Pulp-dentin regeneration: current approaches and challenges

Abstract

Regenerative endodontic procedures for immature permanent teeth with apical periodontitis confer biological advantages such as tooth homeostasis, enhanced immune defense system, and a functional pulp-dentin complex, in addition to clinical advantages such as the facilitation of root development. Currently, this procedure is recognized as a paradigm shift from restoration using materials to regenerate pulp-dentin tissues. Many studies have been conducted with regard to stem/progenitor cells, scaffolds, and biomolecules, associated with pulp tissue engineering. However, preclinical and clinical studies have evidently revealed several drawbacks in the current clinical approach to revascularization that may lead to unfavorable outcomes. Therefore, our review examines the challenges encountered under clinical conditions and summarizes current research findings in an attempt to provide direction for transition from basic research to clinical practice.

Keywords: Regenerative endodontics; pulp regeneration; revascularization; tissue engineering.

Figure 1.

Schematic illustration of revascularization procedure. Revascularization is considered for immature teeth with open apices, pulp necrosis, and apical periodontitis (a). After accessing the opening (b), gentle irrigation limited to coronal part of the chamber is performed. A radiograph with K-file insertion (c) provides the approximate tooth length, which helps to determine a working length. Low concentration of NaOCl (1.5 or less than 3%, 20 mL/canal, 5 min) is used for disinfection (d), following which saline or 17% EDTA is used. After copious irrigation and canal drying with paper point (e), intracanal medicaments, such as Ca(OH)₂ or TAP were placed, and covered with temporary filling material (f). After confirming the absence of any signs of infection, the final step is initiated. Final irrigation is performed with sterile saline and 17% EDTA (g). After the canal has dried (h), a pre-curved K-file is introduced 2 mm past the apical foramen and rotated to induce bleeding (i). Blood fills the canal from the bottom and the blood clot can be identified after 15 min (j). After the blood clot is confirmed, capping materials such as MTA are placed over the blood clot (k). Regeneration of pulp-dentin leads to root development with thickening, lengthening, and apical closure, as well as maintenance of tooth vitality (l).