Abstract: A fluid delivery system for a dental cleaning appliance includes a nozzle for delivering a burst of working fluid to the teeth of a user, and a fluid conduit for conveying working fluid to the nozzle. A body of the nozzle defines a fluid chamber and a channel for conveying working fluid from the fluid chamber to a fluid outlet from the nozzle. The fluid chamber has a tangential inlet for receiving working fluid from the fluid conduit.

Abstract: A polyphosphate-based glass scale inhibition composition comprising from about 45 to about 55 mole percent P2O5, from about 35 to about 45 mole percent of an oxide of an alkaline earth metal, and from about 8 to about 12 mole percent of an oxide of an alkali metal.

Abstract: A fluid delivery system for a dental cleaning appliance includes a nozzle for delivering a burst of working fluid to the teeth of a user, and a fluid conduit for conveying working fluid to the nozzle. A body of the nozzle defines a fluid chamber and a channel for conveying working fluid from the fluid chamber to a fluid outlet from the nozzle. The fluid chamber has a tangential inlet for receiving working fluid from the fluid conduit.

Abstract: A dental cleaning appliance includes a nozzle having a fluid chamber, a fluid outlet and a channel extending between the fluid chamber and the fluid outlet. A water reservoir provides water to a pump for generating a burst of pressurized water, which is supplied to the nozzle by a fluid conduit. Following the delivery of the burst of water to the teeth of the user, a valve draws water back into the fluid chamber from the channel to prevent that water from dripping from the fluid outlet before the next water burst is generated by the pump. Simultaneously, air may be drawn into the fluid chamber, for example, through the fluid outlet, for mixing with the next water burst to generate a fluid burst for delivery to the user's teeth.

Abstract: The invention provides a water feature comprising a vessel containing a volume of water and means for imparting rotational motion thereto, wherein means are also provided for varying the height of the volume of water in the vessel. The invention also provides a method of operating a water feature comprising at least one vessel containing a volume of water, comprising the steps of causing the or a volume of water to rotate about an axis thereof so as to form a vortex therein and causing the rotating volume of water to vary in height over time.