Tooth Regeneration May Replace Drill-and-Fill:
While regrowing your uncle’s toothless grin from scratch is still a decade away, the ability to use some of the body’s own building materials for oral repair would be a boon to dentists, who have been fixing cavities with metal fillings since the 1840s. Enamel and dentin are remarkably strong and long-lasting, and they can repair themselves. But as scientists are continuing to find out, dentin in particular is a remarkably complex structure.The outer covering of teeth is enamel. The body makes it by growing tiny mineral crystals in a highly regular crystal lattice. Underneath that ceramic-like covering, dentin is like hard clay reinforced by fibers of collagen, similar to the way adobe bricks contain clay reinforced by straw fibers.
“The tooth is a beautiful structure,” said Van Thompson, dentistry professor and chairman of New York University’s Department of Biomaterials and Biomimetics.
But teeth, because they are made from minerals, are susceptible to what is essentially erosion. Acids, like those produced by bacteria or Coca-Cola, demineralize the enamel of the teeth. Usually the body is constantly repairing small amounts of damage, Marshall said. But when the body’s defenses become overwhelmed, bacteria break through into the dentin below, and you get tooth decay, commonly called a cavity.
The acid produced by the bacteria eats into the minerals in the dentin, turning it mushy and useless. Normal dentin is twice as stiff as pinewood, but damaged dentin is more like rubber, which makes it pretty hard to chew with.
Marshall’s newest work, which has been accepted for publication in the Journal of Structural Biology, focuses on regrowing dentin in damaged teeth with the help of a calcium-containing solution of ions (electrically charged particles).
By putting a layer of the solution on individual test teeth, Marshall has already been able to remineralize some parts of the teeth. The challenge is to get the crystals to regrow throughout the dentin.