How does saliva affect plaque buildup on the teeth?

Saliva plays an important role in the development and maintenance of a healthy plaque biofilm. Proteins from saliva enable the biofilm to attach to the tooth's surface. After a tooth is cleaned, its enamel surfaces quickly become coated with a salivary protein film, the pellicle. The pellicle supports the attachment of free-floating bacteria (planktonic) that are the first settlers of a new biofilm. As bacteria begin to attach to one another, they pave the way for attachment by other bacteria in a very specific order and pattern. Over the course of about three days, as plaque biofilm grows to maturity, it depends mainly on saliva for nutrition and the removal of waste. As the biofilm approaches maturity, it releases planktonic bacteria back into the saliva. Saliva then transports these free-floating bacteria to sites where a new biofilm will form.

Passive and active immune proteins within saliva regulate the growth and movement of the plaque biofilm. There is strong evidence today that the microbes and immune system have evolved together and they work as a team to prevent visiting microorganisms from residing in the mouth. The mature plaque biofilm also is dependent on salivary flow. When flow is reduced the various organisms and structures within the biofilm undergo changes that often lead to inflammatory changes in the supporting tissues.