Dental Anesthetic Question?

I took a 10 panel hair test to prove that I was on a prescribed medication and the test came back positive for that medication but it also came back positive for cocaine. I DO NOT DO DRUGS. I have been going to the dentist weekly (sometimes twice a week) from January 2011-last week and getting the following injections (multiple injections each week) of 2%Lidocaine with epinephrine 1:100,000 0.5% Marcaine (Bupivacaine HCl with 1:200,000 epinepheine) and Diflunisal 500mg (NSAID) I have a letter proving the above but the MRO wants proof that these could produce a positive cocaine result. They will accept information from an AMA journal article or qualified physician.