> Our modern culture taboos anything less than brushing multiple times per day, but it’s not clear how reliable the evidence is supporting this as a blanket requirement (the studies I’ve seen had many other confounding variables, but admittedly I did not do an exhaustive literature review), and most of the tooth infections probably result from other causes.

I've heard so much conflicting information on this... Off the top of my head:

* Brushing too often - such as three times a day - speeds up erosion

* Or, that only happens if you brush too hard

* Or, that brushing too hard doesn't affect the teeth, that that's just confusion with it affecting the gums

* Or, that it has nothing to do with duration or hardness, but rather, how soon after eating that you brush (something about the extra saliva for food causing a slight weakness that takes an hour or so to go back to normal)

* Or, that leaving food residue in the mouth for any duration - such as that hour in the last case - causes saliva and bacteria buildup that speeds up erosion