Sensitive Teeth


Forget diets and food diaries to keep track of what you eat on a daily basis.

Tufts University researchers have developed a tooth sensor sticker that can track glucose, salt and alcohol – wirelessly transmitting the information to a device to keep tabs on nutrition and calories.

The 2mm by 2mm flexible sensor can bond to a tooth’s minutely bumpy surface and has three layers: two outer gold rings and an inner layer of a bio-responsive material that’s sensitive to glucose, salt and alcohol. These substances shift the material’s electrical properties and cause it to transmit a different spectrum of radiofrequency waves.

Together, the three layers act as an antennae, broadcasting the information to mobile devices like phones or tablets.

While the material in the prototype is only sensitive to a few foods, researchers hope to develop it to detect a far wider range of chemicals and nutrients.

Research leader Professor Fiorenzo Omenetto says a database of food consumption could be located in the sensor to manage nutrition. “That could be reminding us that we’re indulging too much in sugar or something like that.”

Scientists have developed wearables for monitoring food intake before, with most in the form of mouthguards.

Japanese, American and Brazilian scientists created similar biosensors, but all required a mouthguard that was uncomfortable to wear.

Diabetics could theoretically use the new tooth-mounted sensor to monitor their sugar intake and broadcast the information to their doctors, Omenetto says. It could also be helpful for people with other medical conditions that require them to monitor their eating, such as patients with high blood pressure who need to limit their salt, or people with coeliac disease who need to completely avoid gluten.

The device could also potentially detect physiological states, like changes in saliva that signal developing gum disease.

“This study is an interesting proof-of-concept demonstration that small, wireless biosensors can detect changes in saliva due to the presence of compounds such as salt, sugar and alcohol,” says Ben Almquist, a professor of bioengineering at Imperial College London.

But, Almquist says, there will be “significant hurdles” before the technology is ready for daily use as a food diary substitute. “For instance, for continuous monitoring of food intake, the sensors will need to be robust enough to withstand abrasion during chewing. In addition, foods are complex mixtures of compounds including salts, sugars and proteins, and the relative amounts of each that enter into saliva will depend on factors such as the nature of the food, the amount of chewing, and the time in the mouth before swallowing.”

But other, less complex uses may be closer at hand, Almquist says. Detecting compounds in saliva like lactate, which is important in monitoring critical care patients, as well as athletes during training, could be simpler to achieve.

Then, there’s the critical question of aesthetics: how many people want what basically looks like a computer chip on a tooth? “It’s a bit of a leap of faith – some people may find it horrible,” Omenetto says. “You could make [devices]that are shaped like a flower or something.” The sensor could simply be mounted on a back tooth where it’s not visible.