This in vitro study aimed to assess the effects of the inorganic elements in charcoal-based dentifrices on the bovine enamel in terms of surface morphology and composition. Enamel surfaces (n = 10/group) obtained from bovine incisors were brushed with the conventional toothpaste Oral-B Complete (OBC; negative control), the whitening toothpaste Colgate Luminous White Expert (LWE; positive control), and the activated charcoal-based dentifrices Colgate Natural Extracts Purifying (CNE), Curaprox Black Is White (CBW), and Oral-B 3D White Mineral Clean (OBW). Enamel samples were analyzed using microenergy-dispersive X-ray fluorescence spectrometry (μ-EDXRF), surface roughness (Ra), contact angle (CA), and scanning electron microscopy (SEM). FT-Raman and Fourier-Transform Infrared (FTIR) spectroscopy and SEM were used to analyze the particulate fractions of the dentifrices. Enamel Ra varied between 0.029 (0.006) and 0.037 (0.006) and demonstrated no significant between-group difference. The CA values ranged from 90.59 (13.16) in the OBC to 102.6 (13.32) in the CBW, with no significance. μ-EDXRF revealed significant mineral loss with the OBC and CNE, while SEM confirmed deeper abrasion patterns linked to larger heterogeneous particles. FT-Raman and FTIR spectroscopy validated the compositional profiles, identifying silica, carbonates, hydrogen peroxide, and charcoal that explain the observed changes. Overall, charcoal-based dentifrice CNE produced the greatest mineral depletion and heterogeneity, whereas LWE, CBW, and OBW maintained more intermediate or protective effects.
Alvarenga et al. (Mon,) studied this question.