Breathing through the mouth
There are many causes of dry mouth. The main cause is breathing while your mouth is open. The use of orthodontic appliances such as dental retainers and bite splinters may cause you to breathe through the mouth at night thus causing dry mouth. Breathing difficulties, snoring as well as the use of CPAP masks can cause you to breathe through your mouth.
There are many over the counter and prescribed drugs that cause dry mouth. This is the side effect of many pain relievers and relaxants. Drugs that are consumed by older people have also been found to cause of xerostomia.
Chemotherapy and radiation therapy often lead to dry mouth. This is for the simple fact that these treatments affect mouth glands. These glands can take longer to heal after the treatment. In some cases, radiation has been shown to affect these glands irreversibly.
There are various health conditions that lead to dry mouth. Autoimmune diseases have been found to cause an increase in the frequency of dry mouth.
Chewing or smoking tobacco will cause you to experience dry mouth. This is more so at night. Making some lifestyle changes can help deal away with this problem.