Saliva has an important job to do in your mouth. For starters, it helps to remove food particles. But it also helps prevent tooth decay and infection by washing away plaque and keeping disease-causing bacteria from building up on your teeth and gums. But saliva can’t do all that work by itself. So it’s important to remove plaque yourself by practicing good oral hygiene, which means proper flossing each day, and twice-daily tooth brushing. Most of us don’t think about the moisture in our mouths until our mouths become dry. A variety of conditions can cause dry mouth, also known as xerostomia, including the following: Cancer treatments.  If you have any type of cancer of the head or neck and you receive radiation therapy, dry mouth is a common side effect because the radiation damages the salivary glands in addition to destroying the cancer. Some medications used to treat cancer in any part of the body can also cause dry mouth. Prescription medications.  Hundreds of common ...