A study from a team of researchers led by Penn Dental Medicine’s Dr Hyun Michel Koo in collaboration with Dr David Cormode of Penn’s Perelman School of Medicine and School of Engineering and Applied Science has unveiled an unexpected synergy in the battle against dental caries.
Their research revealed that combining stannous fluoride, SnF2, – the fluoride routinely used in dental care products – with ferumoxytol, Fer, an off-the-shelf iron oxide nanoparticle formulation, could point to a potent solution against dental caries. Their findings were published in Nature Communications.
According to a press release from Penn Dental Medicine, while fluoride-based treatments have long been the gold standard in dentistry for preventing tooth decay, this singular approach does not sufficiently control biofilm — the main culprit behind dental caries — and prevent enamel demineralisation at the same time. This dual dilemma becomes particularly pronounced in high-risk populations where the onset of the disease can be both rapid and severe.
“Traditional treatments often come short in managing the complex biofilm environment in the mouth,” said Dr Koo, senior co-author on the study. “Our combined treatment not only amplifies the effectiveness of each agent, but does so with a lower dosage, hinting at a potentially revolutionary method for caries prevention in high-risk individuals.”
Their findings include the ability of Fer to stabilise SnF2, the heightened catalytic activity of Fer when combined with SnF2, and the formation of a protective Fe/Sn/F-rich film on tooth enamel, which can serve as a shield against further demineralization. Moreover, the researched reported that this combined therapy does not disrupt the ecological balance of the oral microbiota and has no adverse side effects on the surrounding host tissues.
“What excites us most is the multi-faceted approach to caries prevention. It is not just about inhibiting bacterial growth or protecting the enamel; it’s a holistic method that targets both the biological and physicochemical aspects of dental caries,” said Dr Cormode, senior co-author of the paper.
The researchers also note that, beyond this protective and proactive measure, a secondary benefit surfaced. Many children with severe tooth decay also suffer from iron deficiency anaemia. Using Fer might address the dental and anaemia concerns simultaneously.
Reflecting on the next steps, Dr Koo said: “While we are happy with these initial findings, we aim to dig deeper in understanding the intricate mechanisms of action while advancing Fer-SnF2 combination treatment to clinical trials.”
Another significant advantage of this combined treatment is the promise of a quick transition to clinical applications. Since Fer is an off-the-shelf iron oxide nanoparticle formulation, using it topically at a fraction of its approved systemic dosage could fast-track its path to practical applications and commercialisation without the long, arduous journey of new drug approvals.
Looking ahead, the researchers added that further research is required into the exact mechanisms of interaction between SnF2 and Fer, the reactive oxygen species generation process, and the formation and efficacy of the protective enamel film.
“There is potential here not just in dental care but in exploring how this combination can be targeted against other biofilms,” Dr Cormode said.
Other authors are Yue Huang, Nil Kanatha Pandey, Shrey Shah, and Jessica C Hsu of Penn’s Perelman School of Medicine; Yuan Liu, Aurea Simon-Soro, Zhi Ren, Zhenting Xiaang, Dongyeop Kim, Tatsuro Ito, Min Jun Oh, and Yong Li of Penn’s School of Dental Medicine; Paul J Smeets, Sarah Boyer, Xingchen Zhao, and Derk Joester of Northwestern University; and Domenick T Zero of Indiana University.
The work was supported by the National Institute of Health (grants R01-DE025848 and TL1TR001423 and awards S10OD026871 and R90DE031532) and the National Science Foundation (awards ECCS-2025633 and DMR-1720139).
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