A dentist frustrated by how late cavities are typically detected has invented a color-changing toothpick that could transform dental care by catching decay weeks or months before it requires drilling and filling.
The pocket-sized device, developed by a Tufts University professor with dual appointments in dentistry and engineering, allows patients and dentists to detect the earliest stages of tooth demineralization—the process that eventually leads to cavities.
“Every tooth that you drill into—the restoration that you make is never for life. It will eventually fail and you will need to replace it and make an even bigger restoration,” said Gili Naveh, associate professor of orthodontics at Tufts University School of Dental Medicine and of biomedical engineering at the School of Engineering. “If we can catch cavities earlier and prevent drilling, it will prolong the lifespan of our teeth.”
Traditional dental X-rays only catch cavities after about 30 percent of the tooth enamel has already been compromised. At that point, drilling and filling is usually the only option. Naveh’s invention, called CaviSense, can potentially identify problem areas weeks or months earlier, when simple remineralization treatments might still reverse the damage.
The device works by detecting acidity levels between teeth. After a patient eats a sugary gummy, any harmful bacteria present will begin producing acids. When the thin, flat tip of the CaviSense toothpick is inserted between teeth, it changes color from purple to yellow if the pH drops below 5.5—the threshold at which tooth enamel begins to dissolve.
“It’s cheap and it’s easy to use and it’s very visual,” Naveh explained. “Both the dentist and patient can see that there is a surface between the teeth that is demineralizing, and some patients appreciate an objective tool that they can see with their own eyes.”
The innovation stems from Naveh’s unusual career path. After practicing general dentistry for six years, she earned a Ph.D. in structural biology, completed a postdoctoral fellowship, and received an advanced degree in orthodontics. She now splits her time between clinical orthodontics and scientific research.
While her laboratory typically focuses on the periodontal ligament—the tissue connecting teeth to the jawbone—the idea for CaviSense came from a more immediate patient need. The parents of one of her orthodontic patients were frustrated that their child required multiple fillings at each dental visit despite following their dentist’s recommendations.
“They tried everything their pediatric dentist told them, but every time they would go for an exam, the dentist would find so many new cavities,” Naveh said. “They told me, ‘If we could just test at home and see when these early-stage cavities are starting, then we could get to the dentist on time instead of needing three to five fillings each trip.’”
Catching decay early not only prevents drilling but opens up gentler treatment options. “There’s no drilling, no filling, no anesthetics—you just apply some polish on the tooth and let it work,” Naveh said. “It’s better for everybody.”
Naveh founded a startup last year to bring the invention to market. The company has been working with pediatric dental practices to incorporate the tool into their workflows, and the toothpicks are now available directly to consumers. People can purchase five toothpicks for $25 on the CaviSense website, along with an app to help record and interpret results.
For parents wanting to check all tooth surfaces at once, Naveh and her team are developing an even more comprehensive solution—a fillable tray that patients bite into, which shows trouble spots through the same color-changing technology. The team hopes to make this new cavity tester available to consumers by mid-2025.
“We can enable people to test whether they have cavities from home, and then get to the dentist in time to stop cavities and even heal the tooth,” Naveh said. “Everybody will be happier—kids, parents, and even dentists because they’ll be able to provide quicker, better treatments to help more patients.”
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