A review of studies has shown that nanoparticles can be the best and safest means for whitening teeth.
A review of research conducted by scientists at Sungkyunkwan University in South Korea found that certain types of nanoparticles could be the next leading solution in teeth whitening. Previously, many nanoparticles were not credible due to potential damage when used during invasive whitening procedures. Recently, nanoparticles have been proven to whiten better when used non-invasively and additionally provide antibacterial, anti-inflammatory and remineralizing properties.
Nanoparticles are already widely used in dentistry, including orthopedic dentistry, restorative dentistry, and periodontics. Modern bleaching agents used in clinical practice, such as carbamide peroxide and hydrogen peroxide, can be a potential cause of pathological damage due to the formation of free radicals. One of the studies included in the review proves that nanoparticles are effective not only when added to bleach products, but also when used as bleaching agents. They can perform even better than existing products due to their remineralization and reactive oxygen species release properties, which are also effective in bleaching.
The reactive oxygen species produced are dependent on the nanoparticle: zinc oxide and gold nanoparticles produce hydrogen peroxide, but silver-based nanoparticles produce hydroxyl radicals. The review reported on a study that showed that hydrogen peroxide had an increased whitening effect when gold nanoparticles were used, and another study that demonstrated that the use of gold nanoparticles did not create any biological problems in test animals. However, according to the review authors, more research is needed to test whether these nanoparticles could be toxic.
Another study showed that when combined with long wavelength light, the composition of zinc oxide and biomass carbon provided excellent whitening results, and it showed no apparent toxicity. A similar study showed that when activated with a 405 nm diode laser, a 3.5% hydrogen peroxide solution containing titanium dioxide nanoparticles provided the same level of whitening as a 35% hydrogen peroxide solution.
The review also talks about research into hydroxyapatite, which is known to increase tooth strength by adding apatite to demineralized enamel. One study showed that hydroxyapatite nanoparticles in the form of toothpaste improved tooth color, and another showed that oral care products containing hydroxyapatite nanoparticles were generally safe.