Dentin hypersensitivity pain condition that develops as a result of irradiation of the surface of the dentin. The condition is most often located in the cervical area of the tooth (6, 42, 50) and can be a significant clinical problem. As a rule, patients complain of a sharp or stabbing pain, which is caused by cold food or drinks, brushing your teeth or even a slight touch of exposed surface dentin (42, 50, 61). Pain symptoms can be very intense, continue throughout the year and, thus, have a large impact on the daily life of the patient. State and main features of sensitive dentin and hydrodynamic nerve activation mechanism as the basis for the sensitivity of the dentin, described in detail in the previous section on the sensitivity of the dentin. the following text will focus on the factors that can prolong the state, especially the role of inflammatory neural mechanisms and effects.
In favourable cases, repair reactions pulp and dentin complex in response to the dentin exposure, as a rule, lead to a gradual tubule unit on intratubular salinity and/or irritation of the dentin formation for the protection of pulp, leading to natural desensitization dentin.
However, sometimes the dentinal tubules can remain open and dentine sensitivity is maintained (6, 42, 50). Such a change in local responses dentin is poorly understood. This may be due to a compromised defense capacity of the pulp tissue or intensive and continuous external irritation. Possible differences in the repair reactions in coronal against cervical pulp and dentin, the complex may explain why persistent symptoms of increased sensitivity dentin often found in the cervical and the root zone, but rarely in coronal dentin (42, 50). In this regard, the structure intradental innervation interesting, showing a dense network of nerve endings in the crown (7); afferent nerves can play an important role in the repair and protective reactions pulp and dentinal mineralization (11, 12, 25). In addition, the time course of dentin impact may be significant. Gum recession in the cervix can cause much quicker exposure than that caused by the attrition of occlusive or the tooth enamel and, thus, do not allow sufficient time for a favorable repair reactions to take place in the pulp. If the dentinal tubules remain open, it may cause an inflammatory reaction in the pulp and paper (6) and more or less constant pain condition.
The method of choice in the treatment of dentinal pain will block patent tubules. The mechanism of action of a number of products marketed for hypersensitive dentin, based on this principle, and in some cases, dentine sensitivity can remain even when the tubes were blocked completely (42). This can be a sign of inflammation of the pulp of the tooth and the subsequent sensitization intradental nociceptors. Thus, the products used in the clinic for the treatment of hypersensitivity dentin may, in some cases, have diagnostic value of discrimination inflamed teeth.
Exposed dentin with patent tubules sensitive, if the underlying pulp is vital. The definition of "hypersensitive dentin" will mean that dentin may be more sensitive than usual, and it is tempting to say so, considering how extremely intense dentinal pain sometimes the answers can be (42). In fact, electrophysiological and morphological studies presented above give support to this concept. Namely, for local application of serotonin in healthy teeth can increase the sensitivity of the intradental-fiber, dentinal stimulation (42, 43). In addition, morphological and functional changes showing germination pulp nerve endings (8-12), expansion of the receptive field of the tooth pulp fiber (10, 44), and the activation of the "silent" nociceptors (44) may contribute to improving the sensitivity of dentin in inflamed teeth. Accordingly, in the teeth with dentin hypersensitivity, the tooth pulp inflammatory reactions may play a significant role in developing and maintaining the painful symptoms. It should be noted, however, that the higher neural changes are reversible. They can be solved if the irritation of the pulp of the tooth may be cancelled, and, consequently, an inflammatory reaction fades (8, 9). Thus, effective tubule unit may reduce the sensitivity of the dentin both directly, by reducing the hydraulic conductivity, and indirectly, by resolution resolution of the tooth pulp neural changes caused by inflammation...