SEOUL, South Korea: A review by researchers from Sungkyunkwan University in South Korea has suggested that certain types of nanoparticles could be the next leading solution in tooth whitening treatment. Previously untrusted because of the potential to cause damage if used for invasive whitening procedures, many nanoparticles have been proved to improve whitening when used in non-invasive ways and additionally provide antibacterial, anti-inflammatory and remineralisation properties.
Nanoparticles are already in wide use in dentistry, including prosthetic dentistry, restorative dentistry and periodontics. Current whitening agents used clinically, such as carbamide peroxide and hydrogen peroxide, can be a potential cause of pathological damage due to the generation of free radicals. The review suggests that, not only are nanoparticles useful when added for abrasion to whitening products, but also used as whitening agents they may function even better than existing products because of their ability to promote remineralisation and their release of reactive oxygen species useful for whitening as well.
The reactive oxygen species produced depends on the nanoparticle: zinc oxide and gold nanoparticles produce hydrogen peroxide, but silver-based nanoparticles produce hydroxyl radicals. The review reported on research that found that hydrogen peroxide had an increased whitening effect when gold nanoparticles were used and on another study that demonstrated that the gold nanoparticle use created no biological problems in the animals tested. However, more research needs to be done to verify whether these nanoparticles could potentially pose a toxicity risk, according to the review authors.
In combination with long-wavelength light, another study reported on suggested that a composite of zinc oxide and biomass carbon provided superior whitening results, and it found no obvious toxicity. A similar study showed that, when activated by a 405 nm diode laser, a 3.5% hydrogen peroxide solution containing titanium dioxide nanoparticles provided an equal level of whitening to that of a 35% hydrogen peroxide solution.
The team also reported on research on hydroxyapatite, which is known to add strength to teeth by adding apatite to demineralised enamel. One study determined that the hydroxyapatite nanoparticles improved tooth colour in toothpaste form, and another indicated that oral care products containing hydroxyapatite nanoparticles are generally safe.
The study, titled, “Nanoparticles as next-generation tooth-whitening agents: Progress and perspectives”, was published on 15 June 2022 in ACS Nano, ahead of inclusion in an issue.