It has been known for a while that saliva naturally protects our teeth and gums from the effects of tooth decay caused by the bacteria in plaque. A recent study indicates that the mucus portion of the saliva is particularly beneficial when it comes to fighting this strain of bacteria.
Saliva is comprised of 99.5% water, with mucus making up the remaining portion of it. Salivary mucins are compounds found in that mucus, and they are the element that protects teeth from the cavity-causing bacteria known as Streptococcus mutans. It turns out that salivary mucins do not exactly kill the bacteria, as much as keep it suspended in a liquid medium. This is significant because this prevents the bacteria from being able to form biofilms on the teeth. Bacteria from plaque are only able to cause damage to our teeth when they are attached to our teeth in a biofilm. The lack of attachment encourages an easier removal through normal brushing and flossing techniques, thus lowering our risk of cavities.
One of the takeaways from the study was that bolstering the natural defenses that our body already has may be a better way to prevent tooth decay than using external methods such as sealants to protect against decay. It is important to prevent tooth decay, because if it is allowed to move past the enamel layer and then the dentin layer of our tooth, it will reach the pulp and effectively kill the nerve of the tooth. The only way to save it at this point is through a root canal procedure, which is a great treatment to have at our disposal, but it would be much better to prevent decay from ever reaching the pulp of our tooth in the first place.