still really curious if the "toothache" symptom relates directly to nasal route and corrosive nature
a subconscious reason i pushed with this chemical was..
i had orbital eye surgery which had to involve the left sinus and nasal
wasn't a recent surgery but interested in potential and damage, not specifically for my own case
If it's an acute tooth pain (occurring immediately after insufflation) then I think it's due to the way the nerve supply in your face is stuctured. The maxillary nerve covers sensation for most of the nasal cavity, but it also covers the upper teeth, the cheek overlying the maxillary sinus, the paranasal sinuses themselves and the lower eyelid. I often get referred pain, which is pain felt somewhere other than the site of the stimulus, so my teeth hurt if I insufflate something painful (inc the 2C-x drugs.) The pain can linger for several hours sometimes as a dull ache in my upper teeth, long after my nose has stopped hurting.. and it can be a lot more painful than my nose is! My eye also streams with tears (out of proportion to the pain) and the maxillary nerve makes up part of the nerve supply to your tear ducts.
My teeth also hurt if I get chronic sinusitis, so if you have longer-term tooth pain which you suspect may be caused by ethyphenidate usage I would speculate that you could have an inflammed nasal mucous membrane in the deep part of the nasal cavity, which is causing referred pain.. or a non-infective sinusitis (irritatation and inflammation of the epithelial lining of your sinuses - usually immune-mediated and due to infection or pollen allergy but could potentially be chemical in nature as once inflammation takes hold it can be self-perpetuating). This to me seems far more likely than actual erosion of tissue, and I think if that had happened (would involve erosion not just into your palate, which would cause a hole in the roof of your mouth open to the nasal cavity, but also into the maxillary bone itself and through to the teeth..) you would be experiencing more than just some toothache. An eroded septum could realistically cause referred tooth pain as the main symptom though, so certainly worth ruling that out.
Of course, get your teeth checked if you have toothache post-insufflation, but if that fails and the pain is severe/persistent it could be worth getting an Ear, Nose and Throat doc to have a proper look at your nasal caity and sinuses (they can do this with an endoscope - flexible tube with a camera on the end). You don't want to end up like Daniella Westbrook! (Although cocaine mostly caused gangrenous damage through local vasoconstriction, ethylphenidate seems actually corrosive/irritant seeing as people have noticed bleeding.. with added vasoconstriction to impair healing

All in all, sounds like insufflated eph is something to avoid. If you do insufflate it, take the excellent advice of others on here and use a solution, squirting water up afterwards to wash any residue away, and get any persistent pain checked out! Even the temporary referred maxillary tooth pain was too much for me to try again snorting the stuff... plugging was the way forward, before I gave up on it altogether.