Table 1 Inclusion and exclusion criteria

• Patients with oncologic diseases of the head and neck area, and implemented radiotherapy of the head and neck area

• Men and women at the age of at least 18 years

• Unstimulated saliva flow rate < 0.1 ml/ min

• Patient's education and written approval of the participation before enrollment

• Good prognosis of life expectancy

• No paraben allergy

• Willingness to co-operate (compliance) of the patient

• Ability and willingness to return for follow-up visits

• No participation in other study (3 months before and) during the participation

• Pregnancy and lactation period

• HIV-infection

• Hepatitis B/C virus infection

• Reluctance for the storage and disclosure of personal disease data in the context of the study plan

• No written approval

• Paraben allergy

• Concurrent participation in another clinical study

• Persons who are accommodated on account of official or judicial arrangement in an institution (§40 Abs.1 S.3 Nr.4 AMG)

• Patients who do not wear their dentures at night

• Known hypersensitivity to ingredients of Saliva natura and Glandosane (sodium benzoate may cause slight irritation to skin, eyes, and mucous membranes)