Intradental nerve fibers (IDN)

Intradental nerve fibers are the sensory axons located within the dental pulp and the inner portions of dentinal tubules that mediate the sensation of dental pain. These fibers are categorized into myelinated A-delta fibers, which respond to hydrodynamic stimuli with sharp pain, and unmyelinated C-fibers, which respond to inflammatory mediators with dull, aching pain (StatPearls, 2023). According to the hydrodynamic theory, external stimuli cause fluid movement within the dentinal tubules, which mechanically stimulates these nerve endings (Brännström, 1963). In conditions like dentin hypersensitivity, the exposure of these tubules leads to increased nerve activation and pain. Pharmacological agents target these fibers by either blocking ion channels to prevent action potential propagation or by altering the ionic environment to induce nerve desensitization (Journal of Clinical Periodontology, 2008). Common treatments include potassium salts, which diffuse through the tubules to depolarize the nerve membrane and inhibit signal transmission (Markowitz & Kim, 1990). Local anesthetics like lidocaine are also used to block voltage-gated sodium channels on these fibers during dental procedures. Understanding the physiology of these fibers is crucial for developing effective desensitizing toothpastes and analgesic treatments. Therapeutic challenges include ensuring the delivery of agents through the mineralized dentin to reach the nerve endings effectively. Safety concerns primarily involve the potential for masking underlying dental pathologies such as caries or pulpitis.

Other names

Dental nerve fibers in dentinal tubulesPulpal nerve fibersDentinal nerve endingsA-delta fibersC-fibers

Nerve desensitization via potassium-induced depolarization; blockade of voltage-gated sodium channels.