Charcoal-Containing Dentifrice Effect on Resin Composite Roughness at 6-Month Simulated Brushing

Charcoal dentifrices are marketed as an alternative to whitening treatments. However, there is a lack of evidence that supports its effect, as well as potential abrasive wear. This study's objective was to evaluate the roughness of a nano-hybrid resin composite during six months of simulated toothbrushing using a charcoal-containing toothpaste, a conventional toothpaste, and a control group using deionised water.

Sixty maxillary and mandibular extracted molars were prepared and restored with a nano-hybrid resin composite, with specimens divided into three groups (n = 20): A charcoal-containing toothpaste, a conventional toothpaste, and a distilled water control. Simulated toothbrushing was accomplished with dentifrice slurry at 200 g-force for 120 cycles per minute for a total of 5,000 cycles, which was equivalent to six months of normal toothbrush use. Specimens were scanned with a laser microscope at baseline and after simulated brushing, with roughness recorded.

No difference (p = 0.6189) was identified between the groups regarding restoration surface roughness before simulated brushing. Significantly greater (p = 0.0323) roughness after brushing was identified with the charcoal toothpaste as compared to the similar (p > 0.9999) conventional toothpaste and distilled water control. Comparison of roughness before and after brushing within each group identified no significant roughness differences within the distilled water (p = 0.5825) and conventional toothpaste (p = 0.5915) groups, while a significant difference (p = 0.0147) was found within the charcoal toothpaste group.

Under the conditions of this study, a charcoal-containing toothpaste caused significantly more resin composite surface roughness as compared to a conventional toothpaste and distilled water control.