All currant cancer therapies are hard on the immune system in general and many can create a dry mouth. Excellent nutrition and lots of water is of utmost importance throughout the process. Excellent homecare habits and regular professional supervision, which may include fluorides, is mandatory during these times. Radiation therapy in the head and neck area often destroys salivary function and a saliva replacement must be used regularly. Many cancer patients undergo a recurrent bout of root decay as the immune system declines.