oral health. Taxon diversity was higher in smokers including members of the genera Rothia, Synechococcus, Neisseria, Thiomargarita and Pyrobaculum but highest in periodontal disease. The two techniques successfully aligned the subjects within appropriate categories (based on their oral microbial genetic patterns)confirming their diagnostic suitability. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Made available in DSpace on 2014-06-11T19:27:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-20Bitstream added on 2014-06-13T19:35:56Z : No. of bitstreams: 1 pereira_ts_me_araca.pdf: 812104 bytes, checksum: 1bc4169e4989448b7fbb588f374a8363 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A assistência integral ao paciente autista visa proporcionar melhor qualidade de vida, dela fazendo parte o acompanhamento e tratamento odontológico. Assim, diante da escassez de informações sobre o perfil de saúde bucal destes pacientes e da dificuldade em atendê-los, o presente estudo avaliou as condições de saúde bucal de pacientes autistas bem como as características da microbiota, fatores sócio-econômicos, culturais e comportamentais. As características sócio-econômicas, culturais e comportamentais foram avaliadas através de um questionário especialmente preparado para este fim. A seguir, realizou-se a coleta dos espécimes clínicos do biofilme bucal para a caracterização da microbiota presente através de cultura e amplificação do DNA microbiano por PCR. As condições de saúde bucal foram analisadas através de exame clínico bucal, por meio da avaliação clínica da saúde gengival e dentária. Com relação à microbiota bucal, foi possível detectar, por meio de cultura, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermédia, Pseudomonas e Fusobacterium nucleatum. Já para a Reação em Cadeia da Polimerase (PCR), houve a detecção de Campylobacter rectus, Actinobacillus actinomycetemcomitans, Eikenella corrodens, Porphyromonas gingivalis, Prevotella intermédia, Enterobacter, Treponema dentícola e Fusobacterium nucleatum, porém estes microorganismos não foram capazes de promover doenças periodontais pois os resultados obtidos evidenciaram que a maioria dos pacientes apresentava boa saúde bucal e possuía o hábito de realizar higiene bucal (Índice de Higiene Oral Simplificado ótimo), apesar de serem dependentes e oferecerem resistência para esta atividade. Podemos concluir que o autismo ocorre em maior número no gênero masculino; são dependentes e resistentes às atividades de higienização dental, mas no geral... / The full assistance to the autistic patient aims to provide better life quality and, consequently, to afford follow-up and dental treatment. Thus, due to the lack of information on the oral health profile of these patients and due to the difficulty to assist them, this study evaluated the oral health conditions of autistic patients as well as the characteristics of their oral microbiology and socio-economic, cultural and behavioral factors. The socio-economic, cultural and behavior factors were assessed through a questionnaire specially prepared for this purpose. Then, clinical specimens of oral biofilm were collected in order to accomplish the microflora characterization, through culture and microbial DNA amplification by Polymerase Chain Reaction (PCR) test. Oral health conditions were evaluated through clinical oral examination, by means of dental and gingival health clinical evaluations. Regarding the oral microbiology, it was possible to detect, by culture test: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Pseudomonas. Now concerning the PCR test, the following bacteria were detected: Campylobacter rectus, Actinobacillus actinomycetemcomitans, Eikenella corrodens, Porphyromonas gingivalis, Prevotella intermedia, Enterobacter, Fusobacterium nucleatum and Treponema denticola, but these microorganisms were not able to promote periodontal diseases in autistic patients, because the results showed that most of them had good oral health and oral hygiene practices (great IHOS), although they are dependent and offer resistance to this activity. We concluded that autism occurs in greater numbers in males; they are dependent and resistant to dental hygiene activities, but, in general, they have good oral health, although they presented oral microorganisms associated to periodontal diseases.