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.