What Causes Recurrent Vestibular Migraine?

Hi. I get vestibular migraines and sometimes when I go to dentist, it can trigger off and then I have trouble with balance for awhile. I have to have a premolar pulled and a temporary bridge put in, a procedure that should take about 1 hour or more. I have had crowns down before since I developed this problem and sometimes I have no trouble. At first I thought it was the number of needles I got of the lidocaine, maybe a sensitivity to it, but my dentist says no, it is most likely the position I was in plus the fact I had a slight headache already, probably due to spring allergy sensitivities. Anyway, I saw the Dr. at Johns Hopkin's last week who diagnosed me with the vestibular migraines and said that yes, position can trigger it. His suggestion was to take Topamax, but as this drug is pretty strong and an anti-seizure drug with tons of side effects, I am not willing to try that one and being he is not a neurologist, he is an ear doctor, I decided to just keep doing what I have been doing and see the neurologist for other option. I guess being tense and already having a slight headache could have triggered the vestibular migraine. My dentist is going to keep me more upright, when I go in to do this, and since I now know it is not the anesthetic doing it, I may be more relaxed, however do you think if I took advil before I go, since it does keep vessels from closing up, it will help prevent migraine from triggering.