Mouth
Introduction
The dark, wet, and warm environment of the mouth, with the occasional meal running through it, makes it an excellent niche for microbes to live. Over the past 40 years, scientists have been arduously working to discover the over 500 different species of bacteria in and around the mouth known today. The mouth is comprised of an oral cavity, which includes the teeth and gums, surrounded by the lips, cheeks, tongue, palate, and throat (Figure 1). Each of these habitats offers differing environmental conditions (Figure 2), and as such, is colonized by a different microbial flora. The oral environment is constantly in flux. From birth to around age 12, when the permanent dentition is complete, the local oral conditions are continuously changing as teeth are shed and new ones erupt (The Normal Microbial Flora of Man). In addition, environmental factors such as, nutrition, diet, hygiene, smoking, dehydration, and even stress, alter the ecological conditions of mouth. Saliva covers all surfaces and serves various important functions, mechanical and nutritional, (digestive, swallowing, cleansing, lubricative, bactericidal, and excretory) in the oral cavity. It is comprised of various proteins and glycoprotein, of which the main constituents include salivary mucins (approximately 25% of saliva), amylase, IgA, and lysozyme. The typical resting pH (6.5-6.9) is slightly more acidic than stimulating pH (7.0-7.5), but often varies depending on the secretion rate. (Indigenous Microbiota of the oral cavity). While salivary flora does not necessarily represent the microbial composition of the different components of the mouth, it does impact which microbes can live within the oral cavity, and has recently been the target of research in early disease detection (link to current research).
Teeth
Physical Conditions?
What are the conditions in your niche? Temperature, pressure, pH, moisture, etc.
Influence by Adjacent Communities (if any)
Is your niche close to another niche or influenced by another community of organisms?
Conditions under which the environment changes
Do any of the physical conditions change? Are there chemicals, other organisms, nutrients, etc. that might change the community of your niche.
Who lives there?
Which microbes are present?
You may refer to organisms by genus or by genus and species, depending upon how detailed the your information might be. If there is already a microbewiki page describing that organism, make a link to it.
Are there any other non-microbes present?
Plants? Animals? Fungi? etc.
Do the microbes that are present interact with each other?
Describe any negative (competition) or positive (symbiosis) behavior
Do the microbes change their environment?
Do they alter pH, attach to surfaces, secrete anything, etc. etc.
Do the microbes carry out any metabolism that affects their environment?
Do they ferment sugars to produce acid, break down large molecules, fix nitrogen, etc. etc.
Gingiva
Where located?
Physical Conditions?
What are the conditions in your niche? Temperature, pressure, pH, moisture, etc.
Influence by Adjacent Communities (if any)
Is your niche close to another niche or influenced by another community of organisms?
Conditions under which the environment changes
Do any of the physical conditions change? Are there chemicals, other organisms, nutrients, etc. that might change the community of your niche.
Who lives there?
Which microbes are present?
You may refer to organisms by genus or by genus and species, depending upon how detailed the your information might be. If there is already a microbewiki page describing that organism, make a link to it.
Are there any other non-microbes present?
Plants? Animals? Fungi? etc.
Do the microbes that are present interact with each other?
Describe any negative (competition) or positive (symbiosis) behavior
Do the microbes change their environment?
Do they alter pH, attach to surfaces, secrete anything, etc. etc.
Do the microbes carry out any metabolism that affects their environment?
Do they ferment sugars to produce acid, break down large molecules, fix nitrogen, etc. etc.
Tongue
Where located?
Physical Conditions?
What are the conditions in your niche? Temperature, pressure, pH, moisture, etc.
Influence by Adjacent Communities (if any)
Is your niche close to another niche or influenced by another community of organisms?
Conditions under which the environment changes
Do any of the physical conditions change? Are there chemicals, other organisms, nutrients, etc. that might change the community of your niche.
Who lives there?
Which microbes are present?
You may refer to organisms by genus or by genus and species, depending upon how detailed the your information might be. If there is already a microbewiki page describing that organism, make a link to it.
Are there any other non-microbes present?
Plants? Animals? Fungi? etc.
Do the microbes that are present interact with each other?
Describe any negative (competition) or positive (symbiosis) behavior
Do the microbes change their environment?
Do they alter pH, attach to surfaces, secrete anything, etc. etc.
Do the microbes carry out any metabolism that affects their environment?
Do they ferment sugars to produce acid, break down large molecules, fix nitrogen, etc. etc.
Throat
Where located?
Physical Conditions?
What are the conditions in your niche? Temperature, pressure, pH, moisture, etc.
Influence by Adjacent Communities (if any)
Is your niche close to another niche or influenced by another community of organisms?
Conditions under which the environment changes
Do any of the physical conditions change? Are there chemicals, other organisms, nutrients, etc. that might change the community of your niche.
Who lives there?
Which microbes are present?
You may refer to organisms by genus or by genus and species, depending upon how detailed the your information might be. If there is already a microbewiki page describing that organism, make a link to it.
Are there any other non-microbes present?
Plants? Animals? Fungi? etc.
Do the microbes that are present interact with each other?
Describe any negative (competition) or positive (symbiosis) behavior
Do the microbes change their environment?
Do they alter pH, attach to surfaces, secrete anything, etc. etc.
Do the microbes carry out any metabolism that affects their environment?
Do they ferment sugars to produce acid, break down large molecules, fix nitrogen, etc. etc.
Current Research
1. Correlation between periodontitis and coronary heart disease
Several theories exist to explain the relationship between coronary heart disease and periodontitis. One such theory includes the role of fibrinogen in linking the two. Fibrinogen is a plasma glycoprotein synthesized in the liver. After coagulation, it is converted in Fibrin, the protein involved in blood clots. The study took 95 subjects and separated them into a healthy control group, moderately and severely chronic periodontitis group, coronary heart disease group, and moderately and severely chronic periodontitis coexisting with coronary heart disease group. After measuring routinely diagnosis procedure for both periodontitis and cardiovascular heart disease along with levels of fibrinogen, results showed fibrinogen levels in subjects with MSP and MSP+CHD to be much higher than those of the healthy controlled group. It was concluded that people with periodontitis may be more at risk for developing cardiac heart disease when taking into consideration fibrinogen as the biological basis.
2. Bacterial markers of periodontal diseases
Among the various bacteria present in the subgingival deposit, three have been the center of study due to their prevalence in periodontal disease. First, the Tannerella forsythensis, an anaerobic Gram-negative known to possess pathogenic potential. Second, the Actinobacillus actinomycetemcomitans with the ability to attach itself to the enamel surface after the consumption of sugar to produce an acid resulting in the erosion of the enamel surface. And the third, the Porphyronmonas gingivalis, a gram negative bacteria with a virulence factor allowing it to invade the gum tissue. They measure the bacteria on 495 subjects aged 6-82 with the use of the 16S ribosomal RNA based polymerase chain reaction (PCR). Their studies showed an increase in the amount of T. forsythensis and P. gingivalis on older subjects when compared to the adolescents. Furthermore, an increase in T. forsythensis was also seen within the tobacco smokers or the subjects. It was finally concluded that the T. forsythensia had a correlation between periodontal disease in tobacco smoking and elder individuals.
3. Saliva used as Biomarkers for early disease detection
Current research is being done in the mouth to help detect diseases throughout the entire body. As of now, some hard hitting diseases: cancer, cardiovascular diseases, metabolic and neurological deficits are tough to diagnose especially early on. The research is aimed at providing scientists and doctors a simple, inexpensive way to diagnose these diseases through finding disease-associated proteins and genetic markers in saliva. Saliva dectection is already being used to detect HIV, hepatitis A, B, C, and is used to monitor some drugs like marijuana. The NIDCR is currently working on finding the body’s disease-associated salivary biomarkers for those hard to diagnose diseases than developing an accurate, easy to use diagnostic method (Wong).
4. Fluorinated food
For a while now some researchers have been looking into fluorinating food sources. This is done with the thought that because fluoride is the best way of preventing big plaque build up on the tooth, since plaque is linked with gingivitis, periodontal disease, and other oral disease. This current research finds that fluorinating food in populations where fluoride toothpaste and daily brushing has almost no additional beneficial effects. The big reason in wanting to fluorinate food is too possibly fight oral diseases in other countries in which brushing is not practiced regularly. This experiment shows that without the brushing, fluorinated foods have a small but significant effect on controlling plaque it also shows that fluorinated foods should not be substituted for brushing with fluorinated toothpaste (Meyer-Luekel).
References
Chukhlovin AB, Solovyova AM, Matelo SK, Kobiyasova IV, Morosova EB, Hokhlacheva AV, Teplyakov BG, Syssoev KA, Konstantinova VE, Matelo LN, Totolian AA. “Bacterial markers of periodontal diseases and their practical significance in dentistry.” Bull Exp Biol Med. 2007 Oct;144(4):546-50. PMID: 18642710 http://www.ncbi.nlm.nih.gov/pubmed/18642710?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
Ge S, Wu YF, Liu TJ, Meng S, Zhao L. “Study of the correlation between moderately and severely chronic periodontitis and coronary heart disease”, Hua Xi Kou Qiang Yi Xue Za Zhi. 2008 Jun;26(3):262-6. PMID: 18705507 http://www.ncbi.nlm.nih.gov/pubmed/18705507?ordinalpos=18&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pub
Mydel P, Takahashi Y, Yumoto H, Sztukowska M, Kubica M, Gibson FC 3rd, Kurtz DM Jr, Travis J, Collins LV, Nguyen KA, Genco CA, Potempa J. “Roles of the host oxidative immune response and bacterial antioxidant rubrerythrin during Porphyromonas gingivalis infection.” PLoS Pathog. 2006 Jul;2(7):e76. PMID: 16895445 http://www.ncbi.nlm.nih.gov/pubmed/16895445?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
Rautemaa R, Järvensivu A, Kari K, Wahlgren J, DeCarlo A, Richardson M, Sorsa T. Oral Dis. 2004 Sep;10(5):298-305. “Intracellular localization of Porphyromonas gingivalis thiol proteinase in periodontal tissues of chronic periodontitis patients.” PMID: 15315648 http://www.ncbi.nlm.nih.gov/pubmed/15315648?ordinalpos=8&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
Yang R, Zou J, Li JY. “Study of the relationship between oral Actinomyces and childhood caries.” Hua Xi Kou Qiang Yi Xue Za Zhi. 2007 Dec;25(6):568-70. PMID: 18306628 http://www.ncbi.nlm.nih.gov/pubmed/18306628?ordinalpos=13&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
Frederick JF, Rogers EA, Marconi RT. Analysis of a growth phase regulated-two component regulatory system in the periodontal pathogen, Treponema denticola. J Bacteriol. 2008 Jul 11. PMID: 18621891 http://www.ncbi.nlm.nih.gov/pubmed/18621891?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
A S McDermid, A S McKee, and P D Marsh. “Effect of environmental pH on enzyme activity and growth of Bacteroides gingivalis W50.” Infect Immun. 1988 May; 56(5): 1096–1100. PMCID: PMC259768 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=259768
Edited by Mason Chen, Diana Kirchmann, Alvin Kwong, Lydi Martinez, Mei Ng, Gabriel Tran, Kristen Watanabe, Kathryn Yee students of Rachel Larsen
