3D Printed Smart Braces with Flexible Batteries and LEDs Can Improve Efficiency of Orthodontic Alignment

Every time I come across a picture of myself from the tender ages of 14 to 16, I cringe a little – not because of my questionable fashion choices, but because of those most hated orthodontic devices so many teenagers are subjected to when they least want. I am, of course, talking about braces. But now, researchers from King Abdullah University of Science and Technology, better known as KAUST, are using 3D printing technology to improve the efficiency of braces – meaning less time and cost for realigning and straightening teeth.

Each tooth has its own near-infrared LEDs to provide localized light therapy.

The dental industry has adopted 3D printing technology at a dizzying rate, and 3D printed orthodontic aligners, dental scaffolds, dental surgery drill guides, and specialized 3D printing dental resins abound – an enterprising undergrad student even made his own 3D printed orthodontics to correct his crooked teeth.

But the KAUST researchers have developed an orthodontic system that uses smart 3D printed braces and flexible, non-toxic batteries. The system consists of a semitransparent, 3D printed dental brace that places two near-infrared LEDs on each tooth, along with one lithium-ion battery to power the LEDs, which provide localized light therapy to the teeth.

But wait – putting batteries in a person’s mouth can’t possibly be safe, can it?

“We started embedding flexible LEDs inside 3D-printed braces, but they needed a reliable power supply. After the incidents with the Samsung Galaxy 7 batteries exploding, we realized that traditional batteries in their current form and encapsulation don’t serve our purpose,” explained KAUST researcher Professor Muhammad Hussain. “So we redesigned the state-of-the-art lithium-ion battery technology into a flexible battery, followed by biosafe encapsulation within the braces to make a smart dental brace.”

Bone regeneration can be increased with phototherapy, which decreases the cost and time typically involved with orthodontia. So the KAUST researchers knew they had to figure out a way to make the batteries work.

To remove the silicon substrate on the back of the battery, they bombarded it with ions in what’s known as a dry-etching technique. This made the battery flexible, and much thinner, but tests showed that its volumetric energy (ratio of energy to size of device) was still high. Now the batteries would be safe to use for powering the LEDs, which dentists can program to offer localized phototherapy specific to each individual tooth. To prevent any possibility of leakage and make them even safer, the batteries are also enclosed in soft, biocompatible polymeric materials.

Led by Professor Hussain and KAUST PhD student Arwa Kutbee, the researchers recently published a study on their unique system, titled “Flexible and biocompatible high-performance solid-state micro-battery for implantable orthodontic system,” in the Flexible Electronics journal; co-authors include Kutbee, Rabab R. Bahabry, Kholod O. Alamoudi, Mohamed T. Ghoneim, Marlon D. Cordero, Amani S. Almuslem, Abdurrahman Gumus, Elhadj M. Diallo, Joanna M. Nassar, Aftab M. Hussain, Niveen M. Khashab, and Professor Hussain.

The abstract reads, “To augment the quality of our life, fully compliant personalized advanced health-care electronic system is pivotal. One of the major requirements to implement such systems is a physically flexible high-performance biocompatible energy storage (battery). However, the status-quo options do not match all of these attributes simultaneously and we also lack in an effective integration strategy to integrate them in complex architecture such as orthodontic domain in human body. Here we show, a physically complaint lithium-ion micro-battery (236 μg) with an unprecedented volumetric energy (the ratio of energy to device geometrical size) of 200 mWh/cm³ after 120 cycles of continuous operation. Our results of 90% viability test confirmed the battery’s biocompatibility. We also show seamless integration of the developed battery in an optoelectronic system embedded in a three-dimensional printed smart dental brace. We foresee the resultant orthodontic system as a personalized advanced health-care application, which could serve in faster bone regeneration and enhanced enamel health-care protection and subsequently reducing the overall health-care cost.”

Smart dental brace system. (a) Average minimalist radius of curvature can be obtained in dental arch is 10 mm. (b) Flexible battery module bonded to aluminum interconnects on PET substrate and its integration with chip-scale LEDs. The device is embedded in a 3D printed brace with battery and LED module, repeated per each tooth. (c) Near-infrared LEDs integrated with flexible batteries and interconnected on a soft PET substrate. The whole device is embedded in semi-transparent 3D printed brace. (d) Flexible battery powering near-infrared two LEDs connected in series. (e) Image of the smart dental brace device on artificial teeth. (f) Top view of smart dental brace from the outside (left) and inside (right) with packaged red light therapy module.

As a biocompatibility test, human embryonic kidney cells were cultured over several days on the redesigned batteries. The cells multiplied, and the electrochemical performance of the batteries actually “increased linearly” as the temperature rose up to 90°C, meaning that they were stable in the environment.

Professor Hussain explained that their preliminary 3D printed brace system prototype is “more than a proof of concept,” but not ready to go on the market just yet. Seeing how the system holds up during clinical trials will be the next step of the process. The best thing about the 3D printed brace system is that it’s removable – the batteries have to be recharged sometime, so those suffering the horror of orthodontia can actually get a break for a little while.

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