NYU College of Dentistry researchers are developing a next-generation treatment for tooth decay that could offer a non-invasive alternative to traditional drilling and filling. The new approach replaces silver with zinc to eliminate the black staining associated with silver diamine fluoride, while still targeting bacteria and alleviating pain.
Silver diamine fluoride is an inexpensive and easily administered liquid treatment that is already approved by the U.S. Food and Drug Administration for tooth sensitivity. Research at NYU has shown that its antimicrobial properties also make it effective in preventing and arresting early-stage cavities. The treatment has proven useful in settings with limited access to dental care, such as schools and rural areas, and for patients with disabilities.
However, the silver component in silver diamine fluoride turns decayed areas of teeth black, which poses a cosmetic drawback, especially for visible teeth.
“Once your teeth are treated with silver diamine fluoride, that stain is permanent, which is a barrier for many people wanting to use the product,” explains Marc Walters, professor of chemistry at NYU.
Several years ago, researchers at NYU College of Dentistry approached Walters to investigate the staining mechanism and explore ways to prevent it. Walters, who has studied silver and other elements used in medicine, turned his attention to zinc — a mineral known for its antimicrobial properties and widespread use in oral care products.
“What if another mineral could be used that was also colorless and antimicrobial but didn’t turn teeth black?” Walters asked. This question led to the exploration of zinc, which is found in everyday dental products such as toothpaste, mouthwash, and denture adhesives.
According to NYU College of Dentistry, Walters’ lab tests showed that zinc oxide remained in tooth samples for at least one to two months. The goal is to develop a long-lasting agent that can relieve tooth sensitivity and inhibit bacterial growth.
“Not only do you have the analgesic result of having tubules blocked, but you also have a very low solubility agent that can slowly release the zinc into the tubule to prevent the growth of Streptococcus mutans and other bacteria,” Walters says.
The technology soon gained interest from Southern Dental Industries (SDI), an Australian manufacturer of dental materials including silver diamine fluoride. SDI acquired the license for the zinc formulation and is collaborating with NYU to advance its development.
Walters also began working with Deepak Saxena, professor of molecular pathobiology and director of research innovation and entrepreneurship at NYU College of Dentistry. Saxena co-founded Periomics Care, a startup focused on oral health innovations.
“As soon as I met Marc and I saw his enthusiasm, I decided that we should work together and try to make this as a commercial product,” Saxena says.
Their collaboration brought together expertise in chemistry, microbiology, and dentistry. According to NYU College of Dentistry, the pair received a Technology Acceleration and Commercialization award from the university and, in August, secured nearly $300,000 in funding from the National Institutes of Health through its Small Business Technology Transfer program.
The NIH grant will support further feasibility studies of the zinc formulation by Walters’ team, focusing on its ability to block dentin tubules. Simultaneously, Saxena’s group at Periomics Care will study the compound’s antimicrobial effects, including whether it can create a “zone of inhibition” to prevent or kill decay-causing bacteria.
“The mouth is full of bacteria. A compound needs to have good antimicrobial activity, which can occur from ionic imbalance, the properties of the zinc, or by the fluoride,” Saxena says. “If a compound does not stain, has good antimicrobial activity, plus it blocks the tubules, then it should be successful in stopping tooth decay and be aesthetically accepted.”
According to NYU College of Dentistry, upcoming phases of research will evaluate the zinc agent’s formulation, efficacy, toxicity, and shelf life. If these studies are successful, the researchers — along with SDI — plan to seek FDA approval for clinical trials.
Because zinc phosphate is already used in dental adhesives and approved in various forms by the FDA, NYU College of Dentistry notes that this prior usage could accelerate development timelines compared to treatments using untested compounds.
“We know that there's a need — and a market — for a product that stops tooth decay that is effective, cheap, easy to use, and non-staining, given the rise in global numbers of untreated cavities,” Saxena says.
According to NYU College of Dentistry, the new treatment could reduce the need for drilling, shorten dental chair time for children, and offer a more aesthetic option for older adults with root exposure and associated sensitivity. If proven safe and effective, it may eventually become available directly to consumers.
For Walters and Saxena, the goal remains clear: to reduce the global burden of untreated cavities and provide a tooth-friendly solution without the visual downsides of silver.
