Efficacy of Different Over-the-Counter Bleaching Systems on Human Teeth

Objective: Evaluate the efficacy of four different over-the-counter bleaching systems. Methods: Sixty extracted anterior human teeth were cleaned and polished. The teeth had a shade range of A2 to C3 on a value-oriented shade guide (Vita Lumin, Germany) and were mounted in arch-like fashion, in dental stone (WhipMix, Kentucky). Two groups of 6 teeth were randomly assigned to each bleaching system tested, which were: hydrogen peroxide (dSolve, Natural White – 7days) [NWd], carbamide peroxide 22% (Professional White, Rembrandt/Oral-B – 7days) [RPW], hydrogen peroxide 5% (2 Hour White, Rembrandt/Oral-B – 2hours) [R2W], hydrogen peroxide 8% (Whitening Strips, Rembrandt/Oral-B – 7days) [RWS] and carbamide peroxide 10% (Night White, Discus Dental – 7days) [C] the control group. The application and duration of the OTC bleaching products were following the manufacturer's recommendations. Teeth were kept inside a container at 100% humidity during the treatment. Tooth color was measured at baseline (T0), after one treatment (T1), after a second treatment (T2) and one week post-treatment (T3) by two examiners. Shade values were converted to a numerical value from 1 (B1) to 16 (C4). The effect of duration for each treatment groups was analyzed using one-way repeated measures ANOVA (p£0.05). Within-subjects contrasts were then performed to identify significant differences with baseline shade value. Results: For all groups, significant tooth lightening was obtained after the completion of one treatment (T1). However, at T1, a statistically significant difference (p=0.02) was found between the product [C] and [NWd]. The [C] product had lightened the teeth by 4 shades compared to 2 shades for the [NWd]. At T2, groups [C] and [RWS] were statistically different from groups [NWd] and [R2W]. Conclusion: Because of the method of application and time duration, not all the OTC bleaching products produce the same tooth lightening effect.