Teeth Whitening and Dental Bleaching
Tooth whitening is the process of gently removing unsightly stains from the outer enamel coating of your teeth. When we restore your teeth to their original shade of brightness, we call the process teeth whitening. If we exceed that original brightness to create a truly gleaming smile, we call the process dental bleaching.

The term “whitening” refers to removing superficial stains on enamel. When you see OTC products claim whitening effects it’s usually through some form of abrasive, ie: silica, that is a stain remover. Bleaching, however, is much different.

There are several techniques for bleaching teeth. The most common technique is the application of a peroxide-based whitening agent. Peroxides are powerful chemical oxidizers, and they attack the staining material. At home teeth whitening kits that are sold in stores contain peroxide gels that are applied to the teeth and allowed to react for a specified period of time. The gel is sometimes embedded in strips that adhere to your teeth for periods as long as overnight.

Most patients also find that at home treatments are actually more expensive than an in-office teeth whitening by a dentist. Although the initial at home treatment may cost much less, the whitening agents are less concentrated than those used by dentists. The whitening gels usually contain either hydrogen peroxide or carbamide peroxide. The gels applied in-office typically contain 15 to 43 percent peroxide and are significantly stronger than the gels found in at-home whitening kits.

High concentrations of hydrogen peroxide are sometimes used in a procedure known as power bleaching. With this technique, a protective barrier is applied to your gums, and a gel that combines a high concentration of hydrogen peroxide with a catalytic photochemical is applied to your teeth. A light source is then used to trigger the catalyst in a process known as activation. The catalyst causes the rapid degradation of the hydrogen peroxide in the gel into highly-reactive free radicals that oxidize the stains on your enamel and almost instantly whiten your teeth.

PAP, or 6-phthalimido peroxy hexanoic acid, is another chemical bleaching agent that is sometimes used to whiten teeth.

How Your Teeth Lose Their Natural Whiteness
Tooth enamel is the hardest material in your body, but it isn’t impervious to stains. The enamel, at the microscopic level, is made up of very tightly packed rods. Each rod is a crystal of a mineral known as hydroxyapatite. These crystalline rods have microscopic crevices between them, and the crevices expand fractionally in response to hot temperature or an acidic environment.

Extrinsic Discoloration
Extrinsic stains of your teeth occur on the outer surfaces of the enamel. “Outer” is a relative term in this case. Some staining material does adhere to the surface of the enamel, but the majority of the discoloration is due to materials being deposited into the microscopic crevices between the crystalline rods of the enamel. Over time, these microscopic deposits build up and result in a visible layer of discoloration. The good news is that these staining materials are not chemically bonded to the enamel in any way, and they are relatively easy to remove with the application of chemical agents that can get down into the same microscopic spaces. The free radicals formed by the dissociation of hydrogen peroxide are the perfect size for the job.

The materials that build up into stains come from foods and liquids that you ingest. Drinks like red wines, coffee and teas contain colored chromophores that adhere to tooth enamel and get into the spaces between its crystalline rods. Foods like cherries and blueberries contain these same kinds of molecules.

Soft drinks and other acidic liquids, and also hot beverages like coffee or tea, cause a fractional expansion of the crevices between the hydroxyapatite rods of the tooth enamel. The slight expansion facilitates the entrance of staining materials.

Even foods that lack chromophores can create extrinsic discoloration. Bacteria in your mouth eat these foods even as you do, and they produce a darkly colored byproduct that can adhere to the enamel and cause a stain.

Tobacco, whether chewed or smoked, is also known to stain teeth yellow or even brown. Poor dental hygiene is another common cause of discolored teeth. Tartar builds up on the outer surfaces of teeth without adequate brushing and flossing,
and the tartar build-up is more easily stained than tooth enamel.

Intrinsic Discoloration
Intrinsic discoloration occurs on the inside of your teeth. It may be inside the enamel, or it may be a discoloration of the dentin layer that lies beneath the enamel, or it may even be a darkening of the living dental pulp that fills the center of the tooth. Unlike the extrinsic stains caused by materials that adhere to the surface of the enamel without chemically bonding to it, intrinsic stains result from chemical changes to the tooth’s structure. These discolorations are difficult to reverse, and in some cases they cannot be removed.

Intrinsic discoloration can be caused by high fluoride concentrations in drinking water consumed as a child. Before a child’s adult tooth emerges, the enamel is not fully formed. Fluoride, if present in high enough concentrations, can become incorporated into the crystal structure of the enamel as it is formed in the same way that the inclusion of an impurity can cause a gemstone to take on a specific color. While impurities in gems often result in beautiful color variations, the inclusion of fluoride into hydroxyapatite crystals results in an unpleasant brown enamel. Fluoride has no effect of fully formed adult tooth enamel.

Certain medications, such as tetracycline and its derivatives, can cause intrinsic discoloration of tooth enamel when administered to children. Again, this is because the enamel of pre-emergent teeth is not fully formed.

Tooth decay, dental trauma, and specific congenital deformities are also causes of intrinsic discoloration in adult teeth. The bacteria responsible for tooth decay damage the enamel and create discolored byproducts. Infections in the dental pulp can also create discolored byproducts. Injury to a tooth, if severe enough, can rupture blood vessels within the living dental pulp and release blood that deteriorates into a dark stain inside the tooth.

What Can Teeth Whitening Correct?
The process of teeth whitening can recover your beautiful smile when your teeth have extrinsic stains. Fortunately, the majority of stains fall into this category. In some cases, teeth whitening can also restore damage caused by intrinsic discolorations. The applicability of the whitening process is determined by the root cause of the discoloration.

Degraded blood products from an injury to the tooth can be deposited into the dentinal tubules of the dentin layer. A process known as non-vital bleaching can sometimes be used to bleach away these intrinsic stains.

When the stain is a mild discoloration of the enamel caused by administration of tetracycline to a child, a process known as vital bleaching can sometimes give good results. Vital bleaching involves the application of highly concentrated hydrogen peroxide with activation by a heat source.

Unfortunately, tooth whitening is not effective against most other causes of intrinsic discoloration. Porcelain veneers are usually applied in these cases.

Why Is Teeth Whitening Important To A Dental Smile Makeover?
A smile makeover can have many steps. Teeth may need to be widened, lengthened, or repositioned to provide the optimum ratio of width and depth and support for the lips. The underlying purpose for a smile makeover is to showcase your gleaming, movie-star smile. If your teeth aren’t white, your smile makeover will be drawing attention to a part of you that you probably don’t want to show. This is why teeth whitening is the fundamental step of the smile makeover.

When you have a bright smile, you will find yourself smiling more often. It’s an old saying that “when you smile, the whole world smiles with you.” That saying has been around a long time because it’s true. When people around you see you smile, they will smile back at you. People who smile appear to be happy and confident, and simply having the appearance of happiness and confidence can actually make you happier and more confident as doors open that might otherwise have been closed to you.

How Does Teeth Whitening Work?
Teeth whitening is a chemical bleaching process. There are multiple variations of the process, but all of them work by placing an oxidizing agent into contact with discolored teeth. The oxidizing agent chemically attacks the stain and draws away electrons. As the molecular geometry of the staining material changes, it is chemically changed so that it either no longer darkens the surface of your teeth or is unable to adhere to the enamel. The various whitening processes differ from one another in the specific oxidant used and in the way it is introduced to the stain.

At-home Teeth Whitening
At-home teeth whitening treatments use a weak peroxide to attack the stains on your teeth. If you follow the instructions carefully, they are fairly safe to use. Ironically, it is this very safeness that can create a danger. Because the peroxide concentrations are low, the stain is removed gradually. Users often want more rapid results and damage the enamel by leaving the chemical on longer than directed.

In-office Teeth Whitening
In-office teeth whitening can be thought of as the heavy duty, industrial version of teeth whitening options. It provides visible results almost immediately. Dentists use stronger bleaching concentrations than at-home whitening kits and are trained use them without harming your teeth. They can apply protective coatings to your gums to prevent gum tissue from being bleached of color along with your stained tooth enamel, and they have the means to activate the bleaching agents so that your teeth become whiter faster.

Light is usually used to activate the whitening agents. Some dentists use lasers, but the lasers are only used to activate the whitening agent so that it reacts with the stain more quickly. The lasers alone cannot remove the stains.

Is Teeth Whitening Worth It? A Cosmetic
Dentist’s POV

Bleaching, either at home or professionally are an easy, non-invasive first step towards beautifying your smile. For some people it might be exactly what they desired, for others it will show them they may need to consider the next step towards their smile.

One thing that all of these patients have in common, no matter the dental problems they are experiencing, is that they rarely smile. I can walk through a crowded gathering of people and instantly pick you out if you have misshapen or discolored teeth. You will be the one curving your lips upwards at the corners without ever
fully smiling.

I am a dentist, so I see you not smiling and instantly suspect that you have a dental problem that you want to keep hidden. When non-dentists see you, however, they may very well take away a different impression. Will they think you are unsociable? Will they find you unfriendly? What if they are a hiring authority for a lucrative job opening or a loan officer at a bank?

Smiles are far more important than most people realize. Take a look at this set of before and after photos and ask yourself how you feel about the person in each picture.