REGIONAL ANESTHESIA OF THE INFRAORBITAL AND INFERIOR ALVEOLAR NERVES DURING NONINVASIVE TOOTH-PULP STIMULATION IN HALOTHANE-ANESTHETIZED DOGS

Objective-To document that regional anesthesia of the infraorbital and inferior alveolar nerves would abolish reflex-evoked muscle action po tentials (REMP) in the digastricus muscle during noninvasive stimulati on of tooth pulp in halothane-anesthetized dogs. Design-Prospective st udy. Animals-9 healthy female dogs between 2 and 6 years old. Procedur e-Dogs were anesthetized using halothane. An alligator clip anodal ele ctrode was attached to the tooth to be stimulated, and a platinum need le cathodal electrode was inserted in adjacent gingival mucosa. The ca thodal and anodal electrodes were moved to the left upper and lower ca nine, fourth premolar, and first molar teeth for sequential stimulatio n. Baseline recording of REMP was made for each tooth. Catheters were inserted percutaneously in the infraorbital and mandibular canals. Sal ine (0.9% NaCl) solution was injected al each catheterized site in 3 c ontrol dogs, and chloroprocaine hydrochloride was injected at each cat heterized site in 6 test dogs. Each tooth was stimulated every 10 minu tes for 90 minutes (test dogs) or every 10 minutes for 30 minutes and al 90 minutes (control dogs), and REMP was recorded. Results-REMP was abolished within 10 minutes in all test dogs, except during stimulatio n of the lower first molar in 1 dog. In 4 dogs, duration of blockade w as less than 90 minutes. The REMP was not restored within 90 minutes f or the upper teeth in 1 dog and within 2 hours for ail teeth in anothe r dog. At 24 hours, REMP was restored for all teeth except the lower l eft canine in 1 dog. The REMP was restored for the lower left canine i n that dog at 96 hours. The REMP was not abolished at any time in cont rol dogs. Clinical Implications-Regional anesthesia of the infraorbita l and inferior alveolar nerves may effectively provide analgesia for d ental procedures In dogs.