Hello and welcome!
Not always, but sometimes, it's more an internal issue rather than a dental one that causes bad breath.
It hasn't happened with Harry (he loves RC and it suits him) but one of my previous dogs had really, really stinky breath. We had all the work done on her, teeth were perfect - but it was suggested that we change her food, which we did....and the problem was solved within a couple of weeks
Just wondering, how are her poops - and is she gassy at all?