Environment
The ecological factors provided by the environment of the oral cavity are directly proportional to the species richness and species biodiversity of the microorganisms that reside on the teeth. The main ecological factors are pH, saliva, temperature and redox reactions. The majority of microbial organisms prefer neutral pH levels (pH 7). Saliva acts as a buffer, maintaining the pH in the mouth between 6.75 and 7.25. In addition to acting as a buffer, saliva is also a main source of nutrients for the thousands of bacteria (note: gingival crevicular fluid is also a nutrient source but a smaller one ). A two degree (°C) change has been shown to drastically shift the dominant species in the plaque. The normal temperature of the mouth ranges between 35–36°C (Marsh). Redox reactions are carried out by aerobic bacteria. This keeps the oxygen levels in the mouth at a semi-stable homeostatic condition. This allows other bacteria to survive, which will be discussed in the next section.
Read more about this topic: Dental Plaque
Famous quotes containing the word environment:
“The poorest children in a community now find the beneficent kindergarten open to them from the age of two-and-a-half to six years. Too young heretofore to be eligible to any public school, they have acquired in their babyhood the vicious tendencies of their own depraved neighborhoods; and to their environment at that tender age had been due the loss of decency and self-respect that no after example of education has been able to restore to them.”
—Virginia Thrall Smith (1836–1903)
“We learn through experience and experiencing, and no one teaches anyone anything. This is as true for the infant moving from kicking to crawling to walking as it is for the scientist with his equations. If the environment permits it, anyone can learn whatever he chooses to learn; and if the individual permits it, the environment will teach him everything it has to teach.”
—Viola Spolin (b. 1911)
“Modern man’s capacity for destruction is quixotic evidence of humanity’s capacity for reconstruction. The powerful technological agents we have unleashed against the environment include many of the agents we require for its reconstruction.”
—George F. Will (b. 1941)