Since the American Dental Association adopted “pulpal regeneration” as a treatment modality in 2011, regenerative endodontics has gained increasing attention to provide a biologically based treatment and promote root maturation in immature necrotic teeth. Kim et al from Columbia University, New York, explored the biological basis and clinical protocols currently used
in regenerative endodontic procedures to determine future directions in pulp and tooth regeneration.

By healing and preventing apical periodontitis, regenerative endodontic procedures might provide a tooth with a longer life span. In addition, these procedures may allow a tooth to regain the essential physiological functions, such as immune defense and tissue homeostasis.

Today, the “triad of tissue engineering” is comprised of
• scaffolds
• stem cells
• signaling molecules

Scaffolds are 3-dimensional physical structures. They provide structural and biological support‘ for the cellular activities that are involved with tissue regeneration.

Stem cells have the characteristics of self-renewal and differentiation into multiple cell lineages, and can participate in the regenerative process by being part of regenerated tissues
and/or releasing trophic factors to modulate the cellular activities in the surrounding tissues. The main stem cell sources for pulp and dentin regeneration include

• dental pulp stem cells
• stem cells of the apical papilla
• stem cells from human exfoliated deciduous teeth
• stem/progenitor cells from inflamed human dental pulp

Additionally, a patent blood supply is necessary for regeneration to occur. The regeneration of blood vessels (vasculogenesis/angiogenesis) occurs after the 3 tissue-engineering factors
play their roles.

In immature permanent teeth with pulp necrosis, revascularization/regenerative endodontic therapy has become a preferable treatment option over apexification. Thickening of the canal walls and/or continued root development, although not always predictable after regenerative procedures, is considered the desirable outcome, because it may strengthen the root and increase the
root/crown ratio.

Elimination of symptoms and healing of apical periodontitis is the primary goal of all endodontic treatment. Achieving this outcome has been shown to be very predictable after regenerative endodontic therapy of immature teeth with necrotic pulps. Achieving thickening of the canal walls and/or continued root development after regenerative procedures, root maturation and apical closure has been less predictable.

 

Conclusion

Regenerative endodontics represents a new era in biological and clinical endodontics. Although this biologically based treatment is still in its early stages, regenerative endodontic therapy may become a clinical reality in the near future because of rapid advances in pulp tissue engineering/pulp tissue regeneration research.

Kim SG, Kahler B, Lin LM. Current developments in regenerative endodontics.
Curr Oral Health Rep 2016;doi: 10.1007/s40496-016-0109-8.