Bentonite clay is a fine powder derived from volcanic ash, recognized for its highly absorbent properties and rich mineral content. It has emerged as a popular additive or replacement for conventional toothpaste in natural dental hygiene routines. The central question is whether this geological material is genuinely safe for regular dental use. The safety of bentonite clay depends entirely on its source and the presence of certain contaminants.
How Bentonite Clay Interacts with Oral Health
The interaction of bentonite clay with the oral environment is driven by its unique negative electrical charge. When mixed with water or saliva, this negative charge allows it to act like a magnet. It attracts and binds to positively charged particles, such as bacteria and toxins, through adsorption, physically removing impurities from the teeth and gums.
Bentonite clay also possesses a naturally alkaline pH, typically ranging between 8.7 and 9.8. This alkalinity helps neutralize the acidic environment created by dietary sugars and bacterial activity. Since tooth enamel begins to erode at a pH of approximately 5.5, maintaining a more alkaline oral environment can help reduce the risk of demineralization and decay.
Assessing Abrasiveness and Heavy Metal Risk
The two most significant safety concerns regarding bentonite clay are heavy metal contamination and the risk of enamel abrasion. As a naturally occurring substance mined from the earth, bentonite clay can contain trace amounts of heavy metals like lead, arsenic, and mercury. The concentration of these elements varies significantly based on the clay’s source, and exposure, even in small amounts, can pose a health risk since the oral mucosa can absorb these substances.
It is paramount to only use clay explicitly labeled as food-grade or pharmaceutical-grade that has undergone third-party testing to verify purity. The U.S. Food and Drug Administration (FDA) has previously warned consumers about specific brands of clay supplements found to contain elevated lead levels. Although manufacturers often claim that any lead present is “bound” and not bioavailable, health experts maintain that no safe level of lead exposure exists.
The risk of abrasion is measured using the Relative Dentin Abrasivity (RDA) scale, which quantifies the erosive effect on tooth structure. A fine-powdered bentonite clay is generally considered a mild abrasive, with some products listing an RDA score around 105. For context, the American Dental Association (ADA) considers products with an RDA of 250 or less safe for a lifetime of use. While the clay is relatively soft, excessive brushing force or frequency can still contribute to enamel wear over time.
Claimed Benefits and Practical Uses in Dental Care
Advocates for bentonite clay in oral care often focus on its perceived ability to “detoxify” the mouth by binding to and removing harmful substances. This claimed detoxifying action is linked to the clay’s powerful adsorption properties, which users believe helps cleanse the mouth of bacterial byproducts and environmental toxins. The clay is also prized for its mild polishing capabilities, helping remove surface stains and debris without the harsh grit found in some conventional whitening products.
A further claim is that the clay contributes to remineralization because it is naturally rich in minerals such as calcium, silica, and magnesium. While these minerals are fundamental building blocks of enamel, the extent to which the clay can effectively transfer them to the tooth structure in a bioavailable form remains a topic of scientific debate.
The clay is used in several ways, most commonly as a primary ingredient in natural toothpastes. Other applications include mixing the powder with water to create a mouth rinse or paste for dry brushing. Some users also apply a thin layer of the clay paste directly to the gums or teeth and leave it on overnight to maximize contact time for its mineral and binding properties.
What Dental Professionals Advise
While dentists acknowledge that bentonite clay acts as an effective mechanical cleaner and can help neutralize oral acidity, they generally advise caution regarding its use as a complete replacement for standard dental care. The primary concern is that bentonite clay products almost universally lack fluoride, which is scientifically proven to be effective at preventing cavities and promoting enamel remineralization. Relying solely on clay-based products removes a highly protective element from a routine.
Dental professionals recommend that bentonite clay be used as a complementary or adjunctive product rather than a standalone solution. They stress the need to consult with a dentist before making a significant switch, especially for individuals with existing dental conditions, sensitive teeth, or a history of enamel erosion. If a person chooses to use the clay, it is advisable to use it for short periods and to alternate with a conventional fluoride-containing toothpaste to ensure comprehensive protection.