Optical, Mechanical, and Chemical Impact of Brushing with Activated Charcoal Toothpowder and Toothpaste on Dental Enamel: An In Vitro Evaluation

This in vitro study evaluated the effects of brushing with activated charcoal powder or toothpaste on enamel surface properties, including color change (ΔE), Knoop microhardness (HK), roughness (Ra), and the characteristics of the resulting brushing slurry [pH, fluoride (F^-), and calcium (Ca²⁺) concentration]. A total of 48 enamel samples were stained and divided into 4 groups (<i>n</i> = 12): activated charcoal toothpaste (AC-T), activated charcoal powder (AC-P), hydrogen peroxide-based whitening toothpaste (HP-T), and conventional toothpaste (C-T, positive control). The samples were subjected to a brushing cycling model, and ΔE, HK, Ra and enamel morphology were analyzed at baseline (T0) and after brushing cycle (T1). Additionally, the pH, soluble F^-, and Ca²⁺ concentrations of the slurry were analyzed. Data were analyzed using ANOVA/Tukey and paired <i>t</i>-tests (α = 0.05). After brushing, AC-T and AC-P (<i>p</i> < 0.05) showed a decrease in HK, an increase in Ra, and no ΔE variation was observed between groups (<i>p</i> = 0.163). All products had alkaline slurries (>7), and AC-P had no detectable F^- (<i>p</i> = 0.00) with significantly higher calcium loss (<i>p</i> = 0.015). Fewer enamel topographical changes were observed in C-T. In conclusion, brushing with CA toothpowder and toothpaste does not promote color change, but toothpowder increases surface Ra, decreases enamel HK, lacks F^-, and causes greater Ca²⁺ loss.