Charcoal-based dentifrices and powders: analyses of product labels, Instagram engagement, and altmetrics.

This study identified charcoal-based dentifrices and abrasive powders sold in Brazil and analyzed their label information. The products were searched in four online shopping platforms. The same products were searched on Instagram and their engagement metrics were investigated. Furthermore, a literature review of international publications assessing charcoal dentifrices and powders was conducted, and altmetrics were collected (Altmetric and PlumX). Thirty-six products were found with prices between $0.4-22 USD. Most frequent words in product description were sodium, stain, whitening, oil, xylitol, and coconut. Only 3 products contained fluoride. Bactericidal, antiviral, antifungal, and anti-inflammatory activities were indicated, in addition to non-scientific claims such as calming teeth or increasing oral immunity. In total, 72% of products had Instagram profiles, which generally showed low engagement rates (81%) and medium audience quality scores (65%). Twenty-two articles were found in the literature, from which 21 were in vitro studies. The single clinical study was sponsored by a charcoal product and had no control group. In total, 23% of studies showed positive results and 55% reported negative results for the charcoal products, which included no whitening ability, increased roughness, surface alterations, and lower demineralization prevention ability. Altmetric scores for the included articles varied from 0 to 55, with 40.9% of studies mentioned online. In conclusion, charcoal-based products are using marketing strategies on Instagram but their current engagement with the public is not high. Consumers are being exposed to charcoal products whose potential risks to health are still unknown.