Stem Cell Technique Could Help Kids Avoid Root Canal

THURSDAY, Dec. 21 (HealthDay News) -- The promise of stem cells may someday help kids say goodbye to the dreaded root canal, scientists report.

A new, less-invasive treatment leaves the soft inner pulp intact, allowing the young tooth's stem cells to continue tooth formation.

"Removing infected tissue by root canal is invasive, and, by doing that, we stop the tooth's continuous maturation process and leave behind a child with a thin eggshell of a tooth that is weak and susceptible to fracture," explained researcher Dr. George T.-J. Huang, an endodontist (root canal specialist) and an associate professor with the University of Maryland's College of Dental Surgery.

In the December 2006 issue of theJournal of Endodontics, his team reviewed four cases of preteen tooth decay treated by Taiwanese dentists who cleaned infected tooth tissue but didnotremove it -- leaving pulp stem cells to remain in place. These stem cells went on to help the teeth recover, regenerate, and mature into strong healthy teeth.

The researchers stressed that the stem cells in question are adult stem cells (rather than controversial embryonic stem cells) that all children and adults possess. And the cleaning procedure that they used to replace traditional root canal is based on the application of a bleaching substance, rather than any introduction of externally derived stem cells.

"By leaving the tissue and just removing the infection, we observed in these cases that not only are the gums healed and the children's teeth free from infection and abscesses but, most importantly, there is a stem-cell aided completion of the root formation and tooth maturation over time," Huang said.

His team focused on a common form of tooth decay called periodontitis. The condition stems from deposits of bacterial plaque below the gum line that can lead to tissue and bone decay, gum recession, exposure of tooth roots, and eventually tooth loss.

Endodontists typically offer patients root canal to treat this condition. Root canal involves the use of dental instruments to remove the infected soft pulp tissue -- commonly referred to as "nerve" tissue -- located in the center of the tooth. The hollowed-out pulp chamber that once housed the extracted tissue is then filled and sealed to prevent re-infection or the spread of bacteria to other areas.

According to dental experts, the excised nerve tissue is not critical to normal oral function once adult teeth have matured, so removal of degenerated matter does not induce long-term problems.

However, nerve/pulp tissue is vital to the healthy development of teeth in children under the age of 16. The adult tooth-maturation process takes approximately three years to complete from the time a tooth first appears.

That means that in younger patients, root canal can stop this process and boost risks for dental complications, fractures, and even facial disfigurement.

But Huang's team knew that the pulp in maturing teeth is much richer in blood supply than that seen in adults. It also has a greater ability to regenerate itself compared to the pulp inside adult teeth. That's because stem cells inside children's teeth have the capacity to generate into the material that forms "dentin" -- the tooth's primary connective tissue.