re the amount of this huge excess - as could ever contact the surface-area of all teeth. Y'know? I'm missing this point.How do all detergents (soap, dish-washing stuff, laundry detergent, etc etc) work? I thought it was chemically -- the dirt (or, in this case, the bacteria) binds to the detergent, in stead of whatever surface it is presently adhering to, right? But... once that's happened, what good is that particular detergent molecule? Nothing, AFAICS; it's "spent", bound to the dirt it's picked up already.
So I assumed he meant this is what happens; all the detergent in your tiny dollop of toothpaste is bound to just part of the bacteria: Brushing on after that does no good, except for pure mechanical abrasion; you could just as well brush with just pure water. It's not just about covering a *surface* (cf your "contact the surface-area"); it must also be about how *thick* the layer of dirt on that surface is.
Then again, this is just *my* interpretation of his point; I'm not saying fersure that's how *he* meant it works. YMMV. (But mine's lower! :-)