When you hear the word Biofilm, it is referring to the micro-organisms that form a film inside your mouth. To put it simply, the mouth is an eco-system, and like all eco-systems, it needs to be balanced keeping the good micro-organisms while getting rid of the bad bacteria.
A balanced mouth has a pH level of 7 which is the way it should be. However, this pH level is altered everyday by sugar, acid, food, medication and dental products. It is necessary to balance your mouth as much as possible.