IMMUNOLOGY

Detailed explanation-1: -Dentinal pain, caused by A-delta fibers, is more transitory and is used more often than C-fibers for diagnostic vitality tests. C-fibers are usually associated with patho-physiology. A-delta and C-fibers transmit pain signals through different pain pathways in the CNS to different regions of the thalamus.

Detailed explanation-2: -The extracellular levels of bradykinin are significantly elevated during irreversible pulpitis, contributing to the early stages of inflammation and pain [20]. Irritation of the dental pulp produced by bacteria, mechanical stimuli, or chemical stimuli can cause inflammation.

Detailed explanation-3: -The unmyelinated C fibers respond to thermal, mechanical, and chemical stimuli and produce the sensation of dull, diffuse, aching, burning, and delayed pain. The myelinated A-delta fibers respond to mechanical (pressure) stimulus and produce the sensation of sharp, localized, fast pain.