The effect of intentionally perforating the floor of the pulp chamber on pulpal healing after tooth replantation in mice

Objectives: Shortening the root of a mouse molar prior to tooth replantation results in early revascu-larization in the pulp cavity and activation of the dental pulp quiescent stem cells. This study aimed to validate the effects of pulp chamber floor perforation on pulpal healing after tooth replantation as a strategy to promote early revascularization into the pulp.Methods: The maxillary first molars of three-week-old Crlj:CD1 mice were extracted and repositioned into the original socket: the left teeth were immediately replanted (control group: CG), whereas the floor of the pulp chamber of the right teeth was perforated with a tungsten carbide bur before tooth replantation (experimental group: EG). The samples were collected from three days to eight weeks postoperatively. In addition to the TUNEL assay, immunohistochemistry for Nestin, CK14, and Ki-67 was conducted. Results: In the EG, early revascularization occurred with a decrease in apoptosis and an increase in cell proliferation, facilitating pulpal healing, compared with the CG. The rate of Nestin-positive perimeter in the distal root significantly increased on days 5 and 14 and the amount of Nestin-positive hard tissue increased on day 14. However, on day 7, the number of epithelial cell rests of Malassez in the EG significantly decreased, making the EG susceptible to ankylosis at the floor.Conclusions: Intentionally perforating the floor of the pulp chamber provides a route for early revas-cularization, resulting in better pulpal healing after tooth replantation.(c) 2023 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.

Automated summary

This study aimed to validate the effects of pulp chamber floor perforation on pulpal healing after tooth replantation, and results showed that perforation can promote early revascularization and improve pulpal healing.