Regenerative endodontics uses the concept of tissue engineering to restore the root canals to a healthy state, allowing for continued development of the root and surrounding tissue.
Endogenous stem cells from an induced periapical bleeding and scaffolds using blood clot, platelet rich plasma or platelet-rich fibrin have been utilized in regenerative endodontics. This approach has been described as a 'paradigm shift' and considered the first treatment option for immature teeth with pulp necrosis. Endodontists’ knowledge in the fields of pulp biology, dental trauma, and tissue engineering can be applied to deliver biologically based regenerative endodontic treatment of necrotic immature permanent teeth resulting in continued root development, increased thickness in the dentinal walls thereby increasing fracture resistance, revitalization of the tooth and apical closure.
The promise and potential of regenerative endodontic therapies in necrotic teeth was first explored by Nygaard-Östby in 1961 who investigated the potential for repair when bleeding was induced by over-instrumentation beyond the apex prior to partial root filling of the canal with limited success. This is an important step by the endodontic community on its path to explore avenues of pulp and dentin regeneration.
The clinical considerations for regenerative endodontic protocols are:
(1) disinfection of the root canal system
(2), provision of a scaffold which often involves laceration of the periapical tissue to induce a blood clot and introduce stem cell activity within the root canal
(3), and an adequate coronal seal to prevent reinfection. These developments in the regeneration of a functional pulp-dentin complex have a promising impact on efforts to retain the natural dentition, the ultimate goal of endodontic treatment.
Currently, this biologically based treatment is being recognized as the first treatment choice for immature teeth with pulp necrosis based on the success of many published cases in the literature. Our understanding of the clinical protocols has evolved to eliminate pulp infection and to also allow for stem cell potential to be induced in the canal and for the release of growth factors fossilized in the dentine walls. While repair rather than true regeneration is achieved with current protocols, it is hoped that further research in the area of stem cell-based pulp engineering will allow for true regeneration and improved treatment outcomes.