This article is based on a recent paper published in ACS Applied Materials & Interfaces, “Fast Cross-Linked Hydrogel as a Green Light-Activated Photocatalyst for Localized Biofilm Disruption and Brush-Free Tooth Whitening.”
It’s not just a cliché that the first thing people notice about you is your smile: a 2010 survey found nearly half of us choose a great smile as a person’s most attractive feature.1 Furthermore, aspects of oral hygiene such as bad breath (89%) and yellow teeth (79%) took the lead for major turn-offs.1 Is there a chemistry solution for this very human problem?
Globally, around 3.5 billion people suffer from oral diseases such as tooth decay and gum disease,2 many of which can be prevented through good oral hygiene. But traditional toothpastes remove only surface stains, and bleaching treatments can harm enamel. New research published in ACS Applied Materials & Interfaces reports on a novel hydrogel treatment that can break apart cavity-forming biofilms and whiten teeth without damage.
Current whitening treatments combine hydrogen peroxide gels with blue light, producing a chemical reaction that removes stains but also generates reactive oxygen species that can break down enamel and potentially damage exposed skin and eyes. Researchers at Nanchang University in China wanted to find a material that could instead be activated by a safer green light to both whiten teeth and prevent cavities.
The research team designed an injectable sodium alginate hydrogel membrane doped with bismuth oxychloride and cubic cuprous oxide nanoparticles to simultaneously achieve local tooth whitening and biofilm removal through a photodynamic dental therapy process.3 This was tested ex vivo on teeth stained with coffee, tea, blueberry juice, and soy sauce. Following treatment with the hydrogel and green light, teeth got brighter over time with no damage to the enamel. Additionally, the treatment killed 94% of bacteria in biofilms.
To demonstrate efficacy in vivo, the team used the new method on mice whose mouths were inoculated with cavity-forming bacteria, and they found that the new method prevented both moderate and deep cavities forming on tooth surfaces. The researchers report that their safe, brush-free treatment both effectively prevents cavities and whitens teeth, demonstrating a promising strategy for oral health care in the future.3
Watch the video around this research created by the ACS Science Communications team:
- Philips Sonicare Survey. Oral Care Love Affair: Americans Open up About Their Oral Health. 6 December 2010.
- World Health Organization. Oral Health Fact Sheet. 15 March 2022.
- Li Q, et al. Fast Cross-Linked Hydrogel as a Green Light-Activated Photocatalyst for Localized Biofilm Disruption and Brush-Free Tooth Whitening. ACS Appl Mater Interfaces 2022;14(25):28427–28438.
Further reading on this topic
A safe and effective way to whiten teeth
American Chemical Society. Press Release. 18 July 2018
Photothermal-Enhanced Fenton-like Catalytic Activity of Oxygen-Deficient Nanotitania for Efficient and Safe Tooth Whitening
Xingyu Hu, Li Xie, Zhaoyu Xu, Suru Liu, Xinzhi Tan, Ruojing Qian, Ruitao Zhang, Mingyan Jiang, Wenjia Xie, and Weidong Tian