E R Young’s research while affiliated with University of Toronto and other places

The management of a very anxious patient who had undergone uneventful dental treatment in the past, but posed a problem when clinicians attempted to secure profound mandibular anesthesia, is discussed. This case report also examines the advantages and disadvantages of the Gow-Gates mandibular block technique, and describes the patient's subsequent management.

The development of new local anesthetics has not been an area of particularly active research for a number of years. However, as the use of regional anesthesia has expanded, additional anesthetic requirements and techniques have stimulated the search for newer drugs and ways of modifying existing ones. This article reviews some of the more recent developments in this field.

A case report of an adverse reaction to a preparation of an amide local anesthetic, prilocaine with epinephrine, is presented. Signs and symptoms were consistent with an anaphylactic reaction and the patient responded positively to treatment based on this assumption. Treatment included administration of epinephrine injected sublingually and oxygen by inhalation. However, subsequent skin testing failed to confirm this diagnosis. A number of explanations are possible and a final diagnosis of an anaphylactoid reaction was made. Local anesthetic allergies and their management are reviewed. The literature demonstrates that an allergic reaction to amide local anesthetics can occur and a thorough history, intradermal testing, and subcutaneous challenge are reasonable approaches to determine a safe agent for subsequent use.

Malignant hyperthermia is a potentially fatal disease that may be triggered by the administration of specific drugs or by stress. Although most often associated with general anesthesia, stress can be a significant stimulus and is therefore of concern to the general dentist. The decision as to how and where to treat these patients is complicated by conflicting recommendations from various sources. The aim of this article is to propose a protocol for the dentist to use in the treatment of patients with a history of malignant hyperthermia. The dentist must assess the patient for both their susceptibility to a crisis and the degree of stress of the planned procedure. For non-stressful treatment, it is reasonable to assume that the general dental practitioner can treat these patients in his office. For stressful treatment, advanced preparation is advised.

In the nineteenth century, some natives of Peru noticed circumoral numbness, euphoria and analgesia after chewing the leaves of the Erythroxylen coca bush. By 1850, cocaine was isolated from the plant, marking the start of the local anesthetic era in clinical medicine. Over the past 50 years, many synthetic local anesthetics have been developed which have fewer side effects, increased specificity of action and a wider margin of safety than cocaine. Currently, local anesthetics are used topically, for local infiltration; and intravenously, for peripheral nerve blockade, for sympathetic blockade, as well as for epidural and intrathecal use. Although the route of administration may affect pharmacokinetics and pharmacodynamics, it is the purpose of this article to review the general pharmacology of this entire range of clinically useful compounds.

It has been claimed that anaesthesia of mandibular pulpal and lingual soft tissue, as well as maxillary palatal soft tissue, results following buccal infiltration of the local anaesthetic Ultracaine (articaine HC1). However, this has never been scientifically proven and the aim of this investigation was to test these claims by comparing articaine to a standard anaesthetic, Citanest (prilocaine HC1). In order to study this, a double blind, randomized trial was conducted in healthy adult volunteers. In these subjects, the ability to induce maxillary and mandibular anaesthesia following buccal infiltration with articaine (as compared to prilocaine given contralaterally), was determined by measuring sensation to electrical stimulation at the tooth, buccal and lingual soft tissue at each of the four non-carious, non-restored, second molars. Results showed that there were no statistically significant differences between articaine and prilocaine in their ability to induce anaesthesia for any tissue at any of the six sites (p greater than 0.05) as determined by chi-square analysis. Analysis of effect on sensation for 25 minutes post-administration also failed to demonstrate a difference between the two drugs. Therefore, these data are not consistent with superior anaesthesia efficacy by articaine at any site, including the mandibular pulpal, lingual or maxillary palatal tissues, in the second molars studied.

Numerous potential problems have been associated with long term or occupational exposure to both nitrous oxide and halothane. Despite the lack of firmly established cause-and-effect relationships, particularly in humans, it would seem prudent to use techniques that minimize operator exposure. With this in mind, a scavenging system for use in both conscious sedation and general anesthetic techniques was developed which fulfills the requirements of both general dentists as well as those administering general anesthesia. This paper describes this system and its adaptation to the commonly used Magill circuit. It also briefly reviews the factors involved in potential toxicity caused by long term exposure to nitrous oxide and halothane.