Question: A patient presents in the ED with a toothache. The ED physician performs a nerve block. Is 64402 the correct code to report for this case? New Jersey Subscriber Answer: No, for the dental nerve block you should report 64400* (Injection, anesthetic agent; trigeminal nerve, any division or branch). The mandibular nerve is a branch of the trigeminal nerve, not the facial nerve. So don't use 64402* ( facial nerve) for this procedure.