Questions & Answers about Tengo un dolor de muelas terrible.
Why does this use muelas instead of dientes for "teeth"?
While dientes is the general word for teeth, muelas specifically refers to your molars. In Spanish, a toothache is almost always called un dolor de muelas, even if it is a front tooth that actually hurts.
Can I use the verb doler (to hurt) to express this instead?
Why is terrible at the very end if it describes the pain (dolor) and not the teeth (muelas)?
The phrase dolor de muelas acts as a single concept (toothache). Since descriptive adjectives usually follow the noun they modify in Spanish, terrible goes after the entire block to describe the ache as a whole.