Tooth Repair and Regeneration

Abstract

Purpose of review: Current dental treatments are based on conservative approaches, using inorganic materials and appliances.This report explores and discusses the newest achievements in the field of "regenerative dentistry," based on the concept of biological repair as an alternative to the current conservative approach.

Recent findings: The review covers and critically analyzes three main approaches of tooth repair: the re-mineralization of the enamel, the biological repair of dentin, and whole tooth engineering.

Summary: The development of a concept of biological repair based on the role of the Wnt signaling pathway in reparative dentin formation offers a new translational approach into development of future clinical dental treatments.In the field of bio-tooth engineering, the current focus of the researchers remains the establishment of odontogenic cell-sources that would be viable and easily accessible for future bio-tooth engineering.

Keywords: Bio-tooth; Biological repair; Dentinogenesis; Regenerative dentistry; Reparative dentin.

Fig. 1

Schematic representation of different approaches for dentine-pulp complex repair/regeneration (a) and stem-cell-based whole-tooth bioengineering (b). a Pharmacological modulation of Wnt/β-catenin signaling pathway shows natural dentine apposition in both, deep cavitation without pulp exposure (reactionary dentine, upper left box) and cavitation with exposed pulp tissue (reparative dentine, upper right box), as long as the underlying pulp tissue is vital and harbors resident odontoblasts and dental pulp stem cells (DPSCs) respectively. The simple applicability of this technique by using a drug-enriched collagen sponge makes it ideal for a translational clinical treatment approaches. In case of pulp infection and necrosis (lower right box), current therapies include orthograde root canal treatment or, in selected cases with incomplete root formation, revascularization procedures. Recent cell-based approaches show that autologous isolated, expanded, and mobilized DPSCs have the capacity to re-innervate (positive response on pulp testing) a pulpectomized and disinfected tooth after auto-transplantation; however, this approach is highly technique sensitive and might remain in facilities with specialized equipment and laboratories for selected cases only. Non-cell-based approaches for mimicking lost enamel-structure exists (lower left box) yet the mineralization potential of self-assembling peptides needs to be further evolved and clinically tested. b Suitable adult sources of epithelial and mesenchymal cells are collected from the patients with missing teeth and expanded in vitro. Either epithelial or mesenchymal cell populations are induced to be odontogenic (capable of initiation of de novo odontogenesis) and recombined with the responsive cell population counterpart. An early-stage tooth primordium can be generated from the epithelial-mesenchymal-cell recombination, which can be subsequently either directly transplanted at the location of the missing tooth or cultured ex vivo to form a whole tooth to replace the missing tooth