The Fugue

So I went to the dentist the other day and he recommended I stop using that awful baking soda toothpaste. Oh how he wishes it wasn't even on the market. It's the worst thing to happen to dental health since dulce de leche!

Whatever. Whenever I heard superlative statements, even when calmly uttered by specialists and authority figures, warning bells go off. On the other hand, the possibility that I might stop suffering from sensitive teeth is enough to warrant some research.

His claim against baking soda is that it's too abrasive. When I came home and started googling, I found that the Arm & Hammer people are saying that baking soda is less abrasive than the silica abrasives most toothpastes use. Somebody's wrong. Both are trying to sell me stuff (the dentist wanted to give me prescription Prevident toothpaste, which of course they sell). Neither can be trusted (ok, maybe the dentist can be more trusted to have my best interest at heart, but in my experience health care professionals for all their heart can't always be trusted to get all the facts straight. Ask them for supporting evidence. If they can't back it up with science, they might be mistaken!). I need facts.

After a bit of googling, I found an interesting report by some students (undergradutes, by the look of it) at the University of Waterloo. They rigged up a dremel to brush teeth for the equivalent of 82 years and compared straight baking soda, Arm & Hammer toothpaste, and Topol (a fairly abrasive smoker's toothpaste). They found Arm & Hammer didn't noticeably abrade the teeth, Topol did mildly, and baking soda did severely. Unfortunately, there wasn't a comparison between a baking soda toothpaste and a regular (silica) toothpaste.

Finally I found some information about the Relative Dentin Abrasivity (RDA) index. Armed with this new keyword I started finding more substantial information on the abrasiveness of various toothpastes. This article at Satyen.com has an excellent description of the methods and a nice table of results for many toothpastes, including sources. In addition, it is reported (complete with hyperbole) that toothpaste companies will usually give you the RDA values of their toothpastes if you call and ask (but apparently Crest doesn't).

So looking at the Sayten.com chart, which is corroborated by various bits and pieces scattered across the web, baking soda toothpaste is neither automatically better nor worse than other brands. They are all in it together. One thing that you do notice is that whitening formulas have higher abrasion than non-whitening, and sensitive formulas tend to lower abrasion, but there are toothpastes that aren't labeled sensitive that are just as low or lower.

Most interestingly, baking soda alone has a very low RDA of 7. This doesn't jive with the report by the students at the University of Waterloo, but could be explained by a difference in methods. One possible explanation is that baking soda in toothpaste (and presumably that used in the RDA tests) is ground finer than the stuff in the box and/or has more liquid added which allows it to dissolve into finer particles.

Based on the lower RDA numbers that Arm & Hammer toothpastes tend to get when they're not whitening, it would seem that baking soda is indeed possibly a gentler cleaning agent than silica, but other factors come into play.

To be fair to my dentist, he did mention that whitening toothpastes were bad for sensitive teeth, and I have indeed been using a whitening variety. He also disparaged tartar control as useless and perhaps bad for sensitive teeth. I didn't research that in depth.

It should also be mentioned that RDA isn't the whole story. There's also Pellicle Cleaning Ratio (PCR). You want a high PCR and low RDA, i.e. more cleaning power with less abrasion. Obviously it's a balancing act. Water alone has a nice low RDA of 4, but obviously water alone doesn't clean as well as a toothpaste. And we're not talking just get the dulce de leche off, we're talking about removing more stubborn bits and pieces (like tartar).

So let's look at the various things toothpastes claim to do.

Flouride: This is supposed to help strengthen/build enamel. The consensus seems to be whatever you do, get a toothpaste with flouride. The primary difference in prescription Prevident appears to be a higher dosage of flouride (1% instead of 0.25%).

Whitening: This is essentially a sandpaper process. You're literally grinding away the stains. No thanks for me. If you have sensitive teeth and/or don't have severe staining problems, stay away.

Sensitive: Toothpastes containing potassium nitrate (saltpetre) are "clinically proven to sooth exposed dentin". Apparently bacon is good for your teeth! (Actually, bacon is usually cured with sodium nitrite these days.) From my googling, it seems this is primarily good for sensitivity at the base, along the gumline, only. I have noticed sensitivity there of late, but I'm much more sensitive (and have been for years) on the actual chewing surface of my teeth. I might give this a try.

Sodium Lauryl Sulfate: Most commercial toothpaste have this foaming agent. It is claimed to aggravate canker sores, so if you tend to get them you might look for a toothpaste without SLS (probably at a health food store).

RDA: see chart linked to above. A lower RDA means less enamel worn away. Ideally you find a good PCR:RDA ratio, but I haven't been able to find a good source of PCR information.

Triclosan: Colgate Total has this antibacterial stuff that adheres to your teeth. It's supposed to be really keen. It's patented, but I hear the patent is running out this year, so maybe we'll see other brands using it (or maybe I'm misinformed).

ADA seal of approval: look for this, it means dentists think it's keen. Oh, and it also means that the toothpaste manufacturer jumped through the hoops and paid the money to get the testing done. So the lack of seal alone cannot be taken to imply a lack of quality, but the presence of seal implies quality (or that the ADA is corrupt).

Toothbrush: the stiffness of the bristles is a factor in the abrasion as well. If your teeth are sensitive it seems you probably want soft bristles.

In summary, I plan to find a toothpaste with flouride, a low RDA value, and an ADA seal. Maybe I'll try something with saltpetre and/or triclosan. I'll probably continue to use an Arm & Hammer brand because I like the taste and the orange tube is handsome.

Disclaimer: I am not a dentist, doctor, oral hygenist, dental assistant, or drug dealer. I sometimes forget to brush my teeth at night. In no way do I claim know what's better for your teeth than you do, let alone dentists and drug dealers. Feel free to learn from this post but don't come whining to me when your teeth fall out. That goes for any other random blogger on the internet, for that matter. For all you know, I could be a baking soda shill, supported entirely by the deep pockets of Messieurs Sodium and Bicarbonate.