Your dental hygienist just told you that you have Xerostomia (pronounced zero-stomia). Do you panic? Take out a life insurance policy? Start deciding what color teeth you want in your dentures? None of the above. Basically you just learned that you have dry mouth and there are many causes for that.
Xerostomia or dry mouth is caused by a reduction in the amount of saliva manufactured by the salivary glands in your mouth. Saliva is produced to lubricate and moisten the mouth making it easier to speak and swallow food. It provides enzymes to help in the digestion of food and it flushes the bacteria, food particles and dead cells from the mouth. If you aren't producing enough saliva, you may be dehydrated. Not drinking enough water will lead to a decrease in production of saliva. A large number of medications also cause dry mouth. Antihistamines, antidepressants, decongestants, appetite suppressants and muscle relaxants are some of these meds. It is important to drink lots of water to prevent dehydration in the mouth, suck on a sugar free lemon candy to stimulate flow or chew sugar free gum. There are many over the counter products that can help as well.
When the flow of saliva is diminished, plaque and bacteria don't get washed off of the teeth surfaces and the acid produces by the bacteria doesn't get buffered so the risk of cavities is higher. If left untreated, it can be very damaging to the teeth and decay can progress rapidly.
Ask your dentist what products can be helpful to you to treat xerostomia.