Patent ID: 7211220

Claim:
A method for cleaning and disinfecting or sterilizing the water circuits ( 1 ) of dental units ( 100 ), where the water circuit ( 1 ) of the dental unit ( 100 ) comprises a main conduit ( 2 ) for supplying a user fluid from a mains supply ( 7 ) to a plurality of branches ( 3 ) equipped with shutoff means ( 5 ), said plurality of branches ( 3 ) for supplying corresponding medical instruments ( 4 ) having endpieces ( 3 a ), the method comprising: introducing a cleaning and disinfecting or sterilizing fluid into the water circuit ( 1 ); holding the cleaning and disinfecting or sterilizing fluid in the water circuit ( 1 ) for a predetermined length of time; and draining the cleaning and disinfecting or sterilizing fluid out of the circuit ( 1 ) through endpieces ( 3 a ) of the supply branches ( 3 ); wherein the method further comprises a step of programming a contact time period T for the combined steps of introducing and holding the fluid in the water circuit ( 1 ) according to a desired parameter level of cleaning and disinfecting or sterilizing andlor of predetermined or predeterminable events on the dental unit ( 100 ), this step preceding the step of introducing the fluid and including selecting T from a plurality of contact time periods T 1 , T 2 , T 3 , . . . Tn, wherein each contact time period T is defined by the equation T =[(Ta−K)+Tb], and wherein Ta is defined as the time period of the step of introducing the fluid in the water circuit ( 1 ), K is a constant filling time during which the surfaces of the water circuit ( 1 ) cannot be considered to be in contact with the cleaning and disinfecting or sterilizing fluid, and Tb is defined as the time period of the holding step.