Dendritic cells (DC) represent an important link between innate and adaptive immunity, which play an important role during the immune response against pathogens. There are several populations and subpopulations of DC, but mainly two subpopulations are characterized: the classic DC specialized in the processing and presentation of the antigen; and the plasmacytoid DC that have a high phagocytic activity and capacity for the production of cytokines. This chapter aims to present the current aspects related to the most relevant characteristics and functions of DC, as well as their role in host defense against infections by viruses, parasites, bacteria, and fungi.

Aim To evaluate whether treatment with resiniferatoxin (RTX) is capable of lowering the plasma levels of PGE2 and TNF‐α, as well as histopathological parameters in inflammation of pulp tissue in a mouse experimental model. Methodology Ten groups of six BALB/c mice were formed as follows: healthy group (HC), healthy group treated with RTX (HRTX), two groups with pulp inflammation at 14 and 18 hours (PI14/PI18), six groups with pulpal inflammation plus treatment with Ibuprofen (IBU14/IBU18), dexamethasone (DEX14/DEX18) and resiniferatoxin (RTX14/RTX18) at 14 and 18 hours, respectively. Pulpal inflammation was induced through occlusal exposure of the pulp of the maxillary first molar. The plasma levels of PGE2 and TNF‐α and the histological parameters of the pulp tissue of the HC and HRTX groups were evaluated at the time of acquiring the animals. In the other groups, the plasma levels of PGE2 and TNF‐α and the histopathological parameters were evaluated at 14 and 18 hours after pulp damage. Plasma levels of PGE2 and TNF‐α were quantified by ELISA, and the histopathological parameters were evaluated by H/E staining. Statistical significance was determined by one‐way analysis of variance (ANOVA) to test for overall differences between group means. Results A significant increase (*p < .05) in plasma levels of PGE2 and TNF‐α occurred 14 and 18 hours after pulp damage. In addition, treatment with RTX significantly decreased (*p < .05) the plasma levels of PGE2 and TNF‐α at 14 and 18 hours after pulp damage, as well as the infiltrate of inflammatory cells at 18 hours after pulp damage, similarly to treatment with ibuprofen and dexamethasone. Conclusion It was possible to detect systemic levels of PGE2 and TNF‐α at 14 and 18 hours after pulp damage. Likewise, treatment with RTX was associated with an anti‐inflammatory effect similar to treatment with ibuprofen and dexamethasone. These findings place resiniferatoxin as a therapeutic alternative in the treatment of inflammatory diseases in Dentistry.