OBJECTIVE: To quantitatively test the hypothesis that a new paint-on bleaching gel has the potential to lighten tooth color in clinical situations and to evaluate the change of the tooth color six months after the bleaching procedure. METHOD AND MATERIALS: Ten adult subjects requesting tooth bleaching were selected to participate in this randomized clinical trial involving a new in-office bleaching technique using VivaStyle Paint On Plus (Ivoclar Vivadent), originally designed as an over-the-counter bleaching gel. Digital images and CIE Lab spectrophotometric measurements were taken at baseline (I), after the bleaching treatment (PB), and 6 months after bleaching (6M). Differences in Lab values were tested with a repeated measures analysis of variance (ANOVA). Differences in Delta E values were tested with a factorial ANOVA. RESULTS: Significant (P <.05) differences were detected in L, as well as in a and b values, between initial (I) and post-bleaching (PB) and between initial (I) and 6 months post-op (6M). In contrast, there was no significant difference between post-bleaching (PB) and 6 months post-op (6M). CONCLUSION: This new bleaching technique proved to be efficient over a period of 6 months. It could be a less aggressive and more convenient alternative to traditional bleaching techniques.