What Growing Incisors Reveal About Genetic Disease

The Dynamic Nature of Teeth and Their Medical Significance

Teeth are often viewed as static structures, but recent advancements in interdisciplinary research are revealing their dynamic and informative nature. A groundbreaking collaboration between engineers and clinicians is uncovering the potential of teeth as a valuable resource for understanding rare craniofacial disorders that develop during childhood.

This study, published in ACS Applied Materials & Interfaces, highlights how teeth, as biological materials, can provide critical insights into developmental processes. Kyle Vining, Assistant Professor in Materials Science and Engineering and Preventive and Restorative Science at Penn Dental Medicine, leads this interdisciplinary team. The group includes Yuchen (Tracy) Jiang, a former master's student in MSE; Kei Katsura, a pediatric dentist and KL2 postdoctoral research scholar at Children's Hospital of Philadelphia (CHOP); and Elizabeth Bhoj, Assistant Professor of Pediatrics in Penn Medicine and the Division of Human Genetics at CHOP.

Through their innovative methodology, the team has combined materials science, mineralogy, and human genetics to map out the properties of enamel and dentin development. This approach has the potential to offer new insights into identifying and treating both rare craniofacial diseases in children and common dental cavities.

Understanding Tooth Mineralization

The project centers on a fundamental question: How do teeth mineralize? Despite its importance, scientists still lack a complete understanding of this process. "This is an exciting step in determining how teeth develop and harden," says Katsura. "Tooth mineralization is such an intricate process with many hidden secrets we get to uncover."

To answer this question, researchers turned to an unexpected tool from geology: the nanoindenter, typically used to test the hardness of rocks. By adapting this technology, the team analyzed tiny sections of tooth enamel, though the task was far from straightforward.

"Sample preparation was one of the most challenging parts," says Jiang, the lead author on the paper. "Tooth is such a hard and heterogeneous material. It's layered, shifting, and biological. Embedding it properly for testing took a lot of troubleshooting."

Once the samples were prepared, the team used advanced techniques such as nanoindentation, scanning electron microscopy, energy dispersive spectroscopy (EDS), and Raman spectroscopy to measure various properties of tooth enamel, including elasticity, stiffness, and mineral content.

Linking Tooth Development to Disease

While Jiang and Vining focused on the physical properties of teeth, Katsura brought in the biological perspective by examining mouse models of Mendelian genetic disorders that mimic human craniofacial syndromes. Bhoj contributed her expertise on these rare diseases, guiding the project toward practical clinical applications.

"These disorders are hard to treat in part because little attention is paid to the oral cavity, so we don't always know how dental and oral conditions relate to the systemic issues these children face," says Katsura. "But we're showing that materials science can help us find part of the answer."

One of the major challenges is that teeth start developing in utero, making early study difficult. However, by analyzing structural changes during development and linking them with function, researchers hope to trace back to understand what went wrong during the process.

"We're excited to be able to integrate tools of materials science to learn about the properties of tooth development," says Vining. "Our work lays the foundation for further studies that could lead to diagnostic tools or even new materials for fillings that prevent decay."

Future Implications and Collaborative Growth

This research is already influencing the team’s future work on genetic craniofacial diseases in mice. In the long term, the researchers envision their tools being used in dental clinics to screen for enamel defects, assess treatment outcomes, or even predict disease risk.

Beyond scientific breakthroughs, the project is also reshaping how researchers approach collaboration. Jiang, who trained as a materials scientist, reflects on her experience working outside her comfort zone.

"You don't need to have everything figured out before working on a project. I've learned that growth happens along the way and that learning from collaborators is one of the most valuable parts of scientific research," she says.

"The most exciting discoveries come from different people bringing different strengths."