A dental cleaning appliance has a fluid reservoir 34 for storing working fluid for delivery as bursts of fluid to the teeth of a user. For viewing and assessing the amount of fluid left in the reservoir, the reservoir is at least partially delimited by a transparent external wall 110 and a reservoir wall such as a diaphragm 118 which is moveable relative to the external wall to vary the volume of the fluid reservoir. Part of the appliance, preferably the elastomeric diaphragm 118, may be formed from a photochromic material which changes colour when exposed to ultraviolet UV radiation, for example within a sterilization chamber, to indicate when sterilization has been performed or is due.
