In a patient with a sizeable mouth wound, replacing a tooth takes more than simply implanting a new one---the patient also needs the bone structure to anchor the new tooth in place. Such reconstructive surgery today involves either taking a bone graft from the patient's chin or jaw, which leaves a second wound needing to heal, or using donated bone from a tissue bank, which yields unpredictable results.

William Giannobile, professor of periodontics, prevention and geriatrics, led a team at the U-M School of Dentistry that delivered the gene encoding for bone morphogenetic protein-7 (BMP-7) to large bone defects in rats in an attempt to turn on the body's own bone growth mechanisms. The study showed that animals that got the BMP-7 treatment produced nearly 50 percent more supporting bone around dental implants than those receiving the conventional treatment.

"This study represents a proof-of-concept investigation. We are encouraged about the promise of this treatment," said Giannobile, also an associate professor of biomedical engineering and director of the Michigan Center for Oral Health Research.

More work will need to be done before the approach can be tested in humans, Giannobile added. He said he optimistically would like to see initial trials begin in humans in four to seven years.

BMP-7 is part of a family of proteins that regulates cartilage and bone formation. Recent studies have shown that BMPs are present in tooth development and periodontal repair.

This study mixed BMP-7 genes with an inactivated virus in a gel-like carrier and injected it into wounds. Giannobile said using a virus, with the harmful effects turned off, harnesses the
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Contact: Colleen Newvine
cnewvine@umich.edu
734-647-4411
University of Michigan
1-Feb-2005