DENTAL ANESTHESIA (LOCAL ANESTHESIA)

Dental anesthesia (or dental anaesthesia) is a field of anesthesia that includes not only local anesthetic but sedation and general anesthesia.

Local anesthetic agents in dentistry

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 anesthetic agents in current use include articaine (also called septocaine or ubistesin), 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 or other vasoconstrictor that allow the agent to last longer and also controls bleeding in the tissue during procedures. Usually the case is classified using the ASA Physical Status Classification System before any anesthesia is given.

Types of local anesthesia in dentistry

• Nerve Block— a common form of local dental anesthesia; blocks the reception of pain in one region of the mouth at a time.
• Infiltration given inferior to the root the tooth involved in the dental work; used usually for minor procedures such as restorations.
• Palatal block given into the hard palate using pressure anesthesia; useful in anesthetizing the palate side of the maxillary teeth.
• Intraosseous an injection of local anesthetic given directly into the osseous (bone) structure of the tooth for more involved dental procedures such as surgery or endodontic therapy (root canals).
• Intrapulpal an injection of local anesthetic given directly into the pulp of the tooth to completely desensitize the tooth.
• Pressure anesthesia---- pressure with a cotton swab in the area to distract the nerve sensation of pain when the needle enters certain areas such as palatal tissue.
• Electrical Nerve Block--- a technology that involves using electrical current to block the reception or generation of pain signals; the pain control can be transient.
• Acupuncture ---An alternative to chemical or electrical blocks, but is rarely used.

Most common local anesthetic procedure

The Inferior alveolar nerve anaesthesia or block or IANB (sometimes termed "inferior dental block", or wrongly referred to as the "mandibular block") probably is anesthetized more often than any other nerve in the body. 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 mandibular teeth, lower lip, chin, and parts of the tongue, which is effective for dental work in the mandibular arch. To anesthetize this nerve, the needle is inserted somewhat posterior to the most distal mandibular molar on one side of the mouth. The lingual nerve is also anesthetized through diffusion of the agent to produce a numb tongue as well as anesthetizing the floor of the mouth tissue, including that around the tongue side or lingual of the teeth.

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, such as affecting hearing (auriculotemporal nerve).

The facial nerve lies some distance from the inferior alveolar nerve within the parotid salivary gland, but in rare cases anesthetic can be injected far enough posteriorly to anesthetize that nerve. The result is a transient facial paralysis, with the injected side of the face having temporary loss of the use of the muscles of facial expression that include the inability to close the eyelid and the drooping of the labial commissure on the affected side for a few hours, which disappears when the anesthesia wears off.

In contrast, the superior alveolar nerves are not usually anesthetized directly because they are difficult to approach with a needle. For this reason, the maxillary arch is usually anesthetized locally for dental work by inserting the needle beneath the oral mucosa surrounding the teeth so as to anesthetize the smaller branches.

Dental syringe

A dental syringe is a syringe used by licensed dental professionals for the injection of a local anesthetic. It consists of a breech-loading syringe fitted with a sealed cartridge containing anesthetic solution.

Other drugs used in combination with general anesthesia in dentistry

• Decadron a steroid is often administered through IV to suppress inflammation and swelling resulting during the surgery while under general anesthesia.

Ondansetron brand named Zofran is often administered to prevent nausea during the surgery which may result from the blood draining into the stomach while under general anesthesia, or it is given after the procedure for postoperative nausea which may result from the anesthesia itself which was administered.    

The use of inhalation sedation and local anaesthesia can be an alternative to general anaesthesia for dental extractions in children

SIDE EFFECTS

Source

wikipedia