Effects of inflammation on dental sensory nerves and vice versa.

A brief review of the normal sensory innervation of teeth is presented, especially concerning the fibers that are immunoreactive (IR) for calcitonin gene-related peptide (CGRP). Numerous CGRP-IR fibers innervate coronal dentin at sites populated by primary odontoblasts and associated pulp cells that synthesize nerve growth factor (NGF). If the primary odontoblasts and adjacent pulp cells are lost as a consequence of injury, CGRP-IR dentinal innervation is greatly reduced. The responses of CGRP-IR nerve fibers to pulpal injury are reviewed. Those reactions show that pulpal sensory nerve fibers can alter the size, shape and immunoreactivity of their terminal branches in response to different stages of inflammation and healing.