Polymer-Based Instructive Scaffolds for Endodontic Regeneration

Abstract

The challenge of endodontic regeneration is modulated by clinical conditions which determine five kinds of tissue requirements: pulp connective-tissue formation, dentin formation, revascularization, reinnervation and radicular edification. Polymer scaffolds constitute keystone of the different endodontic regenerative strategies. Indeed, scaffolds are crucial for carrying active molecules and competent cells which optimize the regeneration. Hydrogels are very beneficial for controlling viscosity and porosity of endodontic scaffolds. The nanofibrous and microporous scaffolds mimicking extracellular matrix are also of great interest for promoting dentin-pulp formation. Two main types of polymer scaffolds are highlighted: collagen and fibrin. Collagen scaffolds which are similar to native pulp tissue, are adequate for pulp connective tissue formation. Functionnalization by active biomolecules as BMP, SDF-1, G-CSF enhances their properties. Fibrin or PRF scaffolds present the advantage of promoting stem cell differentiation and concomitant revascularisation. The choice of the type of polymers (polypeptide, PCL, chitosan) can depend on its ability to deliver the active biomolecule or to build as suitable hydrogel as possible. Since 2010s, proposals to associate different types of polymers in a same scaffold have emerged for adding advantages or for offsetting a disadvantage of a polymer. Further works would study the synergetic effects of different innovative polymers composition.

Keywords: active biomolecules; dental pulp; dental stem cells; endodontics regeneration; hydrogels; nanofibers; polymers; scaffolds.

Figure 1

Levels of endodontic regeneration. 1; Pulp Connective tissue Formation, 2; Dentin Formation, 3; Revascularization, 4; Reinnervation, 5; Radicular Edification. a: Enamel, b: Dentin, c: Odontoblasts, d: Pulp, e: Blood vessels and nerves, f: Root canal, g: Apex, h: Bone, i: Lesion, j: Pulp fibroblasts.

Figure 2

Polymer instructive scaffold for endodontic regeneration. Incorporation of active biomolecules inside the scaffold allows orchestration of tissue regeneration and attraction of resident cells according to ‘’cell homing process’’. Stem cells cultured in the scaffold optimize the pulp regeneration, notably matrix deposition. AB; Active biomolecules (white rounds), BV; Blood vessels, CAS; Cellular adhesion site, F; Fibroblasts, MD; Matrix deposition, MSC; Mesenchymal stem cells, N; Nerves, NF; Nanofiber.