A viscous material dispensing system 100 utilizes pressurized gas directed to one end of a piston 109 and cylinder 103 assembly to extrude impression material 128, 129 from a dispenser 121 through a tube 133 into a dental tray 135 which hardens to form a mold of the patient’s mouth. The device includes a main board, an intermediate board, and electrical connection balls in a space separating the boards. The switch has a first switch contact and a second switch contact, which are connected in parallel in the electric circuit.