Yang Chai and his fellow researchers at the Herman Ostrow School of Dentistry, USC have understood how genes for the roots of teeth are turned on and off.
This is a key step to regrowing human teeth.
To find out how the human body changes over time, scientists are increasingly looking to gain deeper knowledge into the field of epigenetics, the study of changes in organisms caused by modifications in gene expression rather than the change of the genetic code itself. This scientific endeavor also extends to teeth.
Yang Chai, associate dean of research at the Herman Ostrow School of Dentistry of USC, reported in a recent article how he and his colleagues discovered that epigenetic regulation can control tooth root patterning and development.
“This is an aspect that doesn’t involve change in the DNA sequence, but it’s basically through the control where you make the genes available or unavailable for transcription, which can determine the pattern,”
Ezh2 is a protein which helps facial bones to develop, but it was not clear how exactly it affects the development of tooth rot, the authors stated.
The team decided to look at what would happen when Ezh2 is not present in the molar teeth of mice that are still developing.
They discovered that Ezh2 and Arid1a, another protein, need to be in balance to pinpoint the pattern of tooth rot as well as the proper integration of roots within the jawbones.
The goal is to someday regrow teeth by firstly regenerating the roots.
Mr. Chai says that dietary changes and environment affect the way our bodies regulate genes, which in itself is evident when looking at the difference between the formation of our teeth and the teeth of ancient humans.
“I feel excited about this because, through human evolution, there have been changes in our diet and environment that can influence our epigenome — the ways our genes are regulated – and you can clearly see a difference between the root formation of our dentition versus Neanderthals,” Chai said
The molars of Neanderthals have longer root trunks than those seen in modern-day humans and show a late splitting of the roots, which could be due to the effect of dietary habits and exercise on the proteins that turn genes on and off.
Regulator balance also has a hand in wellness and disease. Research has shown that in different types of cancer the balance of two opposing epigenetic regulators is crucially important.
Disabling one regulator can lead to the development of cancer, Chai said, but modulating its opposing regulator can prevent it.
“These epigenetic regulators, which are not changing the DNA sequences, are important in themselves, but their level of their activity is also important,” he said. “Basically, you can’t have too much or too little — if the balance is off track, then you get developmental problems or disease,” Chai stated.
The end goal of Chai and his team’s research on the regulation of tooth development is the regrowing of teeth – however, generating an entire tooth is extremely challenging because it takes a long time to build a tooth from development to eruption, Chai expanded. So, the aim is to find the most effective ways to regenerate a molar root and put a crown on top.
“It would be the best of both worlds: a natural integration of the root with the jawbone with the periodontal ligament in place, and a reduction in the amount of time we need by using just a crown to restore function,” he continued.
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