Researchers gain new insight into mineralization of tooth enamel
CHICAGO, U.S.: Hydroxyapatite is an important component of hard tissue. Tooth enamel, for example, has the highest concentration of the mineral. Since dysfunctional hydroxyapatite mineralization may lead to medical problems such as dental caries, understanding the mineralization pathway of hydroxyapatite has been of great interest. Researchers from the University of Illinois at Chicago have now reported new findings on the nucleation and growth of hydroxyapatite that they hope will help in developing new medical treatments for healing bone and dental cavities.
“Until now these pathways, particularly at the early stages when molecules are first starting to organize into a structure, have not been understood clearly,” said co-author Prof. Reza Shahbazian-Yassar, from the Department of Mechanical and Industrial Engineering at the university, in a university press release.
In their experiments, the researchers captured high-resolution, real-time images of the mineralization process in an artificial saliva model, using a microdevice that made it possible to use electron microscopy with a liquid model. This method allowed them to monitor chemical reactions in the model on the smallest scale.
They observed that both direct and indirect formations of hydroxyapatite crystals can be achieved by local variations in energetic pathways for nucleation and growth. “The control over the dissolution of amorphous calcium phosphate affects the assembly of hydroxyapatite crystals into larger aggregates,” said Shahbazian-Yassar. The simultaneous coexistence of these pathways explains why different groups have reported seemingly different or opposite results, he continued.
In addition, the researchers now understand how hydroxyapatite materials nucleate and grow on amorphous calcium phosphate substrate. Shahbazian-Yassar commented on the study results: “By better understanding these pathways, scientists are one step closer to engineering ways to better treat dental diseases and bone injuries—like those from traumatic injuries—or prevent medical conditions that can develop when normal mineralization processes in the body go awry.”
According to Shahbazian-Yassar, the researchers next intend to investigate how molecular modifiers can affect the process of biomineralization, which is crucial in developing effective drugs.
The study, titled “Revealing nanoscale mineralization pathways of hydroxyapatite using in situ liquid cell transmission electron microscopy,” was published in the Nov. 18, 2020, issue of Science Advances.