Meet Researchers

New research conducted by Hannah Bonelli and her team in the Gottardi Lab marks a hopeful turn in the struggle for a deeper understanding of the temporomandibular joint (aka TMJ or jaw joint). On behalf of The TMJ Association, I interviewed Hannah to raise awareness of her exciting new research.

Hannah found inspiration for her research in an unlikely place: her childhood gymnastics practice. “I was a competitive gymnast and I experienced a lot of injuries, particularly orthopedic ones,” she recalls. Today, Bonelli is a fourth-year PhD student in bioengineering at the University of Pennsylvania, pursuing research to better understand joint tissues – an interest sparked by those childhood injuries. After completing her undergrad education in biomedical engineering at Rowan University, she turned her focus to a small but complex joint most overlook: the TMJ. Bonelli explains, “I’m studying cartilage regeneration in the TMJ, particularly in cases of osteoarthritis.” In other words, she’s researching how to help the body regenerate new cartilage for people whose jaw joints may be worn out or damaged.

Bonelli says she chose the TMJ, in part, because it’s been neglected by researchers. “The orthopedic space is already very congested with thousands of people working on similar topics. The TMJ is a joint that anatomically fits in the orthopedic and dental fields, but it receives very little attention from both groups. And so, this really inspired me to focus on it,” she says. In fact, Bonelli sees herself not just as a laboratory scientist but as an advocate helping to raise awareness. “I kind of want to advocate for the TMJ and for temporomandibular disorders (TMD). I want to bring these issues to light for other people… how prominent they actually are,” she explains. Her excitement about this research is palpable and infectious: she remarks on “how complex this joint is [with] two types of cartilage in the TMJ instead of just one, like other joints.”

In the lab, Bonelli tackles TMJ problems with a classic tissue-engineering approach. “My research is really focusing on two main questions,” she says. “The first is: can we find easily accessible cells that can mimic native TMJ cartilage? The second is: can we combine those cells with a biomaterial scaffold to repair the joint?” To address the cell question, Bonelli looks to unique tissue sources. Bone-marrow stem cells can grow cartilage but harvesting them is painful. As a result, her team turned to simpler biopsies. “We’re currently studying cartilage progenitor cells that we derive from behind the ear — just by a simple biopsy punch,” Bonelli explains. Progenitor cells are specialized early cells that can develop into specific types of cells, playing a crucial role in the development and growth of tissue. In other words, a tiny sample of ear cartilage yields stem-like cells that can make a new cartilage matrix that resembles the native TMJ.

Bonelli’s lab is developing a way to repair damaged jaw cartilage. They start with pig knee cartilage and wash it to remove all the animal cells, leaving behind a natural framework that’s perfect for new cells to grow on. Bonelli explains, “This framework already contains many of the ingredients that help cartilage grow and communicate with cells.” The next step is to add stem cells. Once planted, the stem cells can settle in, multiply, and start turning into cartilage cells, gradually filling in and rebuilding the damaged tissue. “By combining the stem cells with this material, we hope to actually regrow the cartilage in the jaw joint,” she says.

In the long run, Bonelli hopes this engineered construct can be an option between conservative therapy and full joint replacement. “I think my research could really fall in this middle-ground category,” she says. One day, a patient might receive a minimally invasive implant to renew the degrading cartilage, and “maybe… it buys a patient a few years, and they don’t need to get a replacement right away”. In other words, better-regenerating tissue could prolong natural joint function and delay life-altering surgery.

What Can We Do to Help?

I asked Hannah this very question– and her answer was both motivating and inspiring. She urges those affected with TMD to share their stories and spread awareness. “Hearing their stories will always serve as motivation in the back of my mind when days in the lab get tough,” she says. “The research field is growing, and many are becoming more aware of how much we still need to learn about the TMJ,” Bonelli tells us. “Please keep sharing your experiences and needs with us, because it’s so valuable to the progression of science.” In her words, “We’re all in this together, no matter what role you play in the story.” Patient perspectives help researchers identify real-world needs and test practical solutions.

Advocacy groups like The TMJ Association have been key bridges. “The TMJA does a great job bridging that gap, allowing researchers to come in contact with patients,” Bonelli notes. She credits these groups with helping scientists better understand the daily realities of living with TMD. Moving forward, Bonelli believes awareness is the most valuable support anyone can provide to TMD research. “We have to attack advocacy from all angles…patients can bring a perspective that no one else can.”

This article is based on an interview of Hannah Bonelli, PhD Student, at the University of Pennsylvania by Aamena Wahab, a TMD patient and high school student in Illinois.