This is an important word. I don't deny that. If it didn't exist then doctors would have to coin a word that meant the same thing.
Both bits of the word are impeccably Greek, too: it's not a lumpy Greek/Latin hybrid like, say, the word television*.
And it's easy enough to pronounce.
So what's wrong with it?
Well, the fact that it doesn't mean to do with the stomach, as anyone might think, but to do with the mouth.
photo by Donarreiskoffer
It's all very well the doctors showing off their Greek, but, good grief, it would have been nice if all that medical lot had noticed that most of us have been talking English for a while, here.
Word Not To Use Today: stomatology. Stoma means mouth in Ancient Greek. The logy bit comes from the Greek logos, which means word.
*Not that I have any objection in practice to hybrid words. I mean, in the case of television, an all-Greek version might have given us telescope, which would have been confusing. Though I suppose an all-Latin version, perhaps something like longivision, would have worked.
Actually, I quite like longivision.