9/1/2006 Dallas/Fort Worth staff Star-Telegram.com (www.dfw.com) Water's good. Sugar-free gum helps. But Listerine may dry out your mouth. Saliva is a health drink for your teeth and mouth. The three pints produced by the salivary glands each day contain antibacterial substances that protect teeth from cavities. Like all body fluids, saliva is a near cousin to blood, so it contains calcium and phosphorus that teeth absorb. It also functions as an overall lubricant for the mouth, preventing food from sticking to your teeth and gums. By neutralizing gastric acid and keeping the flow of food and drink through the mouth and esophagus on the right course, saliva may help check gastro-esophageal reflux, a leading of cause of heartburn. A serious lack of saliva -- the medical term is xerostomia (pronounced zer-o-STO'-me-ah) -- may develop for several reasons. It's a side effect of many medications. It may result from autoimmune diseases such as lupus and Sjögren's syndrome. Head and neck cancer patients struggle with dry mouth after receiving radiation treatments. Dry mouth is another reason you should see a dentist regularly. During a routine exam, dentists are supposed to look for little pools of saliva in the bottom of the mouth. The inside of your salivary glands are there, so dryness there is a bad sign. The treatment depends on the cause and its severity. Doctors and dentists no longer believe that old age by itself causes clinically significant dry mouth. But salivary glands do tend to become less productive with [...]