The human mouth is full of wonders. It’s home to hundreds of species of bacteria, fungi, viruses and protozoa, which work in delicate harmony to maintain our oral health. Sometimes, though, this complex system — known as the oral microbiome — can fall out of balance. Anaerobic bacteria build up on the tongue and in the little pockets between our teeth and gums. There, they break down organic matter and spew out a foul odor. This, the current theory goes, is what causes many chronic cases of bad breath, or halitosis.
To rebalance the oral microbiome and cure chronic halitosis, researchers at the University of Washington are embarking on a first-of-its-kind experiment. These clinical trials transplant bacteria and other minuscule critters from healthy donors into patients with halitosis. If successful, the healthy microbiota will crowd out the bad and patients’ bad breath will improve.
“We know the oral microbiome can get out of whack. The question is, can you rebalance it? That is the hypothesis we’re proposing,” said Alvin Wee, a UW professor of restorative dentistry and co-lead of the project.
The experimental procedures build off recent breakthroughs in fecal microbiota transplants, commonly known as stool transplants, which have become a go-to treatment for gastrointestinal infections and bacterial imbalances.
The research team has so far completed four transplants, with preliminary evaluations underway. They’re seeking pairs of participants — a patient with chronic halitosis and a donor, ideally an intimate partner, family member or trusted friend — to undergo these relatively simple procedures.
To start, researchers complete a full periodontal exam of the donor to ensure their microbiome is healthy. Then they collect bacteria from the donor and suspend it in a small volume of saline. At the same time, recipients undergo a deep cleaning to remove the harmful bacteria and disrupt the biofilm — the thin, sticky layer of microorganisms that lines surfaces in the mouth. Recipients rinse with the donor solution, and researchers inject a concentrated version into the gumline. Ninety days after the transplant, participants self-report whether their breath has improved.
“What we’re trying to do is severely disrupt the original bacteria, and then we bring in the new guys to take hold and establish a new biofilm,” said co-lead Alex Pozhitkov, a research scientist and affiliate faculty member in the UW School of Dentistry. “If we bring enough of the new bacteria and they outcompete the ones that we disrupted, the healthy ones will take over. It’s a numbers game.”
This research was funded by the Dean and Margaret Spencer Clinical Research Fund. Co-investigators include professor of clinical practice Diane Daubert and professor Daniel Chan, both of the UW School of Dentistry. For more information, to reach the researchers or to inquire about participating, contact Pozhitkov at pozhit@uw.edu or Wee at awe@uw.edu.