Comparing frontal lobotomies (FLs) with cavity fillings is not an appropriate comparison, IMHO. FLs were always quite controversial because of the serious impairment side-effects and the danger inherent in the procedure (5% death rate during procedure). The operation caused serious brain damage to most - that was its modus operandi.

On the other hand, drilling holes in teeth seems like a low-tech solution (though I suppose that humans from years past would view it as a marked improvement from tooth-pulling), but it ultimately gets the job done, more or less, with minimal negative side-effects.