New toothpaste stops gum disease without killing good bacteria: Study

Periodontitis is a common condition that can affect much more than just oral health. Scientists at Fraunhofer have discovered a compound that specifically blocks the bacteria responsible for this disease while leaving the rest of the oral microbiome intact. This innovation has since been developed into a range of oral care products by the spin-off company PerioTrap.

The human mouth contains more than 700 types of bacteria, but only a small number are linked to periodontitis. These harmful microbes collect in dental plaque, especially along the gum line, where they can trigger inflammation (gingivitis). If left untreated, this inflammation can progress into chronic periodontitis, leading to gum recession and tooth loss.

The risks extend beyond the mouth. When disease-causing bacteria enter the bloodstream, they may play a role in serious conditions such as diabetes, rheumatic disease, arthritis, cardiovascular disease, chronic inflammatory bowel disease, and even Alzheimer's disease.

Why Conventional Treatments Fall Short

Traditional oral care products like alcohol-based mouthwashes and chlorhexidine solutions kill harmful bacteria, but they also wipe out beneficial microbes. After treatment, the oral microbiome has to rebuild itself from scratch. In this process, harmful bacteria such as Porphyromonas gingivalis often regain dominance quickly because they thrive in inflamed gum tissue. Beneficial bacteria grow more slowly, which can lead to an imbalance known as dysbiosis and allow the disease to return.

A New Way to Block Harmful Bacteria

Researchers at the Fraunhofer Institute for Cell Therapy and Immunology IZI in Halle identified a substance that targets harmful pathogens without affecting the rest of the microbial community. This compound, called guanidinoethylbenzylamino imidazopyridine acetate, works by preventing the growth of bacteria like Porphyromonas gingivalis rather than killing them outright.

Stephan Schilling, Head of the Fraunhofer IZI branch Molecular Drug Biochemistry and Therapy Development, explains: "Rather than simply killing gingivitis pathogens, it inhibits their growth. They are unable to exert their toxic effects, so beneficial bacteria can occupy niches that would otherwise be inaccessible to them. In this way, the substance works in harmony with healthy bacteria to gently rebuild and stabilize the microbial balance in the mouth," says Schilling.

From Research Project to Toothpaste

The underlying technology was first developed through an EU-funded research project involving international partners. In 2018, Periotrap Pharmaceuticals GmbH was established in Halle to turn this discovery into practical oral care solutions. Working closely with Fraunhofer IZI and the Fraunhofer Institute for Microstructure of Materials and Systems IMWS, the team created a toothpaste designed to support the oral microbiome.

"The product is designed to prevent periodontitis. Like conventional toothpaste, it also contains abrasives and fluoride to prevent tooth decay," explains Mirko Buchholz, one of the company's founders.

Overcoming Development Challenges

Transforming the compound into a usable ingredient required extensive testing. The final product needed to block harmful bacteria effectively while remaining safe for everyday use. It could not be toxic, enter the bloodstream, or cause discoloration of teeth.

To achieve this, Fraunhofer IZI researchers carried out biochemical and structural studies to better understand how the substance works and to fine-tune the formulation. "This allows us to gain a better understanding of how the substances work and determine the optimum composition of the toothpaste's active ingredients," Schilling explains.

Testing Toothpaste Safety and Effectiveness

Fraunhofer IMWS contributed by evaluating how different formulations interact with teeth and gums. Using advanced tools such as scanning electron microscopy and chemical analysis, researchers examined compatibility and performance in detail.

As Andreas Kiesow, Group Manager Characterization of Medical and Cosmetic Care Products, explains: "Scanning electron microscopy, chemical characterization and quantitative measurements enable us to draw detailed conclusions about a substance's compatibility and function. To put it simply: We ultimately find out whether the toothpaste works or not."

Quality Standards and Future Products

All testing followed Good Laboratory Practice (GLP) standards, ensuring that results meet strict national and international requirements. "Compliance with GLP guidelines was a key element of the project. We didn't just develop a good toothpaste with a new ingredient: we developed a high-quality oral care product of medical-grade standard," says Schilling.

Work on the technology is continuing. In addition to toothpaste, researchers and the PerioTrap team have developed a gel used after professional dental cleanings to block harmful bacteria, support a healthy microbiome, and maintain gum health.

More products are in development, including a mouthwash and other oral care solutions. There is also potential for use in veterinary care, since gum disease in dogs and cats has similar underlying causes.