A comparison of the anterior middle superior alveolar nerve block and infraorbital nerve block for anesthesia of maxillary anterior teeth.

Background: The authors conducted a study to compare the efficacy of the anterior middle superior alveolar (AMSA) nerve block with that of the infra-orbital nerve block (IONB) in achieving pulpal anesthesia in the anterior maxilla.

Methods: Twenty-eight healthy adult volunteers received 1.0 milliliter of 2 percent lidocaine with 1:80,000 epinephrine as an AMSA nerve block or IONB via computer-controlled local anesthetic delivery (CCLAD) across two visits. The authors used electronic pulp testing to measure pulpal anesthesia. Participants provided subjective reports of lip numbness and injection discomfort. The authors analyzed the data by using the McNemar, Mann-Whitney and t tests.

Results: Anesthetic success, defined as two or more consecutive episodes of no sensation in response to maximal stimulation, was significantly greater with the AMSA nerve block than with the IONB in central (P = .012) and lateral (P < .001) incisors; however, anesthesia was achieved in only 42.9 percent of central incisors with the AMSA nerve block. The authors observed a significantly greater number of episodes of no response in the premolar and canine teeth after IONB. Onset of anesthesia was shorter after IONB in canines (P = .002) and central incisors (P = .022). The incidence of subjective lip numbness was 100 percent after IONB and 14.3 percent after AMSA nerve block (P < .001), with numbness lasting twice as long after IONB (P = .019). The authors noted no significant difference in injection discomfort between the two techniques (P = .768).

Conclusions: The IONB produced anesthetic success in canine and premolar teeth, with a more rapid onset than that for the AMSA nerve block. Although the AMSA technique was significantly more successful than IONB in attaining incisor anesthesia, it was ineffective for central incisors, as assessed according to rigorous electronic pulp testing. The IONB and AMSA nerve block produced similar levels of injection discomfort.