Can dental anesthetic/medication lead to a false positive result on a hair drug test?

I have to take a hair drug test for a new job. I am probably just paranoid but i'm concerned that I could test "falsely positive" because I had some dental work done over the last 6 months which included the use of Novocaine (or whatever they use now), Vicoden and Codeine, and antibiotics. now I'm sure this is a common problem, so do most labs double check any positive results to further rule out anything? and would I be able to dispute the results by showing them my dental/medical records?