Implantation of odontoblast progenitors in pulp leads to neodentin formation

Stem cells have been described in the human dental pulp. Ectopic implantation of these cells led to a formation of dentin-like mineralized tissue but their capacity to readily contribute to the formation of dentin, in an injured teeth has never been explored. The aim of this study was to evaluate the feasability of a cellular therapy for dentinal injury by implantation of pulpal precursor cells into a rat maxillary molar pulp in order to induce their differentiation and the neosynthesis of a dentin-like tissue.

Methods:

The implanted cells were clonal dental pulp progenitors isolated from the first molar of ED 18 mouse embryo. These cells can be recruited alternatively towards the odonto/ osteoblast, chondrogenic or adipogenic programs depending on the type of induction and thus behave as a multipotent progenitor in vitro.

Rats were randomized in two experimental groups: 1) controls, where only the tooth cavity was performed 2) treated, where odontoblast progenitor cells were implanted in the cavity.

Results:

One month after cell implantation, the injured pulp horn appeared entirely filled with a dentine-like neostructure while the residual pulp kept its vitality.

Conclusions:

These results suggest that implantation of pulpal progenitor cells in a dentinal cavity can promote dentinal repair, while maintaining pulp vitality. Future prospects will focus on 1) identifying the cells performing this task 2) understanding the cellular and molecular mechanisms involved and 3) analyzing the structure of the neosynthesized matrix.