When cavities appear on the visible surfaces of teeth, they are relatively easy for dentists to spot. But for cavities between teeth, especially in the back of the mouth, dentists typically rely on X-rays. X-rays can only reveal cavities after about 30% of the enamel in a certain area has been damaged.
Gili Naveh, associate professor of orthodontics at the Tufts University School of Dentistry and associate professor of biomedical engineering in the School of Engineering, has designed a simple tool called CaviSense to help dentists and patients find cavities between teeth before they show up on X-rays.
By catching cavities early, dentists can effectively treat and reverse any damage without drilling or fillings.
“Every tooth you drill into — the restoration you make — is not for life. It will eventually fail, and you need to replace it and do a larger restoration,” Naveh said. “If we can detect cavities early and prevent drilling, we can extend the life of the tooth.”
After practicing dentistry for about six years, Naveh returned to school to earn a doctorate in structural biology, followed by a postdoctoral fellowship and an advanced degree in orthodontics. She is now a practicing orthodontist and scientist.
In her lab, she typically studies the structure and function of the periodontal ligament (the ligament that connects the teeth to the jaw), looking for ways to reverse the effects of gum disease and improve orthodontic treatment.
Basic science research like this is critical, but it often takes a long time to translate into tangible benefits for patients. When the parents of an orthodontic patient expressed their frustration with the number of fillings their child needed, Naveh saw an opportunity to design a solution that could help the patient more quickly.
“They had tried everything the pediatric dentist had told them, but every time they went to the dentist, the dentist would find a lot of new cavities,” Naveh says. “They told me, ‘If we could do a test at home to see when these early cavities start, then we could keep up with the dentist visits and not fill three to five teeth each time.’”
The tools these parents were waiting for weren’t available yet, but Naveh had come up with a way to detect cavities before they were visible on an X-ray.
Tooth decay is caused by harmful bacteria that colonize teeth. These bacteria consume sugars, produce acids, and cause tooth enamel to dissolve—a process called demineralization—which, if left untreated, can eventually lead to cavities.
Demineralization begins when the pH level on the surface of a tooth drops below 5.5 (our mouths are typically fairly neutral, with a pH of around 7), so Naveh designed the CaviSense toothpick to detect when acidity exceeds that threshold.
Before using the CaviSense toothpick, patients eat a sugary gummy. Any bad bacteria on the teeth quickly begin digesting those sugars and secreting acid. A dentist or parent can then insert the thin, flat tip of the toothpick between teeth or anywhere they’re concerned about possible cavities.
If the tip of the toothpick changes color from purple to yellow, that indicates the pH level in that area is below 5.5—acidic enough to dissolve tooth enamel.
“It’s inexpensive, easy to use, and very intuitive,” Naveh says. “Both the dentist and the patient can see the surface between the teeth that is demineralizing, and some patients appreciate the fact that they can see it firsthand.”
If a dentist catches a cavity early, a filling isn’t always necessary. In fact, in some cases, decay can be reversed with a remineralization treatment. The dentist removes the bacteria and applies a mineral-rich paste to the decayed area to help the enamel solidify again. The process is simpler, cheaper, and more comfortable for the patient than a filling.
“No drilling, no filling, no anesthesia—you just put a little polish on the tooth and let it do its job,” Naveh says. “It’s good for everyone.”
Naveh began designing the CaviSense toothpick in her lab and helped found a startup last year to bring it to market. She and her colleagues at CaviSense have been working with pediatric dental offices to add CaviSense to their workflow and ensure its practicality.
The toothpick is also available for people to use at home and comes with an app to help users record and interpret the results. People can buy five toothpicks for $25 on the CaviSense website.
The CaviSense toothpick is designed primarily to detect cavities between teeth, but Naveh and her colleagues know that some parents would like to be able to check all tooth surfaces at home (which would require a lot of toothpicks).
She and her colleagues are designing a simpler at-home test that uses a fillable tray that patients bite down on to test all tooth surfaces simultaneously. The filling material has the same color-changing properties as the CaviSense toothpick, so any problematic spots will turn yellow on the impression.
The researchers are in the final stages of prototyping and plan to start collecting feedback from dentists soon. They hope to have the new cavity tester available to the public by mid-2025.
“We can allow people to test themselves for cavities at home and then see a dentist in time to stop cavities or even cure them,” Naveh says. “Everyone will be happier—kids, parents, and even dentists because they can provide faster, better treatments and help more patients.”
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