A better brush

A new product developed from technology invented at the University of Washington (UW) aims to change the way you brush your teeth.

It will make ultrasound – now available only at the dentist – part of the daily routine. The high-tech brush creates vibrations in bubbles of foam that work to clean pearly whites.

The story of the Ultreo toothbrush, as the product is now known, began in 2003, when the UW’s Pierre Mourad met local entrepreneur Jack Gallagher for lunch.

Mourad, a research scientist in APL’s Center for Industrial and Medical Ultrasound and research associate professor in the UW’s Department of Neurological Surgery, was using high-frequency pulses to deliver drugs to brain tissue and to diagnose pain. Mourad sought an investor for a medical company. Gallagher, who helped launch the Sonicare toothbrush, had another idea: He wanted to build a better toothbrush.

Mourad knew that ultrasound, already used in high-pressure professional dental cleanings, could clean teeth. The technique works because ultrasound is the right frequency to vibrate bubbles. As the bubbles vibrate more than 20,000 times per second, they move the surrounding fluid, creating thin layers of water that sweep off the plaque.

But previous attempts to create a consumer-grade ultrasonic toothbrush had failed. Ultrasound travels much better in water than in air, and directing the pulses was a challenge. Mourad believed he could do better.

The lab’s engineers inserted a transducer, a machine that turns electric pulses into mechanical pulses, into the head of the toothbrush. Then they built a rubber waveguide to direct those pulses to the edge of the bristles. The prototype was a toothbrush connected to a rack holding about 100 pounds of equipment, including a 150-W amplifier.

Everyone left the room before Mourad tried brushing for the first time. He survived, and a toothbrush was born.

After the physicists had settled on a basic design, the project moved to the School of Dentistry.
‘There have been toothbrushes that tried to use ultrasound,’ said Frank Roberts, an associate professor of periodontics. ‘But they haven’t been very effective. It took people that knew a lot about ultrasound to do it well.’

Dental researchers studied what frequency and intensity of ultrasound would be best to remove plaque and preserve gum health. In the lab, they coated artificial teeth with brightly coloured plaque to compare results using different settings.

Ultreo directs ultrasonic energy toward the bristle tips, which also vibrate but at slower, sonic frequencies. Lab tests showed that adding ultrasound cleared plaque from grooved surfaces better than using a traditional power brush.

‘The addition of the ultrasonic to the power toothbrush was able to remove more plaque from places the bristles didn’t reach,’ Roberts said. ‘I’ve been impressed with it.’

Pierre Mourad, left, a research scientist in the UW’s Applied Physics Laboratory and the Department of Neurological Surgery and Frank Roberts, a researcher in the UW’s School of Dentistry, worked together to invent a toothbrush.

Early research was made possible by three grants from the Washington Technology Center. Clinical trials were funded by the National Institutes of Health through a Small Business Innovation Research grant. Gallagher also raised more than $11 million in start-up money from local investors.

Ultreo is now manufactured by a Redmond-based company of the same name. The company’s scientific director is no stranger to the UW: Chris McInnes received both his doctorate in bioengineering and his bachelor’s in mechanical engineering at the UW.

McInnes’ team worked to shrink the electronics into a toothbrush handle. They further tweaked the product and held clinical trials in the US and Canada. Research showed that adding ultrasound to the power toothbrush removed more plaque than bristle action alone. Ultreo employees also worked to arrange marketing and line up investors, and to design the product.

Linking the company and the scientists was the UW’s Office of TechTransfer, which coordinates the commercialisation of university research.

Ultreo is now shipping to dentists’ offices. Customers can buy the brush online or at participating dental offices for $149. Stores will begin carrying the product in late 2007.

For more information see www.ultreo.com.