Stannous fluoride is one of the primary desensitizing agents in sensitive toothpaste and it works by occluding exposed dentinal tubules.
We will explain the desensitization mechanism, factors that affect its efficacy, side effects, and alternative desensitizers. Of course, we’ll provide evidence for all of our statements with research studies.
Stannous fluoride (SnF2) is one of the 4 different types of fluoride that are used in toothpastes. It is composed of one tin (Sn) and two fluoride (F) molecules. It is the only fluoride variation which is bonded to a metal molecule.
- Stannous fluoride
- Sodium fluoride
- Sodium monofluorophosphate
- Amine fluoride (available in swiss toothpaste Elmex)
Examples of toothpastes with SnF2:
- Colgate total
- Crest pro-health
- Sensodyne rapid relief
While the primary use of all fluorides in dentifrices is for its anti-cavity effects, stannous fluoride is unique in that it also has a desensitizing effect on teeth. All of its anti-hypersensitivity properties are due to the Sn (tin) that is bonded to the fluoride.
Examples of SnF2 toothpastes:
Note: Sodium fluoride normally does not desensitize teeth in toothpaste formulations. However, it can desensitize them when it is in a concentrated form such as in fluoride varnish.
How it works
Sensitive toothpastes with stannous fluoride can alleviate your sensitivity by occluding exposed dentinal tubules. In other words, SnF2 blocks external stimuli from interacting with the tooth nerve thus preventing your teeth from being sensitive.
To be crystal clear, it does NOT depolarize the nerve and numb the tooth like potassium nitrate toothpastes. That desensitizer works via a completely different mechanism.
How stannous fluoride occludes dentinal tubules
Stannous fluoride occludes exposed dentinal tubules by forming a deposit consisting of tin, zinc, phosphate, and silicon that blocks the orifice.
Source of deposit components:
- Tin – Another name for stannous fluoride is Tin (II) fluoride because tin is Sn on the periodic table of elements. Yes, it comes from the toothpaste.
- Zinc – This essential mineral is naturally present in the saliva and blood.
- Phosphate – This mineral is present in the saliva as a salivary buffering mechanism. It is also a main component of your tooth mineral, hydroxyapatite.
- Silicon – A mild abrasive that is present in most toothpastes and is used to remove stains from the enamel and whiten teeth.
Basically, this tin complex will clog the open tubules which lead directly to the tooth nerve.
How blocking tubules reduce teeth sensitivity
Individuals who suffer from chronic teeth sensitivity often have open dentinal tubules that are completely exposed. You can compare that to people without sensitivity who do not have exposed tubules.
The difference in why one has sensitivity while the other doesn’t is due to the presence of a smear layer that covers the orifices of the dentinal tubules.
The way stannous fluoride works in decreasing sensitivity is by recreating that missing smear layer by clogging up the orifices with a tin complex. This new deposit acts as a physical barrier that prevents stimuli from interacting with the tooth nerve.
As an additional perk, this new smear layer is more acid resistant than the original one thus strengthening the tooth.
Open tubules result in hypersensitivity
The open dentinal tubules can cause teeth sensitivity because it can detect changes in fluid movements within the tubules.
According to the hydrodynamic theory of dentinal sensitivity, your tooth has receptors that can sense these fluid movements. A pain signal is generated when it senses the fluids being pulled towards or away from the tooth.
Does it work?
Yes, stannous fluoride in toothpaste is effective in alleviating sensitivity by reducing the symptoms. There has been a plethora of research studies that have demonstrated its efficacy.
A study from the Journal of the American Dental Association, found that it can significantly reduce dentinal hypersensitivity after 8 weeks of use when compared to a placebo.
- Stannous fluoride occluded 82% of the open tubules vs the placebo’s 35%.
- Improvements in tactile dentinal hypersensitivity scores of 27.8% and 42.0%.
- Improvements in air blast hypersensitivity scores of 21.4% and 32.3%.
A study by Proctor & Gamble found that stannous fluoride based toothpastes were superior to sodium fluoride ones in reducing dentinal hypersensitivity when used twice daily.
- Air test results – 24% improvement at 2 weeks and 68% at 8 weeks.
- Tactile test results – 114% improvement by week 2 and 184% at 8 weeks.
In summary, there were statistically significant differences in all measures of sensitivity from using a SnF2 toothpaste. There was a marked reduction in symptoms by 2 weeks of use but it continued to improve up to the 8 week mark.
Factors affecting efficacy
While stannous fluoride as a desensitizing agent has been proven, there are other factors which can affect its efficacy during daily use.
Factors increasing efficacy:
- Brushing for at least 2 minutes.
- Applying toothpaste towards gum line.
- Reducing acidic foods.
- Brushing after every meal.
- Not rinsing after brushing.
Factors decreasing efficacy:
- Brushing for less than 2 minutes.
- Not applying toothpaste at gum line.
- Diet high in acidic foods.
- Inconsistent use of toothpaste, brushing less than twice a day.
There are three points we wish to expand upon due to their overlooked importance.
Applying toothpaste towards gum line
The vast majority of exposed dentinal tubules occur near the gingival margin (gum line). That is the area where gum recession tends to occur which results in exposed root surfaces that are incredibly sensitive.
If you’re not brushing the toothpaste into this sensitive spot, you’re essentially missing the entire point of using desensitizing toothpaste. Like what exactly are you trying to desensitize if not the most sensitive spot?!
Reducing acidic foods
The tin complex from stannous fluoride will recreate the smear layer and plug up the open dentinal tubules. However, all of your efforts can become undone if you consume an excessive amount of acidic foods.
- Fruits and juices
- Sodas & sport drinks
- Sugary beverages and foods
- Sour & spicy foods
What the acidity does is dissolve the newly created smear layer thus bringing you back to square one. If this is your situation, it may not be the toothpaste’s fault but rather your lifestyle habits that are sabotaging your own efforts.
Don’t rinse after brushing
We do endorse rinsing after brushing your teeth because you’re not supposed to swallow fluoridated toothpaste. However, the NHS does recommend not rinsing afterwards in order to reap the full effect of fluoride.
We find NHS’s recommendation to be impractical on a daily basis because you have to continually spit out toothpaste if you don’t rinse. However, if you needed an extra boost in desensitization from stannous fluoride you should consider not rinsing afterwards.
Doing so will allow the toothpaste to desensitize them for a longer period of time.
The two major potential adverse effects with using stannous fluoride in sensitive toothpastes are teeth staining and an allergy to it.
One of the earliest studies that noticed this adverse effect was in a 1982 study in the European Journal of Oral Sciences. A yellow-golden stain was found on the teeth of the experimental rabbits that used stannous fluoride.
- The Tin (Sn) of stannous fluoride (SnF2) was interacting with the sulfhydryl groups to form stannic sulfide, which caused the tooth staining.
- The sulfur in our mouth comes from the pre-existing bacteria, which are also responsible for bad breath due to the volatile sulfur compounds (VLCs) that are produced.
All of this may sound disheartening but the good news is that there has been advancement in recent technology. According to a study in the Journal of the American Dental Association, the newer stannous fluoride toothpastes have reduced teeth staining compared to the prior iterations.
However, you should be cognizant that they used the word “reduced” and not “eliminated”. That implies that it still does stain but just not as bad as before. This is an improvement and we should all be grateful for it! Perhaps in the future they will completely get rid of the yellowing.
While having a tin allergy may be rare it is possible. If you do, you most likely will not be able to tolerate stannous fluoride toothpastes since it consists of tin.
- Swollen gums
- Difficulty breathing
If you experience any of the above symptoms you should discontinue use of the toothpaste immediately. You may want to explore alternative desensitizing agents.
Stannous fluoride is but one type of desensitizer in sensitive toothpaste. There are in fact many mother types of desensitizers that can potentially work even better for you. The effects can be individualistic so if one isn’t working for you, you should try another one.
Other desensitizing agents in toothpaste:
- Potassium nitrate. A nerve depolarization agent that numbs the tooth nerve instead of occluding dentinal tubules.
- Hydroxyapatite. Toothpaste made of tooth mineral, it works by blocking exposed dentinal tubules by inserting itself directly into it.
- Strontium chloride. Tubular occlusion agent which used to be in Sensodyne toothpastes but has since been replaced by potassium nitrate.
- Arginine. Another tubular occlusion agent which Colgate used to make but is no longer available in the US. You can still find this toothpaste in their overseas market.
Downsides to using SnF2
There are two downsides to using stannous fluoride toothpaste for decreasing dentinal hypersensitivity.
- More costly. If you compare the price of stannous fluoride with sodium fluoride toothpastes, you’ll notice a price premium. While the sodium version is relatively inexpensive you should expect to pay more for the stannous version.
- Requires continual use. If you stop using this toothpaste, the desensitizing effect will wear off. The reason is because as you eat, the decrease in mouth acidity will melt away the newly created smear layer. You must brush again to re-block these re-exposed tubules in order to maintain the desensitization.
Stannous fluoride will not only prevent tooth decay but also alleviate teeth sensitivity by occluding exposed dentinal tubules. This blocks stimuli from triggering sensitivity signals.
However for the desensitizing effect, you should expect to use it continuously long term. You must brush with it at least twice a day for two minutes each. If you stop using it, you will lose the protective desensitizing effect.