Of all the dreaded dental appointments, root canal procedures rank among the most cringe-worthy. In fact, so many people loathe the dentist’s chair that one-third of US adults skip their annual appointment and more than one-quarter have untreated tooth decay.

Now, scientists from Temple University hope to lessen that worry, at least when it comes to root canals. Their study used a two-sided scaffold and dental stem cells to guide the growth of dentin and pulp tissue, including the blood vessels and nerves. 

Root canal therapies are performed when the pulp in mature teeth becomes infected or damaged. To resolve this, dentists remove the diseased tissue, clean the inside of the tooth, and seal it. There are around 15.1 million root canal procedures per year, according to the American Association of Endodontists.

“When we see patients, most have the pulp infected, so the nerve has to be taken out,” said Maobin Yang, associate professor of Endodontology and director of the Regenerative Health Research Laboratory, in a statement. “The root canal is then empty, so we currently fill up the root canal with inert treatment.”

However, simply regenerating this tissue with stem cells is not so easy. If the stem cells are haphazardly placed in the root canal, they won’t know where to grow the pulp and where to grow the dentin. This is a crucial step: The dentin must be on the outside and the pulp on the inside. To ensure this correct arrangement, the team constructed a bilayered scaffold to guide the cells’ growth, one that could mimic the closed and porous nature of dentin and pulp, respectively. 

“The beauty of the system is that we have shown in vitro [test tube] that we can engineer a two-sided scaffold, and can guide the stem cells to differentiate into both pulp cells and dentin, producing odontoblasts that will eventually repair the root canal,” said Professor Peter Lelkes, department chair of bioengineering, in a statement. “We – our smart scaffold – can do this differentially with great efficacy.”

The findings, published in the journal Tissue Engineering, may be particularly useful for immature teeth. That’s because root canals are best suited for patients with mature, permanent teeth. Those with immature teeth have thin dentin walls and incomplete root development, making conventional therapies difficult. For these individuals, regenerative tissue therapy provides an alternative treatment with possibly better outcomes.

For practical application, the team say they envisage the scaffold rolled into a tube and inserted into the root canal. The porous side would face the inner lumen for soft pulp tissue regeneration and the closed side would face the existing dentin.

The research is not fully formed yet, and the ability to grow entire teeth is still a conundrum. The team’s next step is to test their findings in animal models.

“I believe in the next 10 years, or even sooner, when patients come to the endodontist for a root canal treatment, we will be able to provide an alternative, equivalent or even better treatment modality, which is to regrow the nerves and the blood vessels and to grow new pulp back into your tooth, instead of using inert material,” Yang said. “With investments and with lots of research, I believe that we will get there soon.”