Baking Soda and Abrasive Toothpastes

by Feb 25, 2019

I’ve receive several questions from patients about the use of baking soda

(sodium bicarbonate) as an alternative to commercial toothpaste, and especially regarding its claimed ability to whiten teeth.

Searching the Internet regarding brushing your teeth or whitening your teeth with baking soda, 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. Baking soda is NOT abrasive.

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.

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 much harder than glass. When 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 = 5
  • Tooth dentin/root = 3
  • Baking soda = 2.5
  • Hydrated silica in toothpaste = 5-7

Baking 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 70-100
  • High 100-150
  • Harmful 150-250

The FDA limits abrasiveness to a maximum of RDA 200.

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.

Baking Soda To Whiten Your Teeth

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!

The Really Dangerous Information

Often you’ll find instructions to add lemon juice, apple cider vinegar or some other acidic ingredient along with the baking soda. It’s the acid that attacks the enamel! This a perfect way to “wear away your tooth enamel.

Yes, this maybe a “natural” way of whitening you teeth, however, a snake bite is natural too but isn’t healthy!

RDA Values

Toothpaste Brand and Variety

Source

0

non-alcoholic mouthrinse (Biotene PBF(*Green Label), Act II Anticavity, Crest Pro-Health Complete, Oasis, Listerine Zero, Peridex, Peroxyl and water)

Church & Dwight

7

straight baking soda (The Arm & Hammer Yellow Box)

8

Arm & Hammer Tooth Powder

Church & Dwight

23

Biotene PBF Drymouth Toothpaste

25

Pronamel

30

KID’S TOOTH GEL STRAWBERRY-RASPBERRY (ph value: 7.0-7.5)

Lavera

30

Elmex Sensitive Plus

Elmex

42

Arm & Hammer Peroxicare Tartar Control

Church & Dwight

42

Arm & Hammer Advance White Baking Soda Peroxide

Church & Dwight

42

Arm & Hammer Peroxicare Regular

Church & Dwight

45

Oxyfresh

44-53

Squigle Enamel Saver

49

Arm & Hammer Peroxicare Tartar Control

Church & Dwight

49

Tom’s of Maine Sensitive (given as 40’s)

Tom’s

53

Rembrandt Original (RDA)

Rembrandt

53

CloSYS

57

Tom’s of Maine Children’s, Wintermint (given as mid-50’s)

Tom’s

60

Boiron Homeodent Natural Toothpaste-Lemon Flavor

62

Supersmile

Supersmile

62

Clinpro 5000 Fluoride Toothpaste

63

Rembrandt Mint (‘Heffernan RDA’)

Rembrandt

63

Biotene Regular

68

Colgate Regular

Colgate- Palmolive

70

Colgate Total

Colgate- Palmolive

70

Arm & Hammer Advance White Sensitive

Church & Dwight

70

Colgate 2-in-1 Fresh Mint (given as 50-70)

Colgate- Palmolive

70-76

Squigle Tooth Builder

79

Sensodyne

Colgate- Palmolive

80

AIM

Unilever

80

Close-Up

Unilever

83

Colgate Sensitive Maximum Strength

Colgate- Palmolive

85

Biotene Sensitive

91

Aquafresh Sensitive

Colgate- Palmolive

93

Tom’s of Maine Regular (given as high 80’s low 90’s)

Squigle (Tom’s)

94

Rembrandt Plus

Rembrandt

94

Plus White

Indiana Study

95

Kid’s Crest

95

Crest Regular (possibly 99)

P&G (P&G)

101

Natural White

Indiana Study

103

Mentadent

Squigle

104

Sensodyne Extra Whitening

Colgate- Palmolive

104

Sensodyne Repair and Protect with Novamin (Purchased on Amazon.com)

GSK Pharmaceuticals

106

Colgate Platinum

Indiana Study

106

Arm & Hammer Advance White Paste

Church & Dwight

107

Crest Sensitivity Protection

Colgate- Palmolive

110

Colgate Herbal

Colgate- Palmolive

110

Amway Glister (given as upper boundary)

Patent US06174515

112

Prevident 5000 Booster

113

Aquafresh Whitening

Indiana Study

117

Arm & Hammer Advance White Gel

Church & Dwight

120

Close-Up with Baking Soda (canadian)

Unilever

124

Colgate Whitening

Indiana Study

130

Crest Extra Whitening with Scope

Indiana Study

130

Crest Pro-Health with Scope (Crest for Me)

Burt’s Bees, Inc.

133

Ultra brite (or 120-140)

Colgate- Palmolive

144

Crest MultiCare Whitening

P&G

145

Ultra brite Advanced Whitening Formula

P&G

150

Pepsodent (given as upper bound)

Unilever

165

Colgate Tartar Control (given as 155-165)

Colgate- Palmolive

189

Crest Pro-Health

P&G

200

Colgate 2-in-1 Tartar Control/Whitening or Icy Blast/Whitening (given as 190-200)

Colgate- Palmolive

200

recommended limit

FDA

250

recommended limit

ADA

To measure RDA in the lab, the tester starts with extracted human or cow teeth. The teeth are irradiated in a neutron flux, mounted in methyl methacrylate (bone glue), stripped of enamel, inserted into a brushing-machine, brushed by ADA standards (reference toothbrush, 150g pressure, 1500 strokes, 4-to-1 water-toothpaste slurry). The radioactivity of the rinse water is then measured and recorded. For experimental control, the test is repeated with an ADA reference toothpaste made of calcium pyrophosphate, with this measurement given a value of 100 to calibrate the relative scale.

Consumer Reports reviewed toothpastes (August 1998). Unfortunately, they did not consider RDA, only stain removal. So, high-abrasivity toothpastes like Ultra brite got the best ratings. I think you should be skeptical of their rankings. Which toothpaste is the best? Almost every dentist I know swears by Colgate Total, because it has a long-lasting antimicrobial ingredient. But in reality maybe no toothpaste is best for some people, depending on the relationship of enamel to root to sulcus (i.e. root coverage).

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