To compare two home-based over-the-counter (OTC) bleaching tray products with similar hydrogen peroxide (HP) concentrations with respect to tooth lightening efficacy and potential to induce negative side effects in tobacco- and non-tobacco users as well as degree of satisfaction with product handling. The HP concentrations were near the regulation limit for bleaching products of 6% set by the European Union in 2011.

The use of optical radiation in the so-called light-assisted tooth bleaching procedures has been suggested to enhance the oxidizing effect of the bleaching agent, hydrogen peroxide. Documentation is scarce on the potential adverse effects of bleaching products and on optical exposure risks to eyes and skin.