Tearing open gingival cells when toothbrushing may help keep gingivae healthy, say researchers in the August issue of Journal of Dental Research.
Researchers at the Medical College of Georgia (MCG) in Augusta injected a fluorescent dye that can only get into torn cells in rats’ blood streams. They then brushed the rats’ teeth, gums and tongues with a modified electric toothbrush.
"We saw lots of bright cells," said study co-author Dr. Katsuya Miyake, professor, School of Medicine, MCG, and co-director of the MCG Cell Imaging Core Facility.
They found that even using the toothbrush with gentle force could tear holes in the epithelial cells that line the gingivae and tongue, causing a momentary rupture. This tearing let calcium, which is abundant in saliva, move into the cells, which triggered internal membranes to move up and patch the hole. In addition, in the seconds that the repair required, growth factors, which promote growth of collagen, new cells and blood vessels, leaked out of injured cells.
Researchers also found that cell injury turned on the expression of the c-fos gene, an early-response gene that often is activated under stress and that may be the first step in a response such as cell division or growth.
They concluded that toothbrushing disrupts cell plasma membrane barriers in the oral cavity and activates gene expression events that may lead to local adaptive changes in tissue architecture that are beneficial to gingival health.
The study was supported, in part, by a grant from the National Aeronautics and Space Administration.
