Total thirst and dry mouth are usually seen in the dentist because of a clinical symptom, but there are many thirst-related disorders that can be resolved by more than just the dentist. Significant thirst and dry mouth symptoms are called Sjögren’s Syndrome, which is also known as Desiccation Syndrome. This is an immune system disorder characterized by dry mouth, dry eyes, swollen glands, and joint pain. Dry mouth can also occur in diabetes, hyperthyroidism, and other such systemic diseases. If there has been a malignant tumor, such as nasopharyngeal cancer, radiation therapy is also an obvious cause of dry mouth. In stomatology dry mouth, often cause a variety of diseases of the oral cavity, especially the whole mouth caries, because the mouth is dry, there is no saliva fluidity of cleaning, will cause caries serious growth, so the dry mouth in addition to clarify the cause of the disease, the same should be done to better oral maintenance.