Dental caries, more commonly referred to as cavities or tooth decay, is a widespread disease in humans estimated to directly affect around 3.5 billion people worldwide. Following recent advances in molecular and genetic technologies over the last several decades, it is commonly understood that the human body is inhabited by a diverse and vast quantity of microorganisms, collectively referred to as the microbiome. The microbiome has been increasingly tied to fluctuations in both human health and disease. Current understandings of these interactions have shifted the model for many diseases, especially dental caries, to be the result of complex interplays between the human host and the microscopic organisms living around and within it. The molecular activities of several oral cavity bacteria are specifically significant in the initiation and progression of the caries process. These molecular activities are closely tied to regular fluctuations in the environment of the oral cavity, particularly acidification and dietary intake of carbohydrates, that select for the proliferation of cariogenic species of bacteria. Of particular interest in this thesis are species of the Actinomyces genus and how various environmental fluctuations influence the genetic expression of these bacteria and consequentially lead to the development of plaque on the enamel surface of human teeth. The caries process will be investigated through the lens of the most modern theory of caries progression, the Ecological Plaque Hypothesis, and the role of Actinomyces in this process will be considered. In this thesis, it is hypothesized that the extracellular expression of the common heat-shock protein (Hsp) known as GroEL is upregulated due to an increase in concentration of acidic byproducts produced by neighboring bacteria species as well as other environmental perturbations. The role of extracellular GroEL in attachment to the enamel surface by Actinomyces species was suggested to play an essential role in development of a cariogenic bacterial profile within enamel-associated plaque. This initial Actinomyces attachment and subsequent plaque proliferation is essential for the initiation of the caries process. Environmental and molecular factors such as short-chain fatty acids and variable pH will be considered as they are related to the development of carious lesions on the tooth surface. The impact of diet on this process will also be considered and this will be related to dietary discrepancies across various human populations in America. These factors will be tied together by looking at the oral health interventions being done by Boston University in the surrounding community, and conclusions regarding potential therapeutic practices will close out the discussion.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/45526 |
| Date | 27 January 2023 |
| Creators | Allen, Mitchell |
| Contributors | Samuelson, John C., Moussavi, Mina |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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