The appliance (10, FIG. 1) includes a body portion (27) and a nozzle portion (30) through which a spray of liquid droplets exits from a distal end thereof for cleaning of dental regions. The nozzle includes an orifice (36) at a proximal end thereof adjacent the body portion, as well as a pump (38) for moving liquid into an area of the nozzle just forward of the orifice. A mechanical system (12, 13, 14) is provided for moving a plunger or piston element (16) first away from the orifice under tension, such as a compression spring(24), and then controllably releasing the plunger or piston toward the orifice, the plunger/piston moving with sufficient force that atmospheric air which has been drawn into the appliance between the plunger or piston is forced through the orifice at a sufficiently high rate of speed to produce a spray of fluid droplets for dental cleaning when the moving air comes into contact with the liquid in the nozzle.