This paper shows the innervation of teeth, beginning with the examination of embryonic development of the teeth and the trigeminal and sympathetic fibers that make their innervation. In the next section, the histology of nerve fibers is described through a general description of neurons, synapses and nerve fibers to the elements of the tooth innervation (pulpal and periodontal), with particular reference to odontoblasts whose function in the transmission of pain stimuli is discussed. The anatomy of the trigeminal nerve and upper neck ganglia participating in tooth inervation is described, along with the possible anatomical variation in tooth innervation that every dentist should have in mind when administering anesthesia. Further on, dental pain is described, first through the theories of the emergence of dentinal pain (of which the hydrodynamic is considered to be the most accurate), then through the reaction of the pulp-dentine complex to different stimuli in which we see how nerve fibers trigger neurogenic inflammation by releasing inflammatory mediators such as substance P, ending with the description of the pain path, the pulp-reflex arch and the modulation of dental pain. The phenomenon of referred pain is explained by the convergence of pain impulses in the subnucleus caudalis and other mechanisms. Lastly, conditions that can cause pain of orofacial regions are shown, which are not to be overlooked when making a diagnosis, so as not to provide wrong or unnecessary treatment.