Saliva is a key component to the
oral environment since it plays a large part of
anti-microbial actions and also acts as a way to provide for
bacterial buildup on the teeth especially since it contains
lysozyme, an anti-microbial enzyme that helps protect
surfaces.
The
pH of saliva is strictly controlled by a
bicarbonate buffering system and is usually between 5.7 and 7.0, creating a relatively stable
environment. The higher the pH of the
oral cavity, the better the buffering capacity of the saliva. A low pH indicates susceptibility to the effects of
acid production. The pH of the saliva also affects the types of bacteria that inhabit the oral cavity since most bacteria have a small pH range that they are tolerant to.
However, saliva contains many
nutrients that promote
bacterial growth and even with the antimicrobial substances, the presence of these and food from the host’s diet creates a
favorable environment for
bacteria.
Info from:
Tortora, G.J., B.R.Funke, and C.L. Case, 2001. Microbiology: An Introduction, 7th edition. New York, New York.
Madigan, M.T., J.M. Martinko, and J. Parker, 2000. Biology of Microorganisms, 9th edition. Upper Saddle River, New Jersey.