For the patient in the dentist’s chair, saliva is little more than a nuisance—a potential cause of drowning or embarrassment from drooling. But this humble bodily fluid is essential for oral health and for systemic health as well.
Saliva is 98 percent water. The remaining 2 percent is made of proteins, electrolytes, enzymes, hormones, and other compounds, including antioxidants. Saliva helps soften food and begin the breakdown process of digestion. It also lubricates the teeth and tongue, and helps wash away particles of food. Saliva also contains natural antibiotics, a first line of defense against bacteria and infection.
A major component of saliva’s defense system is a rich array of antioxidants, including uric acid, albumin, ascorbic acid, glutathione and antioxidant enzymes. These antioxidants neutralize free radicals that contribute to inflammation.
Free Radical Attack
Free radicals are unstable molecules with an unpaired electron. When the unstable free radical finds another molecule, it may steal an electron to complete its pair. This leaves the second molecule with an unpaired electron, that is, as a new free radical. This stealing process or electron theft—what is known as oxidation—can become a chain reaction.
Some free radical molecules occur naturally as metabolism converts food to energy in a gradual form of oxidation. Free radicals can also be generated by other substances or activities within the body. In the oral cavity, nicotine, alcohol, or dental materials and procedures can increase the concentration of free radicals.
Free radicals that accumulate during the oxidation process cause “oxidative stress.” Unchecked, oxidative stress and free radicals can cause tissue damage, and provoke inflammation. Inflammation has been identified as a common ‘bad actor’ in both oral disease and systemic disease.
Also, recent research has shown a correlation between low levels of antioxidants in saliva and a higher incidence of oral cancer in elderly people.
Antioxidants: Defense Against Free Radicals
Fortunately, antioxidant molecules safely interact with free radicals and terminate the chain reaction before vital cell molecules are damaged. Antioxidants are large, complex molecules that bind with the unpaired electrons of free radicals, effectively neutralizing them. Different antioxidants work in different ways to either stop or retard the chain-reaction process of oxidation.
The antioxidants in saliva are critical for fighting free radicals and oxidative stress. However, the natural levels of saliva may be insufficient to combat high levels of free radicals caused by oral infection, systemic inflammation, or toxic substances. Increasingly, dental professionals are looking for ways to fight inflammation by increasing the level of antioxidants in the oral cavity. Topical antioxidants that are applied directly to the oral tissues are an emerging technology with great potential.
Fighting infection, reducing inflammation, fending off cancer. Simple saliva is a mighty force in the oral cavity’s natural defense system.