DNA Dental Work Rebuilds Tooth Support

DNA Dental Work Rebuilds Tooth Support
Technique could eliminate need for bone grafts and transplants
2/2/2005
Betterhumans Staff
Betterhumans.com
A gene therapy that spurs the growth of tooth-supporting bone could make dental work far more pleasant.
The technique could eliminate the need to use bone grafts or transplants in replacing a lost tooth.
In people with a large mouth wound, replacing a tooth requires the creation of bone structure to anchor it in place. This is currently done with a bone graft from the chin or jaw that leaves a second wound or with donated bone from a tissue bank.
Researchers at the University of Michigan in Ann Arbor are developing a different approach: Introducing a growth factor protein into mouth wounds to spur bone generation around dental implants.
Wound repair
William Giannobile of the university's school of dentistry has led a team of researchers in delivering a gene encoding for the protein, bone morphogenetic protein-7 (BMP-7), to large bone defects in rats.
Animals that received the treatment produced nearly 50% more supporting bone around dental implants than those receiving conventional treatment.
"This study represents a proof-of-concept investigation," says Giannobile. "We are encouraged about the promise of this treatment."
Spurring growth
BMP-7 is part of a protein family that regulates cartilage and bone formation and has recently been found present in tooth development and periodontal repair.
For their study, the researchers mixed BMP-7 genes with an inactivated virus in a gel-like carrier and injected it into wounds.
The viruses entered cells and injected their cargo.
Gene expression producing BMP-7 proteins peaked after a week, say the researchers, acted quickly to spur bone growth and disappeared within 28 days.
Giannobile says this is ideal because the team wasn't aiming to make permanent genetic changes.
Human trials
While more work is needed before the approach can be tested in humans, Giannobile optimistically wants to see initial human trials within four to seven years.
Next steps may include finding nonviral approaches to gene delivery.
Another possibility is developing a way of conducting gene therapy outside the body and then transferring cells back into a patient, although this would require an extra surgical procedure.