Evaluation of an Electro-stimulator for the Treatment of Xerostomia

This is a multinational trial, aimed at testing the safety and performance of a electrostimulating device (\"GenNarino\") to treat dry mouth, over one year. The design is as follows: * Multi-center, double blind, sham (placebo) controlled, about 10 xerostomia patients per center * Patients receive a GenNarino (and its remote control) that is programmed for one month sham and one month active mode (the order of which is randomly assigned), and thereafter 9 months at the active mode (divided in period of 3 months, the order of each is randomly assigned at wearing GenNarino for 1, 5 or 10 minutes at a time). Study hypothesis: Gennarino will lead to significant symptomatic improvement - At the clinic: monthly examinations at the first 2 months, and then every 3 months, including whole saliva collection and questionnaire; at the first visit impression taking for GenNarino preparation