Researchers are working towards the ability to regenerate the dental pulp inside teeth. Full regeneration of teeth has seemed perpetually on the verge of success for a decade or so now; it has been achieved as a proof of concept in rats, for example. Restoration of dental pulp is a more viable, less complex project, given the present state of research into the use of scaffolds to provoke regrowth.
Researchers have proposed an alternative to root canals in dentistry: restoring the lost tissue in the tooth cavity by inducing the body to regenerate it. Their goal is to develop a materials-based therapy that does not contain live cells and therefore could be sold off-the-shelf. It would be the first of its kind. The team has created an injectable hydrogel designed to recruit a person's own dental pulp stem cells directly to the disinfected cavity after a root canal. Composed of biocompatible peptides that aggregate into fibers, the hydrogel delivers biological cues to direct tissue growth, as well as a scaffold structure to support it.
A procedure known as over-instrumentation is performed on children's immature permanent teeth with necrotic pulp, prompting new growth of the still-forming root by eliciting a healing response. The tissue outside of the emptied canal, when poked, forms blood clots that secrete a growth factor that signals cells to produce new tissue to support the root. While some regrows, it is disorganized, lacks the needed tissue differentiation - including nerve cells - and fails to mimic soft tissue. By contrast, the team's hydrogel therapy mimics the body's own growth factor signaling, and, coupled with known antimicrobial mechanisms engineered into those materials, is capable of promoting tissue healing and regeneration.
In early animal studies, dogs injected with the team's hydrogels formed soft tissue from the tooth apex to the crown in just under a month. "We saw a lot of different tissues, including blood vessels, nerve bundles and pulp-like cells. One of the primary goals of this project is to determine the type of cells that reorganize and repopulate the regenerated tissue." One of the core challenges tissue engineers face is creating blood vasculature, the plumbing that delivers nutrients to regenerated cells. To address the problem, the team's hydrogel contains a protein known as vascular endothelial growth factor that stimulates the growth of new blood vessels.