I have nothing against dentists, endodontists etc.. But before I was diagnosed I was run around to for at least a month. Dentist to the endodontist to the periodontist back to the dentist and endodontist before I saw an oral surgeon. If you don't feel comfortable with them I would go see a maxillofacial oral surgeon as they have more experience with oral cancer and that might ease your mind a little more.

I hope you are able to get some resolution soon as I know how trying it can be do go round and round before someone figures it out.