Patient Female, 45 year old. Chief Complaint While eating, she bit down on something hard and immediately experienced a sharp shooting pain on the left side that persisted even after she

stopped chewing. She had increased sensitivity in her lower left molar to hot and cold foods or drinks. Background and/or Patient History The patient had been in your office for many years and practiced good oral hygiene and reported annually for examination and prophylactic cleaning. Current Findings Upon examination you diagnosed a crack in the dental restoration in the lower left first. Case I. Local Anesthesia for Controlling Dental Pain. Understanding why your local anesthetic is "smart enough" to know how to block the pain efficiently and selectively Drs. H. Cohen and R. Shirokov. Images are courtesy of Dr. P. Duda Cook-Walte Lidocaine HCI 2% and Epinephrine 1:100,000 Injection (lidocaine hydrochloride and epinephrine injection, USP) Marked by Canestream Heath, inc To block the pain in the lower left molar, you injected the left inferior alveolar nerve with a cartridge of 2% lidocaine/epinephrine 1:100,000. After several minutes she reported the area was "numb" and that she had no feeling of the previous pain. She was able to open her mouth and position her jaw so you could complete her tooth restoration with no difficulty. 1. The patient felt numb but could touch and feel her face, teeth, and mouth after she was injected. Describe the basic neuron anatomy and physiology of how these impulse sensations are conducted along the nerve fiber. a) What types of nerve fibers are involved affecting her tooth pain and other aspects, such as sensitivity to touch and jaw movement? b) How are action potentials conducted through these fibers? Describe the differences. c) What are the principal factors determining conduction velocity in different types of nerve fibers?