Teeth Whitening Sensitivity - Causes and How to Treat It

A whiter smile is a popular accessory for almost everyone today. From in-office procedures to dentist-prescribed at-home treatments to trademarked boxes of strips, gels and goos at the store or online, if you want a whiter smile, there's a method and a price point for everyone.

But the fact is, with any method, you're applying a bleach formula directly to your teeth and gums; and bleaches are powerful solutions that can cause discomfort if not handled properly.

Dental sensitivity is the most common issue surrounding teeth whitening-and it can happen to anyone, with almost any method. But, according to Dr. Rod Kurthy, DDS, a recognized expert in the field of whitening science, "how severe the reaction is depends on each individual and three important factors: genetics, bleach stability and acidic reaction."

What Makes Teeth Sensitive?

Inside every tooth are millions of microscopic "dentinal tubules" that extend from the nerve (pulp) inside the tooth to the outside surface of the tooth. There's fluid inside these tiny tubes, and when this fluid moves inside the tubes, it causes sensitivity. Minerals from saliva normally plug up the open outer ends of the tubes, preventing fluid movement and sensitivity. All bleaching gels tend to dissolve these "plugs" [Fig. 1] , allowing the fluid in the tubes to move and cause sensitivity [Fig. 2].

Genetics

For some people the reaction is minor, but for others the reaction can be very painful - and that's where the subject of genetics comes into play. It seems that everyone has a different reaction. Fair-haired and fair-skinned folks (you know who you are, you "burn" instead of "tan") tend to experience the highest degrees of sensitivity. But people with various dental problems are also at risk (that's why so many dentists recommend a thorough exam and history before moving forward with powerful teeth whitening techniques.) Genetics can play such a major role in dental sensitivity that some people may never be good candidates for teeth whitening although there is significant progress in addressing this problem.

Bleach Stability

Just think about how strong a whitening gel has to be to actually change the color of your teeth. It's no surprise then that manufacturing dental-grade bleach formulas for oral applications is a tricky science. And it's hard to get it right; make them too powerful and they're hard to keep at peak strength throughout the blending, shipping and storage process. Make them too weak and they won't work at all. That's why the people who make whitening formulas aim for something in the middle - literally - the goal of most whitening gel scientists is to create a shelf-stable bleach with a completely neutral acid/alkaline ratio or pH.

It's hard to do though - so frequently bleaching gels are just a bit off "neutral." What this means for the little tubes in your teeth is this-if the bleaching gel is too acidic, it can dissolve the plugs at the end of your tubes even more, leading to more sensitivity.

So, if you're thinking about whitening your teeth with an unknown over-the-counter method or manufacturer, consider how much science really goes into your more beautiful smile. Then reconsider.

Acid Reaction

The overall action of bleach on enamel, dentin and gums is the big daddy cause of most sensitive reactions; and the one most people are familiar with. Minor dental problems (chips, cracks, decay) or daily living and consumption of acidic foods and beverages (such as some sodas, sour candies and overabundance of fruit) can weaken tooth enamel (or create small openings in enamel) to make it easier for acids to reach the inside of the tooth and dissolve the little plugs at the end of your tubes. That's why good hygiene and a good diet make a difference in keeping sensitivity at bay. Regular cleaning, flossing (plaque removal) and examination catch small issues as they occur - minimizing the chance for damage to the inside of your teeth.

How to Treat Teeth Whitening Sensitivity

Because sensitivity is such a big issue in the world of teeth whitening, there's a lot of interest in solving the problem-or at least in providing sensible, affordable and reliable ways to eliminate or minimize the discomfort.

Desensitizing agents can be found in the formulas of whitening solutions and are also used as stand-alone medications that dentists apply during a whitening procedure. Popular stand-alone desensitizers include: UltraEZ® Desensitizing Gel Syringe (with Fluoride and Potassium Nitrate) and Orajel Advanced Tooth Desensitizer. Some dentists utilize desensitizing methods after whitening; one system now performs desensitizing techniques before and after (KöR Whitening Deep Bleaching^TM).

Fluoride is probably the most commonly used desensitizing agent. It acts on your dentinal tubes to temporarily reduce their size, slightly reducing the fluid movement in the tubes.

Potassium nitrate is another popular agent. It actually works its way into the center of your tooth (the pulp) and has a numbing action that may reduce discomfort. It tends to work better on some than others. However it doesn't do anything to reduce the tooth nerve inflammation caused by fluid movement in the tubes.

There's more and more research into the use of a compound called amorphous calcium phospate (ACP). ACP helps to strengthen the enamel, but seems to do little to plug the open ends of the dentin tubes.

Desensitizers that rapidly build new plugs [Fig. 4] in the open-ended tubes [Fig. 3] have shown to be the most successful at stopping fluid movement in the tubes and preventing bleaching sensitivity. These desensitizers are oxalates (minerals) and HEMA (resin) based products (KöR Whitening desensitizers).

If desensitizers are not fully successful, over-the-counter anti-inflammatories may be used. If "anti-inflammatories" sounds too medical, just remember ibuprofen or Aleve. These classes of pain relievers work to minimize inflammation of irritated tooth nerves - which, in turn, helps to reduce additional discomfort and sensitivity some people may feel. If you experience inflammation, your dentist may give you something before and/or after your procedure - or recommend that you follow through at home.

Having a whiter smile can create real feelings of confidence and self-esteem for people, but alongside the advantages may come the discomfort of sensitivity. But, with a little education and awareness, you can help to make sure you experience the brighter side of whitening - whether you opt for do-it-yourself techniques or seek the help of your dentist. Keep smiling!