The trusted dentist’s recommendation is classic canon in the toothpaste ad sales game. Sometimes, a voiceover tells us that nine out of 10 dentists prefer a certain toothpaste . Other times, a white-coated “dentist” (who may or may not be an actor) explains why a particular paste is the only one good enough for his or her own teeth. Either way, we never really know what dentists like best. It’s a worthy question that we even neglect to ask at our own dental appointments , as we become so overwhelmed by what’s about to go down in the chair that all logical inquiries go out the window.