A dental appliance having a passive arrangement for drawing liquid from a reservoir (22, 33, 54) in the appliance by action of a stream of gas, which can be provided by a source of compressed gas (31, 34) or other system. The liquid mixes with the gas, resulting in liquid droplets which are directed through an orifice (18, 42, 68) at the end of a nozzle portion (12, 39, 66) of the appliance.