D G Harper’s research while affiliated with University of Toronto and other places

The administration of intravenous agents is the most commonly used method in Canada and the United States to produce sedation or general anesthesia for dental procedures. Ketamine, a dissociative anesthetic, has several advantageous physical, pharmacokinetic, and pharmacodynamic properties. It can be used to induce anesthesia, sedation, analgesia, and amnesia. Ketamine can maintain functional residual capacity, induce bronchodilation, and avoid cardiovascular depression. However, adverse effects have been demonstrated, such as cardiovascular stimulation and unpleasant emergence phenomena, both of which may be modulated by supplementation with benzodiazepines. An increase in the use of ketamine for ambulatory anesthesia has recently been advocated. This review of the literature supports the use of ketamine as an effective agent for selected anesthetic procedures.

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.

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.

Claims that labial infiltration of the local anesthetic articaine HCl (Ultracaine DS) results in anesthesia of mandibular pulpal as well as maxillary and mandibular lingual soft tissue have never been scientifically substantiated. The aim of this investigation was to evaluate these claims, by comparing articaine to a standard anesthetic, prilocaine HCl (Citanest Forte). To investigate this, a double blind, randomized study was conducted in healthy adult volunteers. In each volunteer, the ability to induce maxillary and mandibular anesthesia following labial infiltration with articaine was compared to prilocaine given contralaterally. Anesthesia was determined by measuring sensation to electrical stimulation at the tooth, labial and lingual soft tissue for each of the 4 non-carious, non-restored, canines. Results showed that mandibular canine pulpal anesthesia had a success rate of 65% for articaine and 50% for prilocaine. Success rates for palatal and lingual anesthesia averaged 5% for each agent. As determined by chi-square analysis, no statistically significant differences were found between articaine and prilocaine for any tissue at any of the 6 sites (P greater than 0.05). A time-course assessment also failed to demonstrate a difference between the two drugs. Therefore these data are not consistent with superior anesthesia efficacy being produced by articaine at any site, including the mandibular pulpal, lingual or maxillary palatal tissues, in the canine teeth studied.