A device (10) having a body (12) formed from as a one-piece single unit having a first tray portion (16) for receiving the upper dental arch of the oral cavity of the wearer and a second tray portion (14) for receiving the lower dental arch of the oral cavity of the wearer. Integrally formed therewith and connecting the two tray portions are two connecting portions (18), (20) which are flexible and the two tray sections are of a design or material or combination of design and material selected to achieve retention of the trays on the teeth of a user.
