The inside of your mouth is lined with three pairs of salivary glands -- the sublingual, submandibular and parotid glands. There are also hundreds of tiny ones tucked under the lining of your mouth, which makes it all the more baffling if you often wake up with a very dry mouth. Part of the reason for this is that you don't produce saliva when you're sleeping, but other factors also contribute to morning dry mouth. Fortunately, dry mouth causes can be simple to counteract.
The saliva in your mouth keeps your tongue moist and agile so that you can form words, and also moistens food, making it easier to swallow. The three pints or so of saliva you produce every day contains antibacterial properties that guard against infections. It also helps protect your tooth enamel from acidic foods and aids in breaking down starchy foods so that you can digest them.
Dry mouth, or xerostomia, can be caused by snoring. Regular snoring that is not caused by sleep apnea is caused by an obstruction to your upper airway, which causes you to open your mouth. Since you don't produce saliva when you're sleeping, the air moving in and out as you snore dries out the mucus membranes lining the inside of your mouth. Rinsing your mouth or drinking water when you wake up will alleviate dry mouth caused by snoring.
Sleep apnea causes you to stop breathing for a short time while you're asleep. In the most common type, obstructive sleep apnea, your throat muscles relax so much that your airway gets blocked. The more serious type of sleep apnea, central sleep apnea, happens when the signals that go from your brain to your breathing apparatus aren't right. Some people have a third type, called complex sleep apnea, which is a combination of the first two. In all cases, one of the symptoms is dry mouth. Central and complex sleep apneas are serious conditions that can be diagnosed through tests, so if you are waking up with a dry mouth and sore throat, you should consult your physician.
Certain medications can also cause dry mouth, both at night and during the day. Non-prescription cough and flu medicines, cold remedies, decongestants and antihistamines can cause dry mouth. Prescription analgesics and drugs that treat nausea, depression and anxiety contain ingredients that can cause dryness. Radiation and chemotherapy for cancer can also make your mouth dry.
There are several causes of dry mouth at night that are purely physical. Aging can slow the production of saliva, as can certain cancers. One of the first symptoms of both diabetes and Sjogren's Syndrome is dry mouth, and nerve damage can also cause this condition.
Treatments and Cures
It isn't possible to treat or cure dry mouth at night until you know what is causing it. Unless you're absolutely certain that the cause is snoring, a short-term medication or simply sleeping with your mouth open, you should consult your physician.