Fig. 5.

Regenerative endodontic treatment approaches. a Revitalization is the process of inducing apical bleeding by which cells are brought into the root canal. b In the idea of in situ tissue engineering cells are expanded ex vivo and transplanted into the root canal with a scaffold. c Cell homing, on the other hand, is a primarily cell-free approach that makes use of locally available cell sources. A custom-made scaffold with biomolecules is placed in the canal and cells migrate from the periapical tissues. d This concept is also applicable if there is residual pulp tissue in the root canal, which in this case serves as cell source and is, thus, expanded