Dentistry pops up in places you’d least expect it. Just recently, I attended the Color Factory pop-up exhibit in San Francisco, a “gallery” where each room celebrates a different color. A lady in the black and white room was serving charcoal-filtered lemonade. She explained to me that charcoal is used in many things these days, including teeth-whitening products, which immediately piqued my interest. Once the connection between charcoal and teeth had been established in my mind, I seemed to hear about the relationship multiple times across many places. There was even a small talk about the two at the ASDA Annual Session conference this past February. I decided to consult a variety of resources to investigate the relationship between charcoal and its use in whitening teeth.

Charcoal has an activated form under high temperatures, which contains a negative electric charge. This activated form of charcoal is key in the theory of it being able to whiten teeth. The activated charcoal is highly porous, which can bind to often-positively charged toxins in the teeth through microscopic pores. After binding to these microtoxins in theory, the charcoal then gets brushed off with a toothbrush and water, removing stain-causing materials from the tooth’s surface. This, in theory, not only removes stains, but also harmful agents, which could potentially reduce caries in the process of creating a brighter tooth. Some countries have even produced large quantities of toothbrushes with charcoal bristles (Ramachandra, et al., 2014).

A lot of these theories rely on activated charcoal’s previous known properties for use in toxin removal, as sometimes seen as treatment for drug overdoses. In terms of scientific studies, the results are mixed. The majority of studies are inconclusive on any positive or negative effects. A few small-scale studies are in support of this theory and have claimed to see caries reduction from use of activated charcoal. Others found harmful outcomes, namely in regard to abrasion from the activated charcoal causing enamel erosion. In terms of abrasivity, different toothpastes are assigned a Relative Dentin Abrasivity (RDA) value, where a value higher than 200 is considered abrasive and harmful to teeth (Noir, 2017). Most activated charcoal toothpastes score between 70 and 90, although this varies by brand and product. Therefore, the type of activated charcoal dentifrice used can be seen as a potential outlying variable in these studies.

The most recent study done on activated charcoal’s effects on teeth was a literature review in September 2017 in the Journal of the American Dental Association. JADA compiled multiple studies from previous years, and ultimately found no conclusive results from caries reduction or enamel abrasion (Brooks et al., 2017). Therefore, more studies must be conducted before any benefits or harmful effects can be confirmed.

Ultimately, people should be careful when using any dental products utilizing activated charcoal, as the exact short- and long-term potential effects are unknown until further research is conducted.

~ Michael Mears, University of California, Davis ’17 

References:
Nature.com: Oral health: Charcoal brushes.
JADA: Charcoal and charcoal-based dentifrices
Charbonnair.com: Can active charcoal powder damage teeth enamel?