The interplay between toothbrush stiffness and charcoal-containing dentifrice on the development of enamel topography changes

Abstract Background This study aimed to investigate the in vitro effect of a charcoal-containing dentifrice with different toothbrush stiffness on enamel. Methods Four main groups were applied: distilled water, conventional fluoridated toothpaste (Colgate® Total® 12 Clean Mint Toothpaste), charcoal toothpaste (Colgate® Total® Charcoal Toothpaste) and whitening toothpaste (Colgate Total® Advanced Whitening Toothpaste). Three subgroups for each toothpaste were further included according to the toothbrush bristles’ stiffness (soft, medium, and hard). Enamel specimens were subjected to 1,250 and 2,500 cycles of brushing using toothbrushing simulation machine. The average surface roughness change (ΔRa) in nanometer (nm) was measured to estimate the changes following the brushing simulation model. Two-way ANOVA and Tukey tests analyzed the data. Results The type of toothpaste and the bristles’ stiffness were determinant factors in increasing the ΔRa value (P =