Giving New Meaning to Sensitive Teeth

As wearable technology continues expanding into new areas of health monitoring, researchers are steadily uncovering more about the signals our bodies generate day and night. Smartwatches still dominate the consumer landscape, tracking heart rate, sleep, blood oxygen levels, and more. A smaller ecosystem of research-focused devices, like earbuds, smart glasses, and skin patches, has pushed those capabilities even further. But almost none of these technologies look to one of the most information-rich parts of the body: the mouth.

A research team at Delft University of Technology and Radboud University Medical Center aims to change that with a new intraoral sensing platform called Densor. Built into a standard dental retainer, Densor measures factors such as oral temperature, jaw movement, and whether a user is speaking or drinking water. What sets it apart is not the individual sensors themselves, but the engineering that makes long-term, safe, and practical sensing inside the mouth possible — something previous systems have struggled to achieve.

Traditional intraoral devices rely on tiny batteries that can pose safety risks and complicate fabrication. Densor instead harvests energy wirelessly using Near Field Communication (NFC), the same technology used for tap-to-pay cards and smartphone pairing. Because NFC is already built into nearly every modern smartphone, users can charge Densor and retrieve data simply by tapping their phone to their retainer. Energy is stored in compact capacitors rather than batteries, eliminating toxicity concerns.

To conserve the limited energy stored in those capacitors, Densor incorporates a low-power real-time clock that keeps the system dormant between measurements. The microcontroller and sensors power on only during brief sampling windows, a strategy that enables hours of operation with sampling intervals as short as two minutes. All collected data is stored in onboard non-volatile memory, ready to be read out by the smartphone app without waking the main processor.

Despite its tight size and power constraints, Densor integrates three sensing modalities. A three-axis accelerometer captures jaw position and head orientation during sleep. A miniature photodiode detects mouth opening by measuring ambient light entering the oral cavity. And a temperature sensor monitors oral temperature, a valuable signal often overlooked by consumer health devices. Together, these sensors form a multimodal dataset that has historically been almost impossible to gather outside of specialized clinical settings.

The entire Densor system can be embedded into a conventional orthodontic aligner using tools already common in dental labs. This simplicity, along with an estimated production cost of around $150, could accelerate adoption among clinicians and researchers.

There are many potential use cases for this technology, including monitoring patient compliance with dental treatments, improving the diagnosis of sleep disorders, studying hydration patterns, and advancing speech therapy. None of these measurements are new to science, but collecting them safely, comfortably, and continuously inside the mouth is, and that could make Densor a very desirable tool in the years ahead.