Objectives: To study using cobalt-tetraphenylporphyrin/reduced graphene oxide (CoTPP/RGO), a nanocomposite highly catalytic both for oxidizing and for reducing hydrogen peroxide (H2 O2 ), to whiten teeth.
Methods: Dyes (D&C Red 34, Orange No. 4), tea, and betel nuts (Areca catechu) were used to stain the tooth specimens for three days and subsequently bleached using H2 O2 alone, H2 O2 plus CoTPP, or H2 O2 plus CoTPP/RGO for 0.5-70 hours. The process was photographed using an electronic chromometer and a camera. Color change was assessed after each session. The results of bleaching teeth with and without photoirradiation were compared.
Results: CoTPP/RGO increased the tooth-whitening efficacy of H2 O2 for specimens stained with dyes, tea, and betel nuts. Using lamps (photoactivation) (wavelengths: 254 nm and 310 nm) to catalyze the H2 O2 bleaching agent reduced the bleaching treatment time.
Clinical significance: First, the Co/TPP/RGO complex allows improved tooth bleaching and shorter treatment times. Second, because the Co/TPP/RGO complex bleached D&C Red 34 at a similar rate and to a similar degree as tea and other natural agents stain teeth, it is a convenient staining agent for studying many vital aspects of tooth bleaching. (J Esthet Restor Dent 28:321-329, 2016).
© 2016 Wiley Periodicals, Inc.