What causes dry mouth —
and what treats it
The three pints of saliva that the average healthy adult produces
every day may be the most underrated body fluid. Saliva jump-starts
digestion, dissolving and adding moisture to food so it's easier to
swallow. It breaks down starch with a digestive enzyme called amylase.
Saliva contains bicarbonate, which acts as a buffering agent that offsets
the enamel-corroding acid produced by bacteria. Salivary antibodies
and protein also fend off dental bacteria as well as other infectious
agents. Saliva helps you speak clearly by keeping your mouth moist
and allowing the tongue — which is essential to forming many
sounds — to stay agile.
Compared with other medical problems, dry mouth, or xerostomia, may
be little more than an annoyance: eating is a little less pleasant and
speech a little more difficult. But for people who have little or no
saliva, persistent xerostomia is a serious and often uncomfortable condition
that can jeopardize oral health. It makes eating and swallowing difficult,
causes bad breath, and may irritate mouth tissues, leaving them more
vulnerable to infection. Dry mouth also increases the risk for tooth
decay and gum disease.
The treatment of dry mouth depends on its cause. For a long time, many
doctors thought xerostomia was a natural consequence of aging. Now most
experts agree that the vast majority of xerostomia cases are side effects
of the many medications older people take, rather than aging itself.
The culprits include blood pressure medications, antidepressants, muscle
relaxants, antihistamines, asthma drugs, and painkillers. Xerostomia
can also be caused by radiation treatment for head and neck cancer; in
killing the cancer, the radiation also knocks out the salivary glands.
Other sources of the condition are chemotherapy drugs and various chronic
diseases, including diabetes, Parkinson's disease, and an autoimmune
condition called Sjogren's syndrome.
Something as simple as frequently sipping water can alleviate dry mouth.
Sour foods stimulate the salivary glands, so lemon-flavored lozenges
can be helpful. Various types of lozenges designed to produce saliva-like
moisture are also available. Sjögren's and head and neck cancer
patients have been treated somewhat successfully with pilocarpine mouthwashes
and tablets. But pilocarpine is a strong medicine that needs to be used
carefully. It is also used to treat glaucoma, but has fallen out of favor
because it can limit night vision and cause chronic inflammation in the
Artificial salivas (including Salivart Synthetic Saliva, Saliva Substitute,
and Salix), which contain saliva-like lubricating agents, are sold in
most drugstores and can be purchased without a prescription. Some brands
come in handy little spray canisters like the mouth sprays used for bad
breath. But many people have found that artificial salivas don't last
very long and aren't that effective. If you are older, talk to your dentist
about fluoride treatments or mouthwashes as a way of combating the greater
risk of tooth decay that accompanies dry mouth. Many people learn to
live with dry mouth; they figure it's a small price to pay for the benefits
of medications and treatments. But if it gets to be serious, xerostomia
can itself be a condition that deserves your doctor's and dentist's attention.
June 2003 Update
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