There's not a whole lot to like about fillings, what with the prodding, scraping and jabbing and all. And that's before the drill even comes out (followed by the bill at the end). Tending to our cavities might one day be a much more comfortable experience, with scientists discovering that a type of Alzheimer's drug can actually stimulate stem cells within the tooth pulp to promote natural repair instead.

The drug in question is a small molecule called a glycogen synthase kinase (GSK-3) inhibitor. GSK-3 is an enzyme that has been linked with a number of diseases including cancer, bipolar disorder and Alzheimer's, so molecules currently under development that inhibit its activity could one day play an important part in treatment of such conditions.

Now, scientists at King's College London have found that such inhibitors could have a role in maintaining pearly whites, too. Their research focuses on a signaling pathway called Wnt/β-cat, which is activated as an early response to tissue damage, and is thought to be critical for driving cellular-based repair in all tissues. By further promoting its activity in teeth, the team believes that they can enhance their self-repairing capabilities.

"The inhibitor activates a signaling pathway that stimulates stem cells in the tooth to make specialized cells that carry out the repair," Paul Sharpe, lead author of the study, tells New Atlas.

More specifically, it stimulates the stem cells in the tooth pulp. Normally, when a tooth suffers an injury and the soft inner pulp is left exposed, infection can soon follow. But our body has a natural defense against this, producing a thin band of tough, protective dentine that seals away the tooth's insides. It is only when a cavity is too large that dentists have to intervene with their spinning bits and artificial cements.

In their experiments, the team used biodegradable collagen sponges to apply small doses of three different types of GSK-3 inhibitors to teeth. Over time, the sponge would gradually degrade with the newly formed dentine taking its place, effectively filling in the larger cavities in a way that mimics natural repair.

This treatment could have a few benefits over traditional fillings, aside from simply the comfort factor. Fillings can be susceptible to infections or become dislodged and need replacing. And this often requires the dentist to remove and fill an area that is larger again, eventually leading to a full tooth extraction down the track. And also, because the cement never deteriorates, it alters the tooth's natural mineral levels.

The road to clinical use doesn't appear as bumpy or long as it might otherwise be. Collagen sponges are commercially available, and one of the GSK-3 inhibitors tested, Tideglusib, has already been investigated in clinical trials of neurological disorders, while the other two have "been extensively used experimentally," the researchers write.

"The simplicity of our approach makes it ideal as a clinical dental product for the natural treatment of large cavities, by providing both pulp protection and restoring dentine," says Sharpe. "In addition, using a drug that has already been tested in clinical trials for Alzheimer's disease provides a real opportunity to get this dental treatment quickly into clinics."

The research was published in the journal Scientific Reports.

Source: King's College London