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[Image above] BioMin Technologies has already manufactured thousands of tubes of its new bioglass toothpaste. Credit: BioMin 

People with sensitive teeth, rejoice—bioglass toothpaste is back. And it’s better than ever.

About three years ago, ACerS editor Peter Wray reported about the disappointing absence of bioglass in the U.S. formulation of Sensodyne’s Repair & Protect toothpaste.

It was so disappointing because the inclusion of bioglass in formulations of the toothpaste sold in other countries around the world had the awesome ability to effectively occlude the dentinal tubules that, when exposed, cause tooth sensitivity

Dentinal tubules become exposed when the tooth’s natural enamel is worn away, which is a common problem in mouths worldwide. The reason exposed tubules are so bad is that they provide an open mainline right to the tooth’s nerve—ouch.

While this protective enamel layer doesn’t grow back, bioglass-laden toothpaste can provide an alternative solution the problem.  

The formulation of bioglass in the Sensodyne toothpaste—commercially called NovaMin—reacts with saliva in the mouth to form a protective layer of hydroxyapatite on teeth. That layer mimics the original protective enamel, creating a barrier that prevents the jarring discomfort that is tooth sensitivity.

Although the layer isn’t permanent, continual brushing with the toothpaste can maintain a steady level of protection, providing relief to the millions of people worldwide with sensitive teeth.

However, according to Wray’s reporting, it seemed that FDA approval—or more accurately, lack thereof—was preventing the inclusion of bioglass in Sensodyne Repair & Protect in the U.S.

Although we haven’t heard any more about the fate of Sensodyne’s stateside formulation of bioglass toothpaste, there may soon be a new sensitivity-solving toothpaste on the block.

News from Queen Mary University of London reports that U.K. scientists have developed a new and improved bioglass toothpaste formulation called BioMin. In addition to addressing tooth sensitivity, BioMin’s makers say the toothpaste can also help prevent tooth decay and acid erosion, thanks to the ability of the bioglass to form a protective enamel-mimicking layer and slowly release fluoride into the mouth.

Robert Hill, professor of dentistry-related physical sciences in the Materials Research Institute at Queen Mary University of London, led the research team that developed the discovery.

Hill says he and a team of scientists began investigating their bioglass compositions back in 2006, when he was at Imperial College London. “Delia Brauer—who won the Gottardi Award last year for her work in this area—with Robert Law and myself did a lot of fundamental studies, initially using a lot of solid state nuclear magnetic resonance spectroscopy,” Hill says in an email. “But the real breakthrough came at Queen Mary at the Institute of Dentistry, where I joined up with David Gillam, a clinician who actually did the first studies on bioglass occluding dentinal tubules.”

In 2014, Hill and Gillam cofounded BioMin Technologies to commercialize their progress. BioMin Technologies has since developed several bioglass formulations, including BioMinF, a fluoride-containing bioglass that is designed and optimized for toothpaste.

But BioMin isn’t just another version of bioglass—it has some important benefits over the original NovaMin formulation.

“In addition to fluoride in the glass (of which there is relatively little), the glass has a higher phosphate content and a much lower silica content than the NovaMin/45S5 glass,” Hill says via email.

That higher phosphate content is almost three times that of NovaMin, according to the company. BioMin also contains smaller particles than NovaMin, which may help the bioglass better infiltrate dentinal tubules to plug access to the tooth nerve.

But the real magic is in the chemical formulation of the new bioglass. BioMinF slowly dissolves to release calcium, phosphate, and fluoride ions, stretching the release out over 8–12 hours for long-lasting protection.

“The particle size and the network connectivity of the glass are designed so the glass will dissolve over the time period between brushing your teeth,” Hill says.

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Scanning electron micrograph of dentinal tubules before (left) and after (right) brushing with BioMinF. Credit: Queen Mary University of London; BioMin

BioMinF especially differentiates from previous bioglass toothpastes because it forms fluorapatite, rather than hydroxyapatite, on teeth. “Fluorapatite is much more resistant to acids produced by bacteria and promotes remineralization, particularly in combination with the calcium and phosphate released from the glass,” Hill explains.

And, although many conventional fluoride toothpastes already exist, those formulations contain soluble fluoride—which, because it’s easily washed away, is ineffective within a couple of hours of brushing.

Instead, BioMin contains a polymer that binds calcium in the bioglass to calcium on the enamel, preventing the bioglass from being washed away. This innovation makes the bioglass-based protection last longer.

Slower release of fluoride also has the added benefit of BioMin toothpaste being able to use a much lower concentration of fluoride—almost one-third that of conventional fluoride toothpastes, according to the company.

Further, BioMinF is designed to dissolve more rapidly with lower pH, offering added protection when teeth are directly challenged with acidic food or drinks.

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Scanning electron micrograph of BioMin-treated dentinal tubules before (left) and after (right) an acid erosion challenge. Credit: Queen Mary University of London; BioMin

Hill says that the team has patented its innovation and holds two U.S. patents for its products. He adds, “We have freedom to operate with regard to the NovaMin patent family.”

And commercial scale-up is no barrier—the company is manufacturing its bioglass via a conventional melt quench route, which makes production economical. Hill says that BioMin Technologies has manufactured BioMinF bioglass on a ton scale and has already produced 10,000 tubes of BioMin toothpaste.

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Robert Hill pours the bioglass for BioMin toothpaste. Credit: Queen Mary University of London; BioMin

According to the press release, BioMin is already available through special distributors—it costs £4.99 for a 75 mL tube—and is expected to be available in stores in the U.K. by the end of the year.

But what about the U.S.?

According to Hill, Sensodyne Repair & Protect contained fluoride plus NovaMin, which the FDA classified as two separate active ingredients. “Fluoride is classified as a drug by the FDA, but this is generally waived for toothpastes. However, they ruled—as I understand it—that because Sensodyne Repair & Protect had two active ingredients, including fluoride, it was potentially a drug.”

BioMin, however, should fare better in U.S. markets. Hill explains that BioMinF has only one active ingredient and, technically, no fluoride—at least not until the glass starts to dissolve. But, Hill adds that this detail makes it hard to predict how the FDA will view BioMinF.

So the company has a backup plan to get its bioglass toothpaste into the American market, regardless of the outcome with BioMinF. “We have developed a chlorine-containing bioglass, BioMinC, for the U.S. market if the FDA approval of BioMinF is problematic,” Hill adds. “The chlorine glass releases chloride ions as opposed to fluoride ions and are naturally present in the body at high concentrations.”

So, it looks like the U.S. market might finally get to reap the full benefits of bioglass toothpaste. It’s about time.