A New Oral salIvary equivAlent Compared to Two moisturizinG Mouth sprAys in Patients With xeRostomiA: NIAGARA Study

Inclusion Criteria:

Patients:

* Aged 18 years or more,
* Clinical diagnosis of xerostomia by a severe reduction of salivation, as detected by patient's answers to few specific questions and measured by saliva volume at screening visit (test of saliva weight absorbed ≤ 0.1g/min)
* Any medical condition or treatment leading to a severe reduction of salivation related to either:
* Head and neck radiation therapy for cancer,
* Gougerot-Sjögren syndrome
* Medications known to induce xerostomia (psychotropic drugs, antihypertensive drugs)
* Dehydration, hypothyroidism, Parkinson's disease and/or diabetes mellitus
* Female patients must be post-menopausal or using a highly effective method for avoidance of pregnancy throughout the whole study duration, if childbearing potential.
* Able to understand and comply with the protocol procedures
* Willing and able to give their written informed consent
* Affiliated to the French National Health Insurance Program

Exclusion Criteria:

* Known hypersensitivity to one of the study products or to one of their components
* Any planned change in dosing of all known medications inducing mouth dryness
* Concomitant treatment for xerostomia symptoms without a scheduled 3 to 7-day withdrawal window
* Oral candidiasis as diagnosed by a microbiological test obtained from an unstimulated whole saliva sample until 3-week period from disease release
* Oral ulceration
* Alcohol (\>2 glasses of wine/day), smoking (\>10 cigarettes/day), caffeine and/or theine intake (\>4 cups/day)
* Patients unable to fill out the questionnaires or to comply with the study protocol
* Dental infection
* Patients participating to another clinical trial at the time of the study entry or within 30 days prior to study enrolment
* Life-threatening condition at the time of the study
* Pregnant or lactating women and women of childbearing potential refusing to use adequate contraception.