Somewhere in the records of U.S. patents lies a design for an artificial tooth containing a power generator inside it.
Two engineers from the headset manufacturer Plantronics, Thomas Trumbull and Timothy Johnston, submitted a patent for a Jaw powered electric generator in May 2012, receiving approval three years later. Their innovation divides a synthetic tooth into two segments. One section is fixed to the jawbone, while the other is slightly movable, and a piezoelectric component is positioned in the space between them. Biting compresses this component, and the pressure is converted into electrical current, which is managed by a rectifier circuit and stored in a miniature battery.
Plantronics producers Bluetooth headsets, so the rationale is easily understood. Devices continue to shrink and increasingly demand a power source, and the patent’s background section laments the burden of carrying extra batteries and chargers. An energy-storing tooth during meals resolves this issue in the most straightforward manner possible.
Transforming pressure into electricity
Piezoelectricity derives its name from the Greek word meaning pressing. Certain ceramics and crystals feature uneven internal arrangements that deform under pressure, leading positive charges to relocate to one side and negative to the opposite. When released, the effect reverses. This operates similarly to the click produced by a barbecue igniter.
The jaw represents a promising site for this application. It closes many times throughout a meal with substantial force, yet none of that energy currently contributes anything beyond breaking food down.
Why the results are underwhelming
“The power output we achieved is far from adequate,” Aidin Delnavaz, who collaborated on the most functional prototype, communicated to New Atlas. He and Jérémie Voix from Montreal’s École de technologie supérieure integrated piezoelectric fiber composites into a helmet chin strap and had test subjects chew gum, as discussed in a study published in Smart Materials and Structures. Their apparatus generated approximately 10 microwatts during typical usage and up to 18 at peak performance.
This should be compared to the maximum potential. The average mechanical energy produced from chewing is about seven milliwatts, meaning the strap managed to capture a tiny fraction of a percent of what an operational jaw generates.
Eighteen microwatts is insufficient to power a phone, a watch, or any device with a display.
Delnavaz’s proposed solution, in comments released by IOP Publishing, was brute force: stack 20 layers of the composite, each six millimeters thick, enough to power a 200-microwatt hearing protector.
The prototype that reached the lab
Chewing power proves more effective when the goal is something that remains within the mouth. Geelsu Hwang at the University of Pennsylvania School of Dental Medicine has been developing a crown made from dental resin infused with barium titanate nanoparticles, a project described by Penn Today. Chewing and brushing the teeth stimulate the particles, generating charge to energize a ring of near-infrared micro-LEDs located at the crown’s base. This light assists in treating gum tissue, which frequently becomes inflamed and endangers the implant’s survival.
Hwang received a $2.6 million grant from the National Institutes of Health to explore its antibacterial properties and advance towards testing on mini pigs.
A tooth that communicates
When applying pressure with one of these implants, the tooth senses it as well. Researchers at Huazhong University of Science and Technology 3D-printed an implant incorporating a piezoelectric core composed of barium calcium zirconate beneath a ceramic crown, converting biting force into an electrical signal conveyed by the jaw’s nerves to the brain. Traditional implants lack this sensory feedback, which is why individuals with them often bite too forcefully, damaging the adjacent teeth.
Twenty-three participants at the university hospital tested it. As detailed by