24.2 Microbial diseases of the mouth and oral cavity  (Page 2/8)

To prevent tooth decay, prophylactic treatment and good hygiene are important. Regular tooth brushing and flossing physically removes microbes and combats microbial growth and biofilm formation. Toothpaste contains fluoride , which becomes incorporated into the hydroxyapatite of tooth enamel , protecting it against acidity caused by fermentation of mouth microbiota. Fluoride is also bacteriostatic, thus slowing enamel degradation. Antiseptic mouthwashes commonly contain plant-derived phenolics like thymol and eucalyptol and/or heavy metals like zinc chloride (see Using Chemicals to Control Microorganisms ). Phenolics tend to be stable and persistent on surfaces, and they act through denaturing proteins and disrupting membranes.

Regular dental cleanings allow for the detection of decay at early stages and the removal of tartar . They may also help to draw attention to other concerns, such as damage to the enamel from acidic drinks. Reducing sugar consumption may help prevent damage that results from the microbial fermentation of sugars. Additionally, sugarless candies or gum with sugar alcohols (such as xylitol ) can reduce the production of acids because these are fermented to nonacidic compounds (although excess consumption may lead to gastrointestinal distress). Fluoride treatment or ingesting fluoridated water strengthens the minerals in teeth and reduces the incidence of dental caries .

If caries develop, prompt treatment prevents worsening. Smaller areas of decay can be drilled to remove affected tissue and then filled. If the pulp is affected, then a root canal may be needed to completely remove the infected tissues to avoid continued spread of the infection, which could lead to painful abscesses .

Periodontal disease

In addition to damage to the teeth themselves, the surrounding structures can be affected by microbes. Periodontal disease is the result of infections that lead to inflammation and tissue damage in the structures surrounding the teeth. The progression from mild to severe periodontal disease is generally reversible and preventable with good oral hygiene.

Inflammation of the gums that can lead to irritation and bleeding is called gingivitis . When plaque accumulates on the teeth, bacteria colonize the gingival space . As this space becomes increasingly blocked, the environment becomes anaerobic. This allows a wide variety of microbes to colonize, including Porphyromonas , Streptococcus , and Actinomyces . The bacterial products, which include lipopolysaccharide (LPS), proteases , lipoteichoic acids , and others, cause inflammation and gum damage ( [link] ). It is possible that methanogenic archaeans (including Methanobrevibacter oralis and other Methanobrevibacter species) also contribute to disease progression as some species have been identified in patients with periodontal disease , but this has proven difficult to study. Hans-Peter Horz and Georg Conrads. “Methanogenic Archaea and Oral Infections—Ways to Unravel the Black Box.” Journal of Oral Microbiology 3(2011). doi: 10.3402/jom.v3i0.5940. Hiroshi Maeda, Kimito Hirai, Junji Mineshiba, Tadashi Yamamoto, Susumu Kokeguchi, and Shogo Takashiba. “Medical Microbiological Approach to Archaea in Oral Infectious Diseases.” Japanese Dental Science Review 49: 2, p. 72–78. Paul W. Lepp, Mary M. Brinig, Cleber C. Ouverney, Katherine Palm, Gary C. Armitage, and David A. Relman. “Methanogenic Archaea and Human Periodontal Disease.” Proceedings of the National Academy of Sciences of the United States of America 101 (2003): 16, pp. 6176–6181. doi: 10.1073/pnas.0308766101. Gingivitis is diagnosed by visual inspection, including measuring pockets in the gums, and X-rays, and is usually treated using good dental hygiene and professional dental cleaning, with antibiotics reserved for severe cases.