Baking soda is not bad for enamel. In fact, it’s one of the least abrasive substances you can use on your teeth, with a hardness lower than both enamel and dentin. Pure baking soda scores just 7 on the Relative Dentin Abrasivity (RDA) scale, where the safe upper limit set by the ADA is 250. That makes it roughly 35 times less abrasive than the harshest toothpastes still considered acceptable.
Why Baking Soda Is Gentler Than Most Toothpastes
Abrasivity in dental products is measured on the RDA scale. Anything below 70 is considered low abrasion. Pure baking soda, at an RDA of 7, barely registers. Toothpastes that contain 50% to 65% baking soda score between 35 and 53, still well within the low-abrasion range. By contrast, toothpastes with no baking soda at all range from 46 all the way up to 245, with many whitening formulas sitting at the higher end.
The reason is simple chemistry: baking soda crystals are softer than tooth enamel and softer than dentin, the layer underneath. When you brush, the baking soda particles break apart on contact rather than scratching the tooth surface. Harder abrasives found in some whitening toothpastes, like hydrated silica, are more effective at scrubbing off deep stains but carry a greater risk of wearing down enamel over time.
How It Actually Helps Protect Enamel
Enamel starts to dissolve when the pH in your mouth drops below about 5.5. Every time you eat or drink something acidic, or when bacteria in plaque produce acid, your mouth temporarily dips into that danger zone. Baking soda is alkaline, and rinsing or brushing with it raises your salivary pH above that critical threshold. A study published in the National Journal of Maxillofacial Surgery found that a baking soda rinse significantly increased salivary pH, pushing it high enough to restrict enamel demineralization and support remineralization, the process by which minerals are redeposited into weakened enamel.
Baking soda also buffers the acids that plaque bacteria produce, increasing saliva’s natural ability to neutralize those acids. So rather than just being “not harmful,” baking soda actively creates conditions that help your enamel repair itself between meals.
Plaque and Gum Benefits
A 12-week randomized clinical trial with 159 participants compared a fluoride toothpaste containing 20% baking soda to a standard fluoride toothpaste. The baking soda group saw significantly greater reductions in plaque, gum inflammation, and bleeding at every checkpoint (4, 8, and 12 weeks). By the end of the study, gum bleeding had dropped 44.2% more in the baking soda group than in the control group. Plaque scores improved by an additional 9.6%, and gum inflammation by 12.6%.
These benefits started fading once participants stopped using the baking soda toothpaste, which suggests the effect comes from regular use rather than a one-time deep clean. The study’s authors concluded that fluoride toothpaste with baking soda offers multiple oral health benefits and can be confidently recommended.
Where People Run Into Trouble
The risks with baking soda come not from the baking soda itself, but from what people mix it with or expect it to do. Adding lemon juice or apple cider vinegar to create a DIY whitening paste is a common suggestion online, and it’s a bad idea. The acidity of those liquids can damage your enamel surface and leave you more vulnerable to cavities, completely undoing the protective alkaline effect baking soda provides.
Brushing with straight baking soda powder also has practical downsides. It doesn’t contain fluoride, the mineral most directly responsible for strengthening enamel and preventing cavities. Used alone as your only dental product, baking soda leaves that gap. The texture is gritty and the taste is salty and unpleasant, which makes it harder to brush for a full two minutes. And while baking soda lifts some surface stains, it’s actually not a strong whitener. It won’t remove deeper, set-in discoloration the way peroxide-based products can.
If you have exposed roots or significant gum recession, the calculus changes slightly. Dentin and cementum (the surfaces exposed when gums pull back) are softer than enamel. Baking soda is still rated as low-abrasion against dentin, but any abrasive, even a mild one, deserves more caution on these vulnerable areas. Gentle brushing pressure matters more than what’s on the brush.
The Best Way to Use It
A toothpaste that combines baking soda with fluoride gives you the benefits of both: the alkaline, plaque-fighting, low-abrasion properties of baking soda alongside fluoride’s proven ability to harden enamel against acid attacks. These formulated products also include flavoring and binding agents that make them easier to use consistently.
If you prefer brushing with plain baking soda, mixing a small amount with water into a paste works fine for occasional use. Just don’t treat it as a complete replacement for fluoride toothpaste. You can also dissolve half a teaspoon in water and use it as a mouth rinse after acidic meals or drinks to quickly raise your mouth’s pH back to a safe level. This is one of the simplest things you can do to protect enamel throughout the day.