amounts of air and liquid are mixed and a foam capable of maintaining its structure for a substantial length of time is dispensed in addition the dispenser can deliver a variable amount of foam so as to just fit a variable size of toothbrush the f 2 finger pump foamer u2122 is similar in design and operation to conventional propellant less finger actuated mechanical pump foamers such as described in u s pat no 5 443 569 issued on aug 22 1995 and u s pat no 5 813 576 issued sep 29 1998 the disclosure of which are incorporated by reference herein such propellantless finger actuated mechanical foamers can be employed to dispense the stable dentifrice foam of the present invention the f 2 finger pump foamer u2122 is an easy to use dispenser with excellent performance and provides a clean single stroke action zero voc formulations and high quality shaking the container will not affect the foam quality precise dosage per stroke is possible and the container is refillable 1 fumed silicon dioxide aerosil 200 u00ae degussa 2 000 2 fumed aluminum oxide alum c u00ae degussa 2 000 3 amorphous synthetic ppt silica sident u00ae degussa 6 000 4 sorbo.