7 July 2005

Teeth On The Move

by Kate Melville

The dreaded trip to the orthodontist could soon become far less painful for those who need to have teeth moved about. In the first study of its kind, University of Florida (UF) researchers are testing the power of a natural human hormone called relaxin to biochemically move teeth faster and less painfully during orthodontic treatment. Relaxin is a hormone that helps women's pelvic ligaments stretch in preparation for giving birth. That ability prompted researchers to consider relaxin as 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.

"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, 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."

Most of the problems associated with orthodontic treatments have to do with the body's natural elastins resisting manipulation. "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."

This painful and inconvenient problem is what led researchers to consider injecting relaxin into the gums to 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. Wheeler said researchers hope to determine whether the treatment could eliminate the need for patients to wear retainers to hold teeth in place after braces are removed. "Right now, retention is the biggest problem we have in orthodontics," Wheeler said. "I want to get completely away from retainers, which for most patients right now are a lifetime commitment."

The drug was given the green light last April from the Food and Drug Administration. The UF study will establish safety and proof of principle on 40 people before a series of multi-center studies.

Unfortunately, relaxin does nothing to numb the pain in the hip pocket that often lingers after orthodontic treatment.

Source: Media release - University of Florida