Abstract
CD90 expression and immunoreactive cell localisation in rat dental pulp cells after cavity preparation was investigated. Cavity preparation was performed on the maxillary first molar of 8-week-old Wistar rats (n = 36), and immunohistochemistry and quantitative real-time PCR were performed. CD90-immunoreactivity was observed among subodontoblastic cells in the control group. One day after cavity preparation, the CD90-immunoreactivity disappeared under the cavity area. While CD90-immunoreactivity was faint after 3 days, the re-arrangement of odontoblasts was detected in contact with dentine. After 5 days, the odontoblasts were observed beneath the dentine, and CD90-immunoreactive cells were localised under the odontoblast layer. Immunofluorescence showed co-localisation of CD90 and nestin was detected after 3 days. After 5 days, CD90-immunoreactivity increased at the subodontoblastic layer. mRNA expression of CD90 and DSPP decreased after cavity preparation, and gradually recovered (P < 0.01). These results suggest that CD90-immunoreactive cells in the subodontoblastic layer contribute to regeneration of odontoblast and subodontoblastic layers following cavity preparation.