University of Iowa Health Science Relations
First Published: June 2003
Peer Review Status: Internally Peer Reviewed

It's something you probably consider gross or disgusting, not beneficial. You probably don't even think about it much at all. But if it disappears, you'll wish you had your saliva back.

Saliva does more than just help us chew food--it protects teeth by preventing decay, regulating your mouth's acidity level and keeping bacteria in your mouth from running rampant.

But when saliva's lacking, plaque builds, enamel erodes, cavities quickly form and fungal growth runs rampant.

"I don't think that people realize the importance of saliva until the well runs dry," said Ana Diaz-Arnold, DDS, University of Iowa professor of family dentistry. "Saliva is critical for your dental health."

The milliliter of saliva normally in our mouth acts as a buffer, adjusting the pH level of the mouth as we consume acidic foods and drinks. It also prevents plaque from easily attaching to teeth.

"Saliva is kind of like a car wash--a constant cleaning mechanism," Diaz-Arnold said.

But the average liter of saliva that we produce in a day can diminish or disappear for a variety of reasons, resulting in xerostomia, or dry mouth. Radiation to the head and neck to treat cancer can destroy the salivary glands. Sjogren's syndrome, an autoimmune disease, causes dry eyes and dry mouth. However, the most common cause of chronic dry mouth is about 400 different prescription medications, affecting people of every age group.

Dry mouth is a side effect of many heart medications, antihistamines (used for asthma and allergies), antidepressants and mood-altering drugs like Ritalin. Being on more than one of these medications makes the dry mouth even worse, Diaz-Arnold said.

Most patients don't realize that dry mouth is a serious problem until it's too late, when cavities abound, teeth begin to rot or yeast infections form inside the mouth. Patients should contact their dentist right away when they begin a medication that lists dry mouth as a side effect.

Even before decay starts, people with chronic dry mouth will find the condition affecting their everyday lives.

"People with dry mouth often wake up in the middle of the night because their mouth is uncomfortably dry," said Cindy Marek-Thompson, PharMD, UI associate professor (clinical) of dentistry and pharmacy. "It also becomes difficult to swallow food because they don't have the lubricant effect of saliva."

Cutting out drinks and food high in sugar and acid levels, like pop, sports drinks and candy, are the first things a person with dry mouth should do.

To stimulate salivary flow, Diaz-Arnold recommends drinking lots of water, chewing sugarless gum and sucking on sugar-free hard candies. Avoid lemon candy or cough drops, which are highly acidic, as well as caffeine and alcohol (including in mouthwashes), which can dry out the mouth. Drinking milk with meals also can promote moisture.

Increasing the humidity in the house, usually by running a cool air humidifier at night, also helps to alleviate symptoms of dry mouth, according to Marek-Thompson. She also notes the importance of making frequent visits to a dental practitioner for cleanings and checkups. Dentists may prescribe fluoride rinses or toothpastes with higher fluoride content to help re-mineralize the teeth.

Diaz-Arnold also suggests that patients ask their physician about taking dry-mouth-causing medications during the day, as salivary flow is cyclic and decreases to almost nothing while we sleep. Taking medications that cause dry mouth at night will only make the problem worse, she said. It is also critical to brush your teeth before going to bed, in order to stimulate saliva flow.

Medications that cause dry mouth affect all age groups and can have serious consequences on the dental health of children and teenagers.

"I should not be seeing this amount of disease in 15-, 16- and 17-year-olds," Diaz-Arnold said. "The younger kids are on medications like Ritalin and Prozac and they're drinking more soda pop, resulting in dry mouth and decay."

Older patients with dentures and partials also need to take precautions against a dry mouth. Without saliva acting as a lubricant, sores can form.

"I tell patients it's like driving a car without motor oil," Diaz-Arnold said.

Until dry mouth is no longer a side effect of medications, drinking water is the best thing to treat a dry mouth. Over-the-counter saliva stimulants and substitutes do exist, but are generally expensive and short lasting.

"Unfortunately, there is no real substitute for saliva," Diaz-Arnold said.

However, research is attempting to help people suffering from xerostomia. Scientists are working on gene therapy, improved artificial saliva and artificial salivary glands.

"Quite a but of research is going into it, but that of course is never enough," Diaz-Arnold said.