The Maxillary Neurovascular Canals as the Basis for the Local Anesthesia Efficacy

Abstract

It is not known the way in which a local anesthetic, following the Anterior Middle Superior Alveolar (AMSA) anesthesia, reaches the superior dental plexus. Consequently, the aim of the study was to examine the possible route of diffusion of a local anesthetic from the anterior lateral palatal injection to the superior dental plexus. The palatal and alveolar regions of 48 dry maxillae were examined and 6 autopsy specimens of the same region were prepared for histological and immunohistochemical analysis. The study revealed palatal and alveolar process openings in all the specimens. They average 6.3 in number close to the central incisor, 5.2 to the lateral incisor, 3.7 to the canine, 3.8 to the 1st premolar, and 3.9 to the 2nd premolar. The microscopic structure of the epithelium, lamina propria, submucous layer, arteries and nerves, periosteum, and cortical and spongious bone was described in detail. The neurovascular pores and canals had a diameter of their opening of 90.28–1,230.62 μm (mean, 893.62 μm). The initial part of the canals varied in diameter between 523.42 μm and 903.04 μm (mean, 622.93 μm). The canals penetrated the cortical bone and usually terminated in the spongious bone towards the alveolar process. They contained a larger artery or several smaller arteries, some veins, a few tiny nerves, collagen fibers type I, and small collections of the fatty cells. The neurovascular canals and the pores most likely represent a route for diffusion of an anesthetic from the lateral palatal region to the superior dental plexus.