Numerous injection techniques are available to provide clinically adequate anesthesia of the teeth and soft and hard tissues in the maxilla. Selection of the specific technique to be used is determined, in large part, by the nature of the treatment to be provided. The following techniques are available:
1: Supraperiosteal (infiltration), recommended for limited treatment protocols.
2: Periodontal ligament (PDL, intraligamentary) injection, recommended as an adjunct to other techniques or for limited treatment protocols.
3: Intraseptal injection, recommended primarily for periodontal surgical techniques.
4: Intracrestal injection, recommended for single teeth (primarily mandibular molars) when other techniques have failed.
5: Intraosseous (IO) injection, recommended for single teeth (primarily mandibular molars) when other techniques have failed
6: Posterior superior alveolar (PSA) nerve block, recommended for management of several molar teeth in one quadrant.
7: Middle superior alveolar (MSA) nerve block, recommended for management of premolars in one quadrant.
8: Anterior superior alveolar (ASA) nerve block, recommended for management of anterior teeth in one quadrant.
9: Maxillary (V2, second division) nerve block, recommended for extensive buccal, palatal, and pulpal management in one quadrant.
10: Greater (anterior) palatine nerve block, recommended for palatal soft and osseous tissue treatment distal to the canine in one quadrant.
11: Nasopalatine nerve block, recommended for palatal soft and osseous tissue management from canine to canine bilaterally.
12: Anterior middle superior alveolar (AMSA) nerve block, recommended for extensive management of anterior teeth, palatal and buccal soft and hard tissues.
13: Palatal approach-anterior superior alveolar (P-ASA) nerve block, recommended for treatment of maxillary anterior teeth and their palatal and facial soft and hard tissues.
The area of treatment is flooded with local
anesthetic. An incision is made into the same area (arrow).
Local anesthetic is deposited near the larger terminal nerve endings (arrow). An incision is made away from the site of injection.
Local anesthetic is deposited close to the main nerve trunk, located at a distance from the site of incision (arrow).
Posterior Superior Alveolar Nerve Block: (Tuberosity block, zygomatic block.)
It is used to achieve pulpal anesthesia, the PSA nerve block is effective for the maxillary third, second, and first molars (in 77% to 100% of patients). However, the mesiobuccal root of the maxillary first molar is not consistently innervated by the PSA nerve. In a dissection study by Loetscher and associates, the middle superior alveolar nerve provided sensory innervation to the mesiobuccal root of the maxillary first molar in 28% of specimens examined. Therefore a second injection, usually supraperiosteal, is indicated after the PSA nerve block when effective anesthesia of the first molar does not develop. Loetscher and associates concluded by stating that the PSA nerve usually provides sole pulpal innervation to the maxillary first molar, and that a single PSA nerve block usually provides clinically adequate pulpal anesthesia.