This study will follow patients with salivary gland dysfunction to identify the long-term course of this disorder and its effects on the mouth, oral function, and overall health. Saliva is important in maintaining oral health and comfort. It moistens the mouth, lubricates food for easier swallowing, provides enzymes needed to begin the digestive process and promotes repair and cleansing of soft tissues of the mouth. Decreased salivary production or changes in salivary composition may affect oral and systemic health and cause an increase in tooth decay.