The healthy root pulp, degradation and regeneration

Abstract

Beneath the cell free and cell rich zones of peripheral layers, the dental pulp includes a series of healthy cells, surrounded by a ground substance forming a framework in support of a fibrous and non-fibrous extracellular matrix. Tubular dentin constitutes the outer layers, covering both the crown and root(s) parts of the teeth. The pulp includes cells that are producing structural fibers (e.g. collagens), and adhesive molecules such as glycosaminoglycans and proteoglycans, fibronectin, membrane lipids (phospholipids and proteolipids) and enzymes (e.g. metalloproteinases and specific inhibitors). Degradation of the root canal pulp is mostly due to proteinases, especially when they are activated by cariogenic bacteria. Vascular and nerve networks promote blood supply, a structure implicated in the tissue repair, releasing bioactive substances producing pain. Stem cells are recruited to heal the wounded pulp tissue. In case of defective stem cell colonies, induced pluripotent stem cells (iPS) allow the regeneration of the dental pulp. Inflammatory and immunocompetent cells contribute to the repair and regeneration of the pulp. Non-carious and carious pulp degeneration contribute to radicular pulp healing under the control of implantated growth factors, together with or without adapted scaffolds.