Reading this thread, it does sound SO much like my Alfie. His agression suddenly increased over a week or so, and we could "tell" he was in pain, even though 2 vets told us it was behavioural problems (which there are too, to be fair to them, but we knew they werent the cause of this sudden increase)
A few weeks on the painkillers has seen an enormous reduction in his agression, although it will still flare up if he overdoes it on a walk, or gets too carried away with his playfighting with Purdey. Generally he is a different dog. Tomorrow we are taking him back to the vets for our "1 month on" check up so hopefully now he will be able to see the painkillers have made, he will look harder at the physical problems, which I am pretty sure are related to his dodgy knee ligament!
I really hope that the tooth problem is the answer and that you continue to see a change in your gorgeous girl.