Applying technology from aerospace engineering to the human jaw

Ritesh Bhattacharjee was working as a dental oncologist in India when he met Raktim Bhattacharya, PhD, a Texas A&M associate professor in aerospace, electrical and computer engineering at the Dwight Look College of Engineering. In the course of their conversation, they discussed lockjaw—the inability to open the mouth widely—that resulted from radiation therapy for head and neck cancer.

“It was a weird coincidence,” Bhattacharjee said. “I had just been talking to my colleagues about the devastating effects that lockjaw (also called trismus) can have.” When someone has trismus, nutrition can suffer (because the person can’t open their mouth enough to eat) and oral hygiene becomes very difficult. Existing devices are cumbersome and painful to use and are only somewhat effective.

Bhattacharya was intrigued and mentioned that it was possible he and one of his graduate students, Michael Young, might be able to create a robotic device to help. “The novelty here is using system identification concepts traditionally used in control system design for aircrafts, now being applied to the human jaw,” Bhattacharjee said.

Young and Bhattacharjee were working together on their idea online before Bhattacharjee joined the master’s of public health program (MPH) at the Texas A&M Health Science Center School of Public Health. “I applied other places,” Bhattacharjee said, “but I chose Texas A&M because of this project.” They’ve been getting positive feedback for the need for such a device from health care providers from around the world. “Doctors from Nigeria were excited because they have patients with tetanus who develop trismus,” Bhattacharjee said, pointing out that patients beyond those with cancer could benefit.

The pair knew they would need someone with business sense if they were going to bring a device to market, so they got together with Steven Arose, a JD/MBA student from Temple University that Young had met at an internship. They also asked Lynne Opperman, PhD, a professor of biomedical science at the Texas A&M University Baylor College of Dentistry, for help. Opperman had some experience bringing a medical device to market, so she agreed to participate as the team’s industry mentor. “Ritesh knew that there was an unmet need for patients with trismus,” Opperman said. “It was quite obvious in my discussions with both him and Michael that they were very focused about what they wanted to do.”

The team joined the I-Corps program, a National Science Foundation course that teaches researchers how to reduce commercialization risks, in the summer of 2015 to work through the next steps and determine if there was really was a large enough unmet need to justify the device development. “I think I learned as much if not more than Michael and Ritesh did from the I-Corps program,” Opperman said. “Even if you think that your invention is the coolest thing out there, they teach you how to understand what issues there might be to getting it into the marketplace.”

After doing six weeks of intensive interviews with health care providers, insurance companies and patients, the team moved away from the idea that the device would be used to treat trismus, but decided something that allows you to look at function of the “chewing apparatus as a whole would be useful,” Opperman said. “They’re creating essentially the same device, but they’re thinking about what they’re measuring in very different ways.” Instead of looking narrowly at trismus, the team has starting thinking more broadly about how the jaw functions.

“Everyone’s jaw is unique,” Bhattacharjee said, and physicians could program the device to adjust for jaw abnormalities and provide targeted therapies. The device could also measure improvement so both the patient and the doctor could actually see progress, which could then improve willingness to use the device.

There is also a need for greater basic research into trismus itself. “What I like about the device is that it is pointing out the deficiencies in the research that is currently out there,” Opperman said, “and pointing to a whole new area of research: what are these patients suffering from?”

It’s not clear what happens in radiation therapy, whether it damages the nerve or the muscle itself. “If the nerve is permanently damaged,” Opperman said, “you can exercise the muscle as much as you’d like, but it won’t do any good.” The next step would be to try to tease this out, possibly in collaboration with a muscle biologist at the College of Medicine. “People can’t exactly diagnose why trismus happens,” Bhattacharjee said. “We need to find the root cause and piece together exactly what’s going on.”

“Michael and Ritesh are remarkable,” Opperman said. “They represent a rare partnership between engineering and health. I think they have a really cool device, and I really hope we can get to the point where we’re actually building prototypes.”