Impact of brushing with charcoal on tooth color and enamel loss: An in vitro study

To evaluate the whitening efficacy of charcoal powder compared to a whitening toothpaste and the surface loss using scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM).

60 human extracted teeth were randomly assigned to two groups: Treatment (T, charcoal group: Premium Nature) and Control (C, whitening toothpaste group: Colgate Optic White). Teeth in the treatment group were brushed with a charcoal paste. Teeth shade was evaluated before and after the intervention. Lightness was assessed using both VITA classical shade guide and VITA Easyshade V. Changes within and between the group were evaluated by the paired-sample t-test and independent sample t-test. Surface roughness (Ra) of samples was performed using SEM, and to assess surface loss a CLSM was used.

At baseline, there were no significant differences in teeth lightness, chroma, or hue between both the charcoal and the whitening toothpaste groups (P> 0.05). After 21 days of brushing, teeth brushed with the whitening toothpaste were significantly lighter (VITA Easyshade mean score: 78.34, SD: 8.397; VITA classical A1-D4 shade mean: 8.90, SD: 4.475) than the charcoal group (VITA Easyshade mean: 69.70, SD: 6.364; VITA classical A1-D4 shade mean: 11.77; SD: 3.421) (P< 0.001). In addition, there was a significant reduction in lightness (i.e., increase in darkness) within the charcoal group after the intervention (P< 0.001). There was no significant difference in chroma and hue between the charcoal and the whitening toothpaste groups (P> 0.05). There was no significant tooth loss nor roughness change (P= 0.867) for both groups when compared with natural tooth structure. Brushing teeth with the charcoal paste tested for 21 days had no effect on tooth lightness, chroma, or hue. Charcoal powder had no significant effect on tooth surface roughness.

The Premium Nature charcoal toothpaste tested had no tooth whitening effect.