
Patients ask us about various topics all the time. As their doctor, and an expert, we really want to feel comfortable answering those questions with accurate information. I’ve received several questions from dentists about the use of baking soda (sodium bicarbonate) as an alternative to commercial toothpaste, and especially regarding its claimed ability to whiten teeth. Obviously, these dentists have been asked these same questions by their patients, who’ve seen wild claims all across the internet. As a consequence, I took a look at the claims on the Internet about baking soda. To say I was blown away with the inaccuracy (including some articles written by dentists) is an understatement. So I thought the following information may be of help to you. Search the Internet regarding brushing your teeth or whitening your teeth with baking soda, and among other ridiculous things, you’ll routinely see the claim that baking soda is VERY abrasive to use on your teeth – so if you use it, don’t use it every day. Absolutely wrong! These statements are not only wrong, but they’re pretty much as wrong as you can get. Baking soda (the stuff in the box in the super market) is, by far, the lowest abrasiveness of anything you would ever brush your teeth with. Here’s the problem – non-scientists writing articles based on assumption, and not proven fact. And once ONE person writes something, others quote him or her. Then when you have several people saying that same [false] thing, people state it and believe it as fact. After all, if enough people say the same thing, it must be fact, right? Wrong! And the most disconcerting thing for me is that some of these articles have been written by dentists, who also simply read what others said on the internet, so they too assumed that baking soda is excessively abrasive. Why do so many people “assume” baking soda is extremely abrasive? It’s because the particles are large and have sharp edges, so it “feels” gritty when you touch it. Below on the left you see a microscopic photo of baking soda particles. Notice how they have edges and corners. Below on the right you see silica particles, which would be the most common abrasive in toothpastes. Notice how rounded and smooth the silica particles are. But also realize that the baking soda particles are much, much larger than the silica particles. Baking soda particles can be as much as 15 times larger than silica particles in toothpaste. |

So what’s the difference? Silica particles are much, much harder than baking soda particles. When you forcefully rub two hard objects against each other, the harder object will have almost zero damage, and the softer object will be greatly scratched and damaged. For example, a diamond is a hardness of 10 on the Mohs Hardness Scale, and glass is rated at 5. So diamond is two times harder than glass. Well, that’s not exactly true because the Mohs Hardness Scale is an ordinal scale, so there is no data on how much difference there is between the numbers. But you already know if a diamond is firmly rubbed against glass, it will scratch the glass, but the diamond will not be damaged. Mohs Hardness of materials (remember this is an ordinal scale, so there is no mathematical formula of consistent distance between each number):Tooth enamel = 5Tooth dentin/root = 3Baking soda = 2.5Hydrated silica in toothpaste = 5-7Baking soda “feels” much more gritty than regular toothpaste (which usually has hydrated silica as the abrasive) because the particles are larger, and the edges are rough. Whereas silica particles are more round, smooth, and many times smaller. So baking soda “feels” more abrasive – but it’s not. The fact is that Baking Soda, being much softer than tooth enamel, and very slightly softer than even tooth dentin, will not create much damage (abrasion) to the tooth. The American Dental Association has published their RDA (Relative Dentin Abrasivity) to measure the abrasiveness of various toothpastes. The RDA abrasiveness categories are:Low 4-70 (plain water is 4. Baking soda is 7.)Medium 70-100High 100-150Harmful 150-250 The FDA limits abrasiveness to a maximum of RDA 200. Get this…the RDA of Arm & Hammer baking soda is only 7. Whereas the most typical tooth paste will be in the 70-100 range with many far above that. THAT is how gentle baking soda is, as far as abrasion to your teeth. Of course, keep in mind that commercial toothpastes that claim to be baking soda toothpastes also contain other abrasives. So using baking soda in the commercial toothpaste may be thought of as somewhat of a marketing gimmick to get you to buy the toothpaste. This means you can brush your teeth with more paste and for a longer time if you’re using straight baking soda mixed to a paste with only water. That alone will help physically remove more bacteria and more stain. Why? Stain will typically be softer than baking soda, so, though baking soda will not cause much abrasion of your teeth, it’s still hard enough to scrape off many types of stain from your teeth. The main problem with using straight baking soda/water paste? No fluoride. And of course, baking soda is harder than gingival tissue, so brushing longer may cause gingival abrasion and recession over time. So there’s good and bad here. |
Baking Soda to Whiten Your Teeth |
So now let’s talk about the ridiculous claim that brushing with baking soda will whiten your teeth. This is simply wrong…period! There has never been any scientific study that even hints that baking soda may whiten your teeth. Of course, if you’re talking about using baking soda to simply brush with to remove stain from the surface of your teeth, then yes, baking soda will do that, just like any other toothpaste in the world. But does it have any other chemical or other means of any kind that will “whiten” your teeth? Absolutely, positively not! |
But now….the REALLY DANGEROUS information. |
Of course, all dentists know how acid ravages tooth structure. When you do an Internet search of whitening your teeth with baking soda, often you’ll find instructions to add lemon juice, apple cider vinegar or some other acidic ingredient along with the baking soda. And you already know what a bad idea THAT is! |
But wait…it gets even worse… |
You’re mixing baking soda, which is at least somewhat abrasive, and acid together. Gee, doesn’t that remind you of microabrasion products that we dentists use on teeth to remove the surface of tooth structure – such as removing surface dark or white spots? Possibly the most popular microabrasion product out there is Ultradent’s Opalustre. It’s an excellent product. It has hydrochloric acid mixed with silicon carbide microparticles. The acid SOFTENS the surface tooth structure, which the abrasive particles quickly remove. Mixing baking soda and lemon juice or apple cider vinegar will do exactly the same thing, but on a less aggressive scale. When thinking about patients doing this continually over time, this is the perfect way to wear away their tooth structure. And the thing that really kills me is that most using this technique falsely believe it’s a very safe and “natural” way to whiten teeth. Yeah, sure! “Natural” like a rattlesnake bite! But it’s one of the worst, most ineffective, and especially permanently damaging things you can do to your teeth. |
Dr. Rod KurthyFounder/CEOEvolve Dental Technologies, Inc. Thanks Dr. Kurthy for a great informative article… ~ Dr. Greg Friedman |