Abstract: A device is provided to prevent or reduce night clenching and grinding of teeth, as well as to impede snoring. The device is adapted to be placed into a mouth cavity of a patient and includes a conchiform element which is provided with an outer surface adapted to fit into the mouth cavity at an essentially closed position of upper and lower rows of the teeth. The conchiform element is also provided with an inner surface adapted to enclose a tip of a tongue of the patient entirely within the mouth cavity. An extension is adapted to be located under the tongue and has a notched indentation for receiving a ligament of the patient. A retaining element is fixed to the outer surface through a coupling member of a size sufficiently large enough to prevent sucking by the patient.