"Most of orthodontics has traditionally dealt with physics, the biomechanics of applying a force against a tooth to move it," said study investigator Timothy Wheeler, D.M.D., Ph.D., a professor and chairman of orthodontics at UF's College of Dentistry. "Ours is the first study to use a naturally occurring hormone, recombinant human relaxin, to biochemically augment tooth movement and retention."
Relaxin is best known as the hormone that helps women's pelvic ligaments stretch in preparation for giving birth. It does this by softening collagen and elastin in the tissues, loosening strong, cord-like fibers until they have the consistency of limp spaghetti noodles.
That ability prompted researchers to consider relaxin a possible way to accelerate tooth movement and prevent relapse, a condition where the tooth migrates back to its original position after braces are removed.
"You can imagine normal collagen and elastin fibers to be like rubber bands that attach to the tooth to hold it in place," said Wheeler. "Those tissue fibers resist the force of the orthodontic treatment applied to move the tooth, and, when that force is removed, say when the braces are taken off, the elasticity of the tissues springs the tooth back into position."
UF researchers will evaluate whether injecting relaxin into the gums will loosen the collagen and elastin fibers and reorganize them so teeth can move more freely into orthodontic alignment. Once the teeth have been moved, researchers will administer another injection of relaxin under the premise that it will further soften gum tissue fibers, preventing them from pulling teeth back into their original position.