Scientists aim to regrow teeth using stem cells

No more painful root canals?
Scientists are close to developing a new and effective way to treat tooth decay that fully restores the tooth rather than requiring it to be filled, capped or extracted.
The method, which uses stem cells, could prove especially useful in treating the kinds of cavities leading to most dreaded and painful procedure - the root canal.
"Generally we treat deep cavities by capping the tooth and removing any inflamed pulp surrounding it. But this has limited success and the problem frequently progresses until the tooth must be removed" said Misako Nakashima, of the National Center for Geriatrics and Gerontology in Obu, Japan.

In the study, the goal of researchers was to test a stem cell-based therapy that would regenerate the dentin-pulp complex and, consequently, totally restore the tooth's structure and function.
At the same time, researchers wanted to assess the safety of pulp stem cell transplantation in humans as a prelude to upcoming clinical trials.

They began by performing root canals on a group of 18 dogs, collecting the pulp stem cells and then treating them in the lab with a growth factor called granulocyte-colony stimulating factor (G-CSF).
They then transplanted the treated cells back in the dogs, with each animal receiving its own cells to reduce the chance of rejection.

When they examined the results, which included comparing the G-CSF treated cells to a control group of non-treated cells, they found the cells did indeed regenerate the pulp tissue and completely filled in the dogs' root canals.
"We also noted that the pulp stem cells treated with G-CSF yielded a significantly larger amount of regenerated dentin-pulp complex than those without it," Nakashima said.
"Also noteworthy was the reduced number of inflammatory cells, the decrease in cell death and the significant increase in neurite outgrowth (the projections that transfer a cell's impulses compared to those without G-CSF). Furthermore, there was no evidence of toxicity or adverse events," said Nakashima.

Based on these pre-clinical results of efficacy and safety, a clinical trial of pulp regeneration has already been initiated, she added.
The findings were published in the journal STEM CELLS Translational Medicine.