Imagine a future in which a silver diamine fluoride alternative treats cavities and sensitivity and no longer stains teeth, where the lives of dentists become easier and their case acceptance rates move up. Researchers at New York University are currently working on creating a product that can make those visions a reality.
The perfect person to pursue this future is a man who’s had an interest in silver, and other minerals, for a long time. Following a request from the NYU College of Dentistry several years ago, NYU professor of chemistry Marc Walters began to study why silver stains teeth.
Understanding the limitations of silver diamine fluoride
It’s well known in dentistry that when it interacts with tooth decay, silver turns black. This is not a problem for most patients esthetically when it comes to molars, but black teeth when they smile is a different story.
Another mineral used in dentistry—in toothpastes, mouthwashes, cementing agents, and denture adhesives, as well as OTC medications that shorten the duration of colds—caught Walters’ attention: zinc. Walters’ research led him to ask, what if zinc could be used to prevent and treat cavities?
He began to study a zinc phosphate compound to see how it interacts with cavities, and whether it could permeate deep into teeth. To treat pain and hypersensitivity, he knew the compound needed to reach the tooth’s dentin.
Speaking to NYU News, Walters said, “We had to develop a solution to give dentists that will be taken up in these very small openings and go deep enough in the tubules so that the material will be retained.”
Walters applied phosphate followed by zinc to slices of human teeth. While the zinc phosphate successfully permeated the teeth, he knew one step instead of two would be easier and more practical for dentists chairside.
How zinc tetraamoine difluoride works to fight cavities
With SDF as his inspiration, Walters developed a zinc-based molecule called zinc tetraamoine difluoride, which forms a colorless zinc oxide deep inside dentin tubules.1
The agent starts out as a liquid that’s sensitive to concentration and pH. When painted onto a tooth and absorbed, the conditions within dentin tubules prompt a chemical change that quickly turns it into a solid, blocking the tubules and slowly releasing the antimicrobial zinc into the tooth.1
“In one of our studies, two minutes after treatment with our agent, we could see using the electron microscope that the zinc forms long cylinders of mineral that occupy the tubules,” Walters told NYU News. “Blocking the dentin tubules cuts off access to the nerves that are much deeper in dentin. It’s like putting a cork in place that shuts off the lower portion of the tubule from the outside environment, and this happens within a minute or two.”
Walters’ goal is to develop a product that will last months or even years in the teeth to stop hypersensitivity and fight bacteria on an ongoing basis. His samples so far have lasted a few months.
“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 said.
From lab research to commercial product
His work drew the attention of Australian-based company Southern Dental Industries, which purchased the license to the zinc technology. (SDI also currently markets an SDF product that purports to reduce staining.)
Walters now collaborates with NYU professor of molecular pathobiology Deepak Saxena, who has developed oral health products through Periomics Care. The two will work together to develop the zinc products commercially.
Armed with a nearly $300,000 grant from the National Institutes of Health and a Technology Acceleration and Commercialization award from NYU, the researchers will work on their zinc formulation to study the agent’s antimicrobial properties and its ability to block tubules in dentin samples.
One of their goals is a “zone of inhibition,” preventing the growth of decay-causing bacteria in the vicinity of it or even killing bacteria that encounters it.1
Following additional studies of the compound’s formulation, effectiveness, toxicity, and shelf life, the two hope to approach the FDA, along with the company SDI, to gain permission for a clinical trial.
Like any promising product, Walters and Saxena hope to have it on the market soon. While it’s too early to get your patients excited about those nonstained front teeth, dental professionals can keep a close eye out for this zinc product to fight patient sensitivity, avoid scraping and drilling, and overall make their lives easier.
Reference
- Harrison R. Inventing a next-generation cavity fighter. NYU. September 29, 2025. Modified September 29, 2025. https://www.nyu.edu/about/news-publications/news/2025/september/zinc-cavity-treatment.html
