Immunohistochemical analysis of pulpal regeneration by nestin expression in replanted teeth

Aim To investigate dental pulp healing after tooth replantation in rats using nestin as an odontoblastic marker for immunohistochemical analysis. Methodology Twenty-five maxillary right first molars from 25 female Sprague-Dawley rats, aged 4weeks post-natally, were extracted and immediately repositioned in the original socket within 5s. Five rats each were later killed on days 3, 5 and weeks 1, 2 and 4. The maxillae were removed en bloc and the tissue samples containing the maxillary right first molars were decalcified, sectioned, mounted and stained with anti-nestin antibody to be observed under a light microscope. Results At 3days after replantation, there was a localized inflammatory reaction, but pulp revascularization and healing had begun in the root area. At 5days after replantation, odontoblast-like cells were observed. Reparative dentine deposition was observed beneath the pulp-dentine border from 1week after replantation, and gradually increased until 2weeks after replantation. The presence of odontoblast-like cells and the formation of reparative dentine continued from the first week throughout the experimental period. At week four, deposition of osteodentine and cementum-like tissues were observed. Conclusions Pulpal mineralization after replantation initially occurred via the deposition of reparative dentine, followed by the deposition of osteodentine and cementum-like tissues in rat teeth.