Evaluating a Cobalt‐Tetraphenylporphyrin Complex, Functionalized with a Reduced Graphene Oxide Nanocomposite, for Improved Tooth Whitening

Objectives To study using cobalt‐tetraphenylporphyrin/reduced graphene oxide (CoTPP/RGO), a nanocomposite highly catalytic both for oxidizing and for reducing hydrogen peroxide (H 2 O 2 ), 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 H 2 O 2 alone, H 2 O 2 plus CoTPP, or H 2 O 2 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 H 2 O 2 for specimens stained with dyes, tea, and betel nuts. Using lamps (photoactivation) (wavelengths: 254 nm and 310 nm) to catalyze the H 2 O 2 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)