Ready for a bit of science? Here are some teeth whitening facts, to explain the chemical process. I'll try to keep it simple! But first, why do teeth become dull over time? What makes them look dark?
An explanation of teeth whitening facts must make plain that tooth enamel is NOT solid, like your kitchen sink!
In fact, it is microscopically like a sponge, with lots of tiny pores and channels going straight down into the tooth.
Over time, things like tea, coffee, dark sodas, highly colored foods, cigarette smoke etc. all contribute to a slow build-up of tiny molecules deep inside the enamel.
These molecules gradually get bigger and bigger. Long-chain molecules are very dark, and the bigger they get, the darker they get. Still with me?
So, what is teeth whitening?
Teeth whitening is a bleaching process that removes the microscopic stains in tooth dentine and enamel. The active ingredient is hydrogen peroxide. This means that if your teeth are quite white already, then they will not whiten up much more unless you use one of the best teeth whitening products.
Any teeth whitening product breaks down to hydrogen peroxide. The molecular oxygen, oxygen ions and oxygen radicals are responsible for whitening, and I call these by-products "bleaching factors".
Teeth whitening has two distinct phases:
1. Oxygenation. This is the "scrubbing bubbles" action that actually starts to break up debris in the surface of the tooth enamel, and REMOVE that staining debris. This takes time to really start getting into the enamel.
2. Conversion. This is where oxygen ions and especially oxygen radicals break up the long-chain stain molecules into millions of tiny molecules.
When the oxygen radicals break down these large molecules, the resulting smaller molecules appear colorless or white. So NOW the teeth start to look whiter!
So here's the problem;
It takes TIME to condition the teeth by removing the debris in the surface of the tooth enamel. You have to get this microscopic debris out of the way before the oxygen radicals can get deeply into the enamel of the tooth, to break down those big dark molecules into smaller, colorless ones.
This is precisely why one-hour chairside bleaching often shows little or no results.
There just isn't enough time to get rid of the debris within the surface tooth enamel, and then break down those deeper, big dark molecules.
This is why I prefer a home whitening technique. At most, I use a one-hour chairside session for the "oxygenation" step. Then the home whitening is faster.
Now let's talk about products and why cheap products cause problems.
Sorry, there's a bit more science to teeth whitening facts!
Bleaching gels are unstable chemicals; they are supposed to be! This is why they can break down so quickly and release their bleaching factors. The downside is that they start breaking down immediately after they are manufactured!
So bleaching product companies must find a way to stabilize them to provide some shelf life. There are only three ways to do that:
I WARNED you there was some more science! Don't worry, we're almost there for teeth whitening facts!
1. Constant refrigeration is very expensive for bleaching product companies. You are talking about refrigeration at the factory immediately after manufacture.
Then refrigerated trucks or airplanes to the bleaching product company from the factory. Then in refrigeration at the bleaching product company. Then shipped with thermally insulated containers with cold packs from the bleaching product company to the dentist.
2. "Anhydrous" stabilizers can be added to stabilize the bleaching gels, but there are major problems with this.
First, if you stabilize the gel for the purpose of shelf life, then this means that the bleach is too stable when placed on the teeth, and it doesn't work nearly as well!
3. Adding acidifiers results in an acid bleaching gel. But there's a problem. On its own, hydrogen peroxide tends to become more acidic anyway as it breaks down. If you START with an acidic gel, it becomes even MORE acidic as the gel breaks down to release oxygen!
Also, adding acids to the gel slows down the reaction, and so you don't get much whitening, AND the acid gel attacks the tooth enamel.
Guess how ALL cheap bleaching gels are stabilized?
Yes, you guessed it, they're anhydrous and acidic. This means that they do NOT whiten teeth very well, and they tend to cause a LOT of sensitivity.
So, to sum up this list of teeth whitening facts:
To get effective teeth whitening with minimal sensitivity, you have to use a product that has been formulated well and been kept cool the whole time!
This tends to be more expensive than the cheaper gels, but like anything else in life, "you tend to get what you pay for! "