Local Anesthetics

Local anesthetics comprise the backbone of pain and anxiety control in dentistry. The pharmaceutical evolution of modern local anesthesia is derived from three significant events in the history of medicine and dentistry, beginning with the applications of cocaine hydrochloride in ophthalmology in the latter part of the nineteenth century and subsequently with the development of the prototypical ester-type agent procaine (Novocain®) in the early twentieth century and the introduction of the prototypical amide-type agent lidocaine (Xylocaine®) in the mid-twentieth century. The pharmacologic characteristics of these drugs are well established, although their mechanisms of action at the subcellular and molecular levels have not been fully elucidated. This chapter will focus on injectable local anesthetics in current use in dentistry, with an emphasis on mechanisms of action, comparative efficacy of key amide agents, and local and systemic toxicity. Coverage of various injection techniques used in dentistry and their relationship to the efficacy of individual agents is beyond the scope of this chapter, and the reader is referred to one of the authoritative textbooks on local anesthesia for information on this area of local anesthesia (Reader et al., Successful local anesthesia, 2nd ed. Quintessence Publishing, Chicago, 2017).