Dental scientists have discovered the bacterium that causes gum disease, according to a new study.
University of Michigan researchers found that it delivers a one-two punch.
The bacterium, NI1060, causes usually protective proteins in the mouth to destroy more bone as well as triggering gum disease.
Scientists and oral health care providers have known for years that bacteria cause gum disease - also known as periodontitis.
But until researchers discovered NI1060, they hadn't identified the specific bacterium.
They found that it also sparks a generally protective protein in the oral cavity, called Nod1, to turn treacherous and actually trigger bone-destroying cells.
Nod1 usually fights harmful bacteria in the body.
Yizu Jiao, a postdoctoral fellow at the U-M Health System, and lead author of the study, called identifying the mechanise responsible for gum disease a "major discovery".
Jiao and Noahiro Inohara, research associate professor at the U-M Health System, collaborated with William Giannobile, professor of dentistry, and Julie Marchesan, formerly of Giannobile's lab.
Giannobile said: "The findings from this study underscore the connection between beneficial and harmful bacteria that normally reside in the oral cavity, how a harmful bacterium causes the disease, and how an at-risk patient might respond to such bacteria."
The new research appears in the recent issue of the journal Cell Host and Microbe .
Copyright Press Association 2013