A Spanish team studied the side effects of typical oxidation-based teeth whitening treatments compared to a new treatment developed by the authors based on reduction.

For better teeth whitening results, higher concentrations of oxidizing agents and longer application times are required, but this may increase side effects such as hypersensitivity and pulp damage, demineralization teeth and gum irritation. Moreover, the need to apply these products for hours is not very comfortable for the user.

Typical tooth whitening treatments are based on the oxidizing power of hydrogen peroxide, which breaks the double bonds of the coloring molecules on the surface of the teeth, rendering them unable to absorb light. In this way, the molecule becomes transparent, resulting in a bright, white smile.

Researchers from the Universitat Autònoma de Barcelona (UAB) in collaboration with Synchrotron ALBA used bovine incisors as an in vitro model to study the side effects of bleaching treatments. They compared typical bleaching treatments (based on carbamide peroxide oxidation) to a new treatment developed and patented by the authors by reduction via metabisulphite, which also renders the coloring molecules colorless. However, metabisulphite exhibits a faster whitening effect, allowing lower concentrations and shorter application times to be used.

Results published in Dental materials showed that the whitening effect of the new treatment was greatly improved in terms of required application time, efficacy and safety, making it a promising candidate for developing new whitening treatments.

In addition, they found that the use of oxidative or reductive treatments promotes different mineral modifications. This was known thanks to the chemical imaging carried out on the MIRAS beamline at ALBA.