Dental Pain Mechanisms

Fifty years of development of neuroscientific insights into oro‐facial pain and its control

“…However, starting in the 1970s, this long-held concept that pain is the only sensation evoked from tooth pulp (and dentine) has been challenged as a result of findings that sensations other than pain could sometimes be elicited by intradental stimuli and that the pulp is actually innervated not only by small-diameter afferents but also by large-diameter afferents which elsewhere in the body are normally involved in sensations other than pain (for review, see Refs. [76,[95][96][97][98]). Thus, while pain is certainly the dominant sensory experience evoked by intradental stimuli, it has become apparent that caution is necessary before interpreting all sensory responses to tooth pulp stimulation as being solely associated with pain.…”

“…This is an intriguing topic worthy of intensive investigation, but several possible changes in periodontal tissues have recently been suggested to explain the limited pain sensitivity, including an upregulation of anti-nociceptive processes and a downregulation of pro-nociceptive processes within the periodontal tissues (see Refs. [98,106]). CNS modulatory processes could TA B L E 1 Ion channels expressed in dental sensory elements and associated cells.…”

“…This is an intriguing topic worthy of intensive investigation, but several possible changes in periodontal tissues have recently been suggested to explain the limited pain sensitivity, including an upregulation of anti‐nociceptive processes and a downregulation of pro‐nociceptive processes within the periodontal tissues (see Refs. [98, 106]). CNS modulatory processes could also conceivably contribute to limiting pain expression in periodontal disease, but it would be puzzling why these CNS‐based processes could be so effective in suppressing pain in periodontal disease as opposed to other chronic inflammatory pain conditions (see below).…”

“…glutamate, substance P, CGRP, ATP) released from the presynaptic axon terminals of nociceptive afferents and their excitatory actions on neurons in these pathways, and the modulatory influences on these neurons of projections from other CNS areas (for review, see Refs. [20, 76, 88, 90, 96, 98, 110]) (Figure 3B). The tracing and labelling techniques available in the 1970s, 1980s and 1990s were used for example to map the brainstem pathways of trigeminal nociceptive and non‐nociceptive afferents and the morphological features of the brainstem neurons receiving these inputs (e.g.…”

“…characteristics of neurons in these pathways, the several chemical mediators (e.g. glutamate, substance P, CGRP, ATP) released from the presynaptic axon terminals of nociceptive afferents and their excitatory actions on neurons in these pathways, and the modulatory influences on these neurons of projections from other CNS areas (for review, see Refs [20,76,88,90,96,98,110]…”