The Evolution of Neuroscience as a Research Field Relevant to Dentistry

Abstract

The field of neuroscience did not exist as such when the Journal of Dental Research was founded 100 y ago. It has emerged as an important scientific field relevant to dentistry in view of the many neurally based functions manifested in the orofacial area (e.g., pain, taste, chewing, swallowing, salivation). This article reviews many of the novel insights that have been gained through neuroscience research into the neural basis of these functions and their clinical relevance to the diagnosis and management of pain and sensorimotor disorders. These include the neural pathways and brain circuitry underlying each of these functions and the role of nonneural as well as neural processes and their “plasticity” in modulating these functions and allowing for adaptation to tissue injury and pain and for learning or rehabilitation of orofacial functions.

Orofacial Neuropathic Pain-Basic Research and Their Clinical Relevancies

“…After trigeminal nerve injuries, such as the inferior alveolar nerve, mental nerve, and infraorbital nerve transection, the primary afferent neurons become hyperexcitable, resulting in satellite glial cell activation within TG. After hyperactivation of Vc and C1-C2 nociceptive neurons, microglial cells and astrocytes are further activated ( Iwata and Sessle, 2019 ). As mentioned earlier, minocycline is known to inhibit the activation of microglia, and bioactive substances and other cytokines, such as nitric oxide, prostaglandin, IL-1, IL-1β, IL-6, are involved in the modulation of microglial activities in the central nervous system ( Iwata and Sessle, 2019 ).…”

Cognitive changes and neural correlates after oral rehabilitation procedures in older adults: a protocol for an interventional study

“…Contemporary orofacial neuroscience [60] related research has emphasized the importance of sensorimotor regulation [61][62][63][64][65][66][67][68][69][70] and adaptation to the altered oral environment during biting [64,[71][72][73][74] and chewing behaviors [71]. Further, recent studies have discussed the significance of retaining natural dentition and optimizing oral functions in people with a dental prosthesis [62,63,[75][76][77][78].…”

Glia and Orofacial Pain: Progress and Future Directions

“…Dental pulp Schwann cells also function as a reservoir of multipotent mesenchymal stem cells that can differentiate into odontoblasts, which are specialized pulp cells critical to hard tissue repair in teeth [110]. In addition to the dynamic role within the pulp, glial cell expression and activity within the TG and the TNC are responsive to dental pulp inflammation and injury and may play a role in persistent pain after pulp injury [8][9][10]111,112]. Interestingly, glial cell activation following pulp inflammation could lead to increased excitabilities of adjacent uninjured TG neurons, which could explain the clinical phenomena of ectopic tooth pain, in which pain originating from a single inflamed dental pulp, can be difficult to localize and produce pain in other non-injured orofacial structures [8,9,46,112,113].…”

“…Chronic pain is associated with functional, structural plasticity and reorganization of the pain circuits [166]. Glial plasticity has been shown in the thalamus, the descending modulatory pathway as well as the limbic systems in a few orofacial pain conditions [8,31,[170][171][172][173][174]. How glial cells modulate neuronal plasticity both functionally and structurally and their role in the organization of pain circuits at different disease states remains a daunting task in the orofacial pain field.…”

“…Cellular and molecular insights of orofacial pain are largely derived from animal models, yet behavioral phenotyping in the orofacial region is more challenging than other body regions (e.g., hind limb). The neuronal involvement of orofacial pain includes peripheral sensitization of the primary afferent neurons, central sensitization in the spinal cord and brain neurons, as well as the loss of inhibitory synaptic transmission and enhanced descending facilitation in the pain pathway, transitioning acute pain to chronic pain [6][7][8][9]. The non-neuronal mechanisms in pain, such as the contribution of glial cells, are not as well studied in the orofacial region compared to the other body regions [6].…”