The Anesthetic Effect of Anterior Middle Superior Alveolar Technique (AMSA) for Non-surgical Periodontal Procedures: a Randomized Controlled Clinical Study

Patients with periodontal disease often have deep pockets that require scaling and root planing (SRP) and, hence, anesthesia of the periodontal tissues to control pain may be necessary. The proper anesthesia of the mucogingival tissues in the maxilla may need up to five injections of anesthetic solution. Thus, these various injections will anesthetize the (i) posterior superior alveolar, (ii) middle superior alveolar, (iii) anterior superior alveolar, (iv) greater palatine and (v) nasopalatine nerves. Although these series of anesthetic injections are effective to anesthetize the tissues of the jaw, they can reach other unwanted structures, such as the upper lip, the nostrils and lower eyelid, causing postoperative discomfort to the patient and minimizing the patient's ability to smile and show the top line of the lip.

In order to minimize the side effects and allow a smaller number of punctures and amount of anesthetic solution used for control the pain in the maxilla, Friedman & Hochman (1998) described the anterior middle superior alveolar anesthetic technique (AMSA), for various dental procedures in the jaw. The AMSA has the ability to not anesthetize, undesirably, other anatomical structures beyond the periodontium and teeth such as upper lip, bridge of the nose and lower eyelid. This advantage occurs due to the fact that the anesthetic solution is administrated in a small location on the palate where it is not able to reach the sensory fibers of the lips and face and, therefore, does not alter the activity of the muscles that deal with facial expressions. In addition, the administration of only 0.6 to 0.9 ml of anesthetic, is able to induce anesthesia of the pulpal and soft tissues of the palate region. This is a significantly smaller amount of anesthetic than what is usually administered for the desired analgesia for dental and periodontal structures.

The biological plausibility of the AMSA technique is due to the resilience of the tissues of the palate and the application of the anesthetic solution with controlled pressure and flow, so that it reaches the underlying bone and neurovascular anatomy. The penetration of the anesthetic in the tissues from the palate promotes the diffusion of the solution through numerous channels of nutrients and pores in the cortical bone of the palate4. With the spread of the anesthetic in the tissues, structures typically innervated by the anterior superior alveolar nerves, middle and posterior, nasopalatine and greater palatine are anesthetized.

Several reports have suggested that this technique is effective to anesthetize teeth and maxillary tissues extending from the mesial root of first molar to central incisor with a single infiltration. However, there are no controlled studies in the literature that specifically evaluate the vestibular tissue analgesia, considering patient comfort during the procedure for scaling and root planing.

Therefore, the aim of this study was to evaluate the anesthetic efficacy of AMSA technique of tissues at the buccal aspect of the ridge compared to conventional supraperiosteal techniques in the buccal area during the process of scaling and root planing of periodontal pockets in the jaw.