More people are looking to whiten their teeth and the global teeth whitening market is predicted to grow at a CAGR of more than 6% between now and 2026. Rising consumer awareness of whitening procedures along with the ‘Zoom boom’ over the course of the pandemic, where people are spending an unprecedented amount of time seeing their face in video calls, are thought to have boosted consumer interest. However, whitening runs the risk of tooth sensitivity and gum irritation as well as enamel damage due to the high levels of hydrogen peroxide contained in dentists' bleaching treatments.
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Scientists have developed a near-infrared (NIR) light method to safely whiten teeth with gels that have significantly reduced hydrogen peroxide content. This new technology is predicted to usher in a shift in the cosmetic dentistry industry.
Hydrogen Peroxide in Current Whitening Technology Associated with Adverse Events
The adverse effects of the high levels of hydrogen peroxide in dentists’ bleaching treatments are becoming more apparent. Studies have shown that as many as 78% of patients experience tooth sensitivity following tooth bleaching treatment. Other studies have shown that gum irritation is also a common side effect.
Research has revealed that tooth whitening often damages the tooth’s enamel, leading to dental problems later on. Experts have concluded that the high levels of hydrogen peroxide in dentists’ treatments (up to 40% hydrogen peroxide content) are to blame.
Interestingly, other studies that have investigated the negative impact of tooth whitening have found a potential relationship between exposure to hydrogen peroxide in whitening treatment and oral cancer. Evidence has shown that the substance enhances the carcinogenic effects of potent DNA reactive carcinogens in animal models.
There is clearly a vital need for new, safer whitening treatments that can achieve the same results as traditional dentists’ treatments based on hydrogen peroxide.
Using Nanoparticles and NIR Light to Safely Whiten Teeth
A team of researchers at the West China Hospital of Stomatology, Sichuan University, China, have developed an alternative whitening gel that, with the help of near-infrared (NIR) light, whitens teeth safely without gum irritation.
In a study published in July 2021 in the journal ACS Applied Materials & Interfaces, the team describes how they overcame the limitations of previous approaches to tackle the issue of bleaching gel safety. To date, there have been several attempts to reduce the risk of whitening gels by lowering the content of hydrogen peroxide and augmenting the content of peroxide-derived reactive oxygen species (usually the hydroxyl radical), which is a powerful agent in removing stains from teeth. However, these attempts have failed to result in a final solution positioned to replace traditional, peroxide-heavy, dentist whitening gels.
This study took a different approach. Xingyu Hu, Li Xie, Weidong Tian, and colleagues searched for a catalyst that could utilize low levels of hydrogen peroxide to produce many hydroxyl radicals when exposed to NIR light. The team developed oxygen-deficient titania nanoparticles and, in studies, demonstrated that these nanoparticles could catalyze hydroxyl radical production from hydrogen peroxide. Once exposed to NIR light, this reaction sped up, creating an abundance of hydroxyl radicals. The team observed that the hydroxyl radicals were able to whiten teeth samples safely and effectively in two hours.
Following the success of its initial trials, the team created a gel composed of the oxygen-deficient titania nanoparticles, a carbomer gel, and 12% hydrogen peroxide. They then applied the gel to samples of naturally stained teeth and exposed them to NIR light for an hour. The result showed that the new gel was able to whiten teeth just as effectively as traditional dentist gel containing 40% hydrogen peroxide. As well as relying on significantly less hydrogen peroxide and, therefore, reducing the risk of tooth sensitivity and gum irritation, the new gel was shown to cause less damage to the enamel.
The Future of Teeth Whitening Needs to be Safer
Given the risks associated with currently available whitening technology, it is likely that this innovation that can whiten teeth as effectively as traditional dentists’ methods while reducing the potential negative health effects will cause a shift in the teeth whitening industry. There are already plans to develop the NIR light system for other biomedical applications. It is possible that it will be leveraged to develop new antibacterial materials.
As more research is conducted to examine the effects of exposure to hydrogen peroxide, it is likely that patients will become more aware of the risks and more motivated to choose healthier, safer methods. Additionally, as healthcare professionals, dentists are likely to seek the safest option on the market for treating their patients. Although more research and development are needed, the future is promising for the use of the new whitening system developed by the team at Sichuan University, China.
References and Further Reading
Xingyu Hu, Li Xie, Zhaoyu Xu, Suru Liu, Xinzhi Tan, Ruojing Qian, Ruitao Zhang, Mingyan Jiang, Wenjia Xie, Weidong Tian. (2021) Photothermal-Enhanced Fenton-like Catalytic Activity of Oxygen-Deficient Nanotitania for Efficient and Safe Tooth Whitening. ACS Applied Materials & Interfaces, 13 (30): https://doi.org/10.1021/acsami.1c06774
American Chemical Society. (2021) Whiter teeth, without the burn. [Online]. Science Daily. Available at: https://www.sciencedaily.com/releases/2021/09/210908180637.htm (Accessed on 1 October 2021).
Hu, X., Xie, L., Xu, Z., Liu, S., Tan, X., Qian, R., Zhang, R., Jiang, M., Xie, W. and Tian, W., (2021) Photothermal-Enhanced Fenton-like Catalytic Activity of Oxygen-Deficient Nanotitania for Efficient and Safe Tooth Whitening. ACS Applied Materials & Interfaces, 13(30), pp.35315-35327. https://pubs.acs.org/doi/10.1021/acsami.1c06774
Munro, i., Williams, g., Heymann, h. and Kroes, r., (2006) Use of Hydrogen Peroxide-Based Tooth Whitening Products and its Relationship to Oral Cancer. Journal of Esthetic and Restorative Dentistry, 18(3), pp.119-125. https://pubmed.ncbi.nlm.nih.gov/16831183/
Susman, E., (2004) Tooth Whiteners Scrutinized for Oral Cancer Risk. Oncology Times, 26(19), p.84. https://journals.lww.com/oncology-times/fulltext/2004/10100/tooth_whiteners_scrutinized_for_oral_cancer_risk.31.aspx
Tredwin, C., Naik, S., Lewis, N. and Scully, C., (2006) Hydrogen peroxide tooth-whitening (bleaching) products: Review of adverse effects and safety issues. British Dental Journal, 200(7), pp.371-376. https://www.nature.com/articles/4813423