Do Activated-Charcoal Toothbrushes Whiten Teeth? A Randomised Comparative In Vivo Study Using Spectrophotometric Colour Analysis

Objective: This study compared the effect on tooth colour (colour change and whiteness) of two commercially available charcoal-coated toothbrushes with that of a conventional toothbrush. Materials and Methods: In this randomised, assessor-blinded, parallel-group study, forty-seven adults were randomised to Colgate 360° Charcoal (C360C, n = 15), Curasept Black Luxury (CBL, n = 17), or a conventional control brush (n = 15). All participants used a whitening toothpaste for 20 days, followed by a non-whitening toothpaste for 20 days. Tooth colour was measured spectrophotometrically at baseline and after 20 and 40 days, and the CIE76 (ΔE*ab) and CIEDE2000 (ΔE00) colour differences and the Whiteness Index for Dentistry (WID) were calculated. Satisfaction (visual analogue scale, VAS), psychosocial impact (PIDAQ), and adverse effects were also recorded. Results: The colour change from baseline to day 40 (ΔE00, primary outcome) did not differ between the charcoal brushes and the control (mean difference, −0.29; 95% CI, −1.13 to 0.55 for C360C and −0.14; 95% CI, −1.07 to 0.79 for CBL). Small differences in L*, a*, and b* during the first phase were no longer statistically significant at day 40, and WID did not increase in any group. Satisfaction increased in all groups, including the control (p < 0.001), and self-reported adverse effects did not differ significantly between groups. Conclusions: No evidence was found that charcoal-coated toothbrushes whiten teeth more than a conventional toothbrush; given the small sample, equivalence cannot be inferred. The increase in satisfaction in all groups may reflect expectations and study participation rather than the type of toothbrush.