Beyond hydrodynamics: The role of ion channels in dentine hypersensitivity

Objectives: This review examined the roles of ion channels in dentine hypersensitivity (DH), highlighting their contributions to pain perception and intercellular communication between odontoblasts and afferent sensory neurons. Background: Dentine hypersensitivity is a prevalent condition resulting from the exposure of dentinal tubules to the oral environment, leading to sharp pain triggered by mechanical, thermal, chemical, and osmotic stimuli. The prevailing hypothesis integrates aspects of the hydrodynamic and odontoblast transducer theories. It suggests that rapid intratubular fluid movement activates specific ion channels in odontoblasts and trigeminal sensory neurons, converting external stimuli into electrical signals interpreted as pain by the central nervous system. Data & Sources: A comprehensive literature review was conducted on ion channels involved in DH, with a focus on transient receptor potential (TRP) channels, Piezo channels, acid-sensing ion channels (ASICs), as well as other voltage-gated ion channels. Particular emphasis was placed on their physiological roles, responsiveness to stimuli, and contributions to DH pain. Results: PIEZO, TRP, and ASICs respond to pressure, heat, acidic environments, and chemical irritants, all of which contribute to DH pain. Activation of odontoblastic ion channels results in the release of adenosine triphosphate and glutamate, which bind respectively to purinergic and glutamate receptors on sensory neurons. This interaction induces depolarization, generating action potentials that transmit pain signals to the brain. Conclusion: The diverse ion channels involved in dentine hypersensitivity play a crucial role in intercellular communication that leads to pain perception. However, their widespread physiological functions make direct pharmacological targeting challenging due to potential systemic effects. Clinical significance: The use of antagonists for targeting specific ion channels involved in dentine hypersensitivity is difficult because of their involvement in other important physiological processes. Hence, clinical management strategies focusing on dentinal tubule occlusion or dentine desensitisation remain the safest and most effective approaches.