Researchers of the Universitat Autònoma de Barcelona (UAB) in collaboration with the ALBA Synchrotron have studied the side effects of typical tooth whitening treatments based on oxidation compared to a new treatment developed by the authors through reduction. Results, published in Dental Materials, showed the whitening effect of the novel treatment to be highly improved in terms of application time needed, efficiency and safety, which makes it a promising candidate to develop novel whitening treatments. Experiments at the MIRAS beamline of ALBA helped to determine the chemical mineral modifications in the dental enamel.