Repair Responses of Dental Pulp to Tooth Injury and Biological Properties of Dentin-pulp Complex
- Publisher: 新潟歯学会
Histocompatibility Antigens Class II | 窩洞形成 | Regeneration | Tooth Replantation | 歯の再植 | Dental Pulp | 免疫組織化学 | Dental Cavity Preparation | 象牙芽細胞 | 歯髄 | クラスＩＩ組織適合抗原 | 再生 | Odontoblasts | Immunohistochemistry
mesheuropmc: stomatognathic diseases | stomatognathic system
Regeneration-the creation of a new tissue after the original one has been lost-is the fundamental biological capability in an organism. Numerous organs are considered to contain stem cells referred to as adult stem cells, even in the adult. Adult stem cells can give rise to a limited set of adult tissue types. In the field of clinical dentistry, it is well-known that the dentin-pulp complex is capable of repair after tooth injuries such as tooth replantation/transplantation or restorative procedures including cavity preparation. This phenomenon may indicate that dental pulp stem cells exist in the pulp tissue of the matured tooth. However, the exact origin of the cells responsible for secretion of reparative dentin matrix has not been clearly identified. The existence of the dental pulp stem cells in the human wisdom or deciduous teeth, which has been reported by the recent studies, would be informative for the regenerative treatment of teeth. This review focuses on the repair responses of dental pulp to tooth injury and the possible role of antigen-presenting cells and heat shock proteins (HSPs) in the reparative processes. Moreover, attention is focused on adult stem cells in the pulp tissue. HSPs are expressed in normal various cells as well as under stressful conditions, although they were first discovered under the latter conditions. These proteins have been reported to possess diferent functions including molecular chaperones or a general mediator of inflammation. Our recent studies have demonstrated that the intense HSP-25-immunoreactivity is found in the differentiated odontoblasts. Tooth injuries such as cavity preparation or tooth replantation cause the degeneration of the odontoblast layer to result in the loss of HSP-25-immunoreactions in the suffered dental pulp. Numerous class Ⅱ major histocompatibility complex (MHC)-positive cells appeared temporarily along the pulp-dentin border after these injuries. Subsequently, newly differentiated odontoblasts acquire an HSP-25-immunoreactivity. These findings indicate that the time course of changes in the expression of HSP-25-immunoreactivity reflects the degeneration/regeneration process of odontoblasts and that the temporal appearance of the class ⅡMHC-positive cells at the pulp-dentin border is suggestive of their participation in odontoblast differentiation as well as in initial defense reactions during the pulpal regeneration process. Thus, it is important to recognize that a variety of cellular signaling from these components may be present in the extracellular milieu at sites of injury in the pulp tissue.