A prophylactic system 100 for a dental hand piece 101 of a selected shape and having an outlet 112 for providing a fluid to an operating field is disclosed. A cover 102 has a shape substantially similar to the hand piece 101 for enclosing the dental hand piece 101 and includes an aperture 118 for communicating with the operating field. An s-shaped valve 600 includes a path 605 for coupling the fluid from outlet 118 of the hand piece 101 to the aperture 118 of the cover.
