Preface: Update of Dental Local Anesthesia Paul A. Moore, Elliot V. Hersh, and Sean G. Boynes

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1 Update of Dental Local Anesthesia Preface: Update of Dental Local Anesthesia Paul A. Moore, Elliot V. Hersh, and Sean G. Boynes xiii Local Anesthetics: Pharmacology and Toxicity 587 Paul A. Moore and Elliot V. Hersh The development of safe and effective local anesthetic agents has possibly been the most important advancement in dental science to occur in the last century. The agents currently available in dentistry are extremely safe and fulfill most of the characteristics of an ideal local anesthetic. These local anesthetic agents can be administered with minimal tissue irritation and with little likelihood of inducing allergic reactions. A variety of agents are available that provide rapid onset and adequate duration of surgical anesthesia. This introductory article provides a brief update of the clinical pharmacology of local anesthetic agents and formulations used in dentistry at present. The Use of Local Anesthetic Agents in Medicine 601 Steven Ganzberg and Kyle J. Kramer Local anesthetics are commonly used in both dentistry and medicine. These drugs are also used in some office-based medical practices. Except for minor procedures, most physicians who require complicated nerve blocks rely on anesthesiologists to administer the local anesthesia. Both ester and amide local anesthetics are routinely used in medical practice. This article reviews the types and uses of local anesthesia in anesthesiology. Long-Acting Local Anesthetics and Perioperative Pain Management 611 Sharon M. Gordon, Anastasia V. Mischenko, and Raymond A. Dionne Although the use of long-acting local anesthetics has become a useful therapeutic approach for managing peri- and postoperative pain, recent evidence reveals unexpected outcomes. This article reviews the clinical use of long-acting local anesthetics, presents current clinical research findings, and makes recommendations for their use. Infiltration Anesthesia in the Mandible 621 John G. Meechan Infiltration is preferred to regional block techniques in the maxilla as the former offers a number of advantages. This paper considers the evidence for the efficacy of infiltration anesthesia in the mandible in the adult dentition, both as a primary and as a supplemental method. Phentolamine Mesylate foraccelerating Recovery from Lip and Tongue Anesthesia 631 Elliot V. Hersh and Rochelle G. Lindemeyer Phentolamine mesylate, at dosages from 0.4 to 0.8 mg in adults and adolescents and at dosages from 0.2 to 0.4 mg in children aged 4 to 11 years,

2 viii has been proven to be safe and effective for the reversal of soft tissue anesthesia (lip and tongue numbness) and the associated functional deficits resulting from a local dental anesthetic injection containing a vasoconstrictor. Its ability to block a-adrenergic receptors on blood vessels induces vasodilation and enhances the redistribution of the local anesthetic away from the injection site. The low dosages administered for dental local anesthetic reversal in all likelihood accounts for the lack of significant cardiovascular effects that are associated with the medical use of the drug for hypertensive conditions associated with catecholamine excess. Efficacy of Articaine Formulations: Quantitative Reviews 643 Kellie Paxton and David E. Thome In 2000, the US Food and Drug Administration (FDA) approved the use of 4% articaine with epinephrine 1:100,000, and with epinephrine 1:200,000 in Articaine has been commonly compared with its predecessor, lidocaine hydrochloride. Since its introduction in 1948, lidocaine has maintained a status as the most widely used local dental anesthetic in most countries. Proven efficacy with low allergenicity and toxicity over longterm clinical use and research have confirmed the value and safety of this drug. Thus, it became the gold standard to which all new local anesthetics are compared. Despite the gold standard status of lidocaine, numerous reports and editorials have supported and recognized the use of articaine. Allergic Reactions to Local Anesthetic Formulations 655 Steven J. Speca, Sean G. Boynes, and Michael A. Cuddy True allergic reactions to local anesthetics are rare adverse reactions. At the most, they represent less than 1% of all adverse local anesthetic reactions. When true allergic reactions have been confirmed, the reactions are most commonly the type I anaphylactic and type IV delayed hypersensitivity responses. The type I immediate hypersensitivity reactions are the most severe and may be life-threatening. In the event a potential allergic reaction occurs in a dental office, the dentist needs to properly evaluate the events leading up to the reaction and provide a differential diagnosis. A referral should be given to any patient when an allergic reaction cannot be ruled out as an intravascular injection, toxic overdose, psychogenic reaction, or an idiosyncratic event. Acquired Methemoglobinemia Revisited 665 Larry Trapp and John Will Dentistry has two medications in its pain management armamentarium that may cause the potentially life-threatening disorder methemoglobinemia. The first medications are the topical local anesthetics benzocaine and prilocaine. The second medication is the injectable local anesthetic prilocaine. Acquired methemoglobinemia remains a source of morbidity and mortality in dental and medical patients despite the fact that it is better understood now than it was even a decade ago. It is in the interest of all

3 ix dental patients that their treating dentists review this disorder. The safety of dental patients mandates professional awareness. Ocular Complications Associated with Local Anesthesia Administration in Dentistry 677 Sean G. Boynes, Zydnia Echeverria, and Mohammad Abdulwahab The most widely used method for controlling pain during dental procedures is the intraoral administration of local anesthetics in close proximity to a specific nerve or fiber to obtund nerve conduction. The most commonly anesthetized nerves in dentistry are branches or nerve trunks associated with the maxillary and mandibular divisions of the trigeminal nerve (cranial nerve V). However, other nerves may be inadvertently affected by intraoral local anesthesia injections, resulting in anesthetic complications of structures far from the oral cavity. Practitioners should be aware of potential ocular complications following intraoral injections in dentistry. These complications include oculomotor paralysis and vision loss. The knowledge of these conditions and their potential cause should alert the dentist to the importance of appropriate injection techniques and an understanding of management protocol. Beta-adrenergic Blocking Agents and Dental Vasoconstrictors 687 Elliot V. Hersh and Helen Giannakopoulos A clinically significant interaction between epinephrine or levonordefrin with nonselective beta-adrenergic blocking agents, although apparently rare in the dental setting, is potentially serious and can lead to significant hypertension with a concomitant reflex bradycardia. Based on the results of epinephrine infusion studies, the severity of the interaction seems dose related; small epinephrine doses cause less of a pressor response than larger doses. The interaction can be seen after intraoral submucosal injections but is generally of a smaller magnitude, at least with only 1 or 2 cartridges of lidocaine plus 1:100,000 epinephrine. However as demonstrated by 1 case report, some individuals are hypersensitive to this interaction. Inadvertent intravascular injections of local anesthetic plus vasoconstrictor and the use of high doses of vasoconstrictor are likely to result in a more pronounced response. Patients with significant cardiovascular disease may be especially vulnerable to the most serious sequelae resulting from the pressor reactions of the drug combination. Local Anesthetic Use in the Pregnant and Postpartum Patient 697 Edgar P. Fayans, Hunter R. Stuart, David Carsten, Quen Ly, and Hanna Kim The use of systemically absorbed drugs in the gravid and in the lactating patient is of concern to the dentist. This article reviews concerns for the health and safety of the mother, developing fetus, and neonate involving local anesthetics. The available literature on the use of local anesthetics for dentistry in the pregnant and postpartum patient is also reviewed. In addition, the physiology of the pregnant and postpartum woman is

4 x discussed because this is essential to understanding potential interplay with local anesthesia and the stress of a dental appointment. Paresthesias in Dentistry 715 Paul A. Moore and Daniel A. Haas Alterations to normal oral sensory function can occur following restorative and surgical dental procedures. Paresthesia is defined as an abnormal sensation, such as burning, pricking, tickling, or tingling. Paresthesias are one of the more general groupings of nerve disorders known as neuropathies. This article reviews the extent of this oral complication as it relates to dental and surgical procedures, with specific emphasis on paresthesias associated with local anesthesia administration. This review establishes a working definition for paresthesia as it relates to surgical trauma and local anesthesia administration, describes the potential causes for paresthesia in dentistry, assesses the incidence of paresthesias associated with surgery and local anesthesia administration, addresses the strengths and weaknesses in research findings, and presents recommendations for the use of local anesthetics in clinical practice. Needle Phobia: Etiology, Adverse Consequences, and Patient Management 731 Chester J. Sokolowski, Joseph A. Giovannitti Jr, and Sean G. Boynes Needle phobia has profound health, dental, societal, and legal implications, and severe psychological, social, and physiologic consequences. There is genetic evidence for the physiologic response to needle puncture, and a significant familial psychological component, showing evidence of inheritance. Needle phobia is also a learned behavior. The dental practitioner must recognize patients with needle phobia before the administration of local anesthetics to identify patients who are potentially reactive and to prevent untoward sequelae. Needle phobia is highly associated with avoidance behavior, and the dentist must exhibit compassion and respect. To avoid bradycardia, hypotension, unconsciousness, convulsions, and possibly asystole, oral premedication with benzodiazepines or other antianxiety agents must be considered for patients who are needle phobic. Management of needle phobiaeinduced syncope includes perioperative monitoring, oxygen administration, positioning, atropine, and vasopressors. Needle Breakage: Incidence and Prevention 745 Stanley F. Malamed, Kenneth Reed, and Susan Poorsattar Since the introduction of nonreusable, stainless steel dental local anesthetic needles, needle breakage has become an extremely rare complication of dental local anesthetic injections. But although rare, dental needle breakage can, and does, occur. Review of the literature and personal experience brings into focus several commonalities which, when avoided, can minimize the risk of needle breakage with the fragment being retained from occurring.

5 xi Advanced Techniques and Armamentarium for Dental Local Anesthesia 757 Taylor M. Clark and John A. Yagiela Computer-controlled local anesthetic delivery (C-CLAD) devices and systems for intraosseous (IO) injection are important additions to the dental anesthesia armamentarium. C-CLAD using slow infusion rates can significantly reduce the discomfort of local anesthetic infusion, especially in palatal tissues, and facilitate palatal approaches to pulpal nerve block that find special use in cosmetic dentistry, periodontal therapy, and pediatric dentistry. Anesthesia of single teeth can be obtained using either C-CLAD intraligamentary injections or IO injections. Supplementary IO anesthesia is particularly suited for providing effective pain control of teeth diagnosed with irreversible pulpitis. Local Anesthesia Administration by Dental Hygienists 769 Sean G. Boynes, Jayme Zovko, and Robert M. Peskin Within the last 30 years, the role of dental hygienists has expanded to include the administration of local anesthesia. Several studies have been performed to assess practice characteristics and effectiveness of these changes in state licensure regulations. Findings indicate an acceptance of this expansion in dental hygiene practice; however, the delegation of this pain control procedures remains controversial. To address this controversy, the authors have reviewed of current literature to assess the practice of local anesthesia administration by dental hygienists. Index 779