Forms of dental anesthesia (or dental anaesthesia) is a spectrum of anesthesia that includes not only local anesthetics but sedation and general anesthesia.
The most commonly used local anesthetic is lidocaine (also called xylocaine or lignocaine), a modern replacement for novocaine and procaine. Its half-life in the body is about 1.5–2 hours. Other local anesthetics in current use include articaine, septocaine, marcaine (a long-acting anesthetic), and mepivacaine. A combination of these may be used depending on the situation. Also, most agents come in two forms: with and without epinephrine.
The most common technique, effective for the lower teeth and jaw, is inferior alveolar nerve anesthesia. An injection blocks sensation in the inferior alveolar nerve, which runs from the angle of the mandible down the medial aspect of the mandible, innervating the lower teeth, lower lip, chin, and tongue. The inferior alveolar nerve probably is anesthetized more often than any other nerve in the body. To anesthetize this nerve, the dentist inserts the needle somewhat posterior to the patient’s last molar. Several nondental nerves are usually anesthetized during an inferior alveolar block. The mental nerve, which supplies cutaneous innervation to the anterior lip and chin, is a distal branch of the inferior alveolar nerve. When the inferior alveolar nerve is blocked, the mental nerve is blocked also, resulting in a numb lip and chin. Nerves lying near the point where the inferior alveolar nerve enters the mandible often are also anesthetized during inferior alveolar anesthesia. For example, the lingual nerve can be anesthetized to produce a numb tongue. The facial nerve lies some distance from the inferior alveolar nerve, but in rare cases anesthetic can diffuse far enough posteriorly to anesthetize that nerve. The result is a temporary facial palsy (paralysis or paresis), with the injected side of the face drooping because of flaccid muscles, which disappears when the anesthesia wears off. If the facial nerve is cut by an improperly inserted needle, permanent facial palsy may occur.
A wide variation has been found in the training for and practice of sedation and general anesthesia within the dental profession in the United States. Safe, effective pain and anxiety control techniques are an essential part of dentistry. A survey designed to be a snapshot of common practices provides insight into this limited area of research.
An article in the June issue of the journal Anesthesia Progress reports the results of a survey of 717 providers. The questionnaire-based survey, conducted from April 2008 to December 2008, investigated training, practice characteristics, and anesthesia techniques of dental care providers.
A universal instructional standard for sedation and general anesthesia is lacking in the training requirements of US dental boards, although similarities do exist. Most commonly, training was through oral surgery residencies. Overall, respondents reported that 33% of their postgraduate instruction was hospital-based.
Thirty-five percent of dental anesthesia assistants were without formal training, closely followed by 33.5% who received training through an American Association of Oral Maxillofacial Surgeons program. A much lower 7.3% were trained through an American Dental Society of Anesthesiology program.
Other aspects of the survey included types of patients and procedures for which sedation or general anesthesia were used. The questionnaire also asked which medication agents were most commonly used and how they were administered. Postanesthesia care was most commonly found to be given by the actual provider (51.7% of cases), but a nurse or assistant often provided recovery care as well (45%).