Prolong dry mouth can start to cause dental issues like bad breath, periodontitis, and dental decay. Certain medications such as chemotherapy drugs to treat cancer are linked to dry mouth. However, the most common culprits as far as drugs are antihistamines and anti-depressants. If your prescriptions are causing dry mouth, talk to your doctor about swapping to another. In addition make sure to see your dentist regularly to prevent dental damage due to dry mouth.