Upregulation of transient receptor potential ankyrin 1 (TRPA1) but not transient receptor potential vanilloid 1 (TRPV1) during primary tooth carious progression

To quantify the changes in Transient Receptor Potential Ankyrin 1 (TRPA1) and Transient Receptor Potential Vanilloid 1 (TRPV1) expression throughout the process of inflammation induced by caries.Forty primary teeth were obtained from children requiring dental extractions under local or general anesthesia. The teeth were grouped according to three stages reflecting the progression of dental caries: nine with intact dentin, 15 with exposed dentin (but not to the extent of the pulp), and 16 with exposed pulp. Immunofluorescence was used to validate the presence of dental pulp inflammation by demonstrating a decrease in NF-κB nuclear translocation. The expression levels of TRPA1 and TRPV1 were quantified in the pulp horn and the subodontoblastic and midcoronal regions of the pulp.The percentage of cells with NF-κB nuclear translocation was highest for teeth with intact dentin and decreased progressively during the progression of caries. TRPA1 expression was lowest in intact teeth and gradually increased as caries advanced. TRPV1 expression was similar in teeth with intact dentin, exposed dentin, and exposed pulp.The differences in TRPA1 and TRPV1 expression in response to caries suggest that these receptors play unique roles in the immune response during the progression of caries and that the pathophysiology of inflammation in the dental pulp varies between the early and late stages of caries.