Question: A patient reports to the ED complaining of a severe toothache. The physician finds a tender molar in the lower half of the mouth. She performs a dental block on the patient and sends him home. What is the best code for the block? Michigan Subscriber Answer: It depends on which part of the mouth the physician injects. There are a pair of codes to represent dental blocks: - 64400 (Injection, anesthetic agent; trigeminal nerve, any division or branch) for blocks on the trigeminal nerve - 64450 (- other peripheral nerve or branch ) for blocks on any peripheral nerve or branch. So if the notes indicate that the physician injected the trigeminal nerve, report the following: - 64400 for the block - 525.9 (Unspecified disorder of the teeth and supporting structures) appended to 64400 and 99282 to represent the patient's injury.