In a world filled with whitening toothpastes and drugstore whitening kits, it’s important to know that the most effective teeth whitening treatment still comes from your dentist. Not only do dentists have more powerful tools at our disposal, we are also experts on your smile, and can tell you whether teeth whitening is right for you and what kind of results to expect.

To understand how to whiten teeth as effectively as possible, let’s start with a little science.

If you look at teeth under a microscope, you can see that the hard outer layer, called enamel, is made up of a tightly packed crystal structure called rods. While this layer seems solid and smooth to the naked eye, it’s possible for the molecules that cause stains to get deep into the enamel by seeping between the rods. In order to remove stains, dentists use a chemical that can get down to where the stains are and break up them up using a chemical reaction.

The chemicals used in professional teeth whitening are hydrogen peroxide and carbamide peroxide (which breaks down into hydrogen peroxide in your mouth, so hydrogen peroxide is still the active ingredient). Hydrogen peroxide penetrates the teeth and causes a reaction called oxidation, which breaks down the stain compounds.

By the way, whitening toothpastes work by removing surface stains on teeth, not the ones under the surface. They do this by being more abrasive than other toothpastes, which is why your dentist may discourage you from using whitening toothpastes if you have complained of tooth sensitivity. More than anything, toothpastes are good for preventing stains, not removing them!

At-home teeth whitening products from the drugstore also contain carbamide or hydrogen peroxide, but in much lower concentrations. They also contain other ingredients for flavor and to help reduce the possibility of tooth sensitivity. While drugstore kits are much cheaper, because the bleaching agents in these kits are less potent, you can expect to see results in weeks as opposed to days (with a home kit from your dentist) or minutes (when you get your teeth bleached at the dentist).

Another reason that it’s a good idea to go to you dentist for whitening treatments is they can evaluate whether your teeth should even undergo whitening to begin with. Some people don’t realize that whitening only works on natural teeth. Fillings and crowns are made of artificial materials that look like teeth, and feel like teeth, but chemically speaking, they’re very different. Most restorations are made from ceramic, porcelain, or composite resin. These materials do not react the same way to bleaching chemicals as your natural tooth enamel does. If you have large fillings or crowns, a dentist can recommend alternatives to bleaching for improving the appearance of your smile.

The professional teeth whitening process starts with a consultation with your dentist. Not everyone is a good candidate for teeth whitening, which is why you want to talk to a dentist before you have it done. If you have large fillings or crowns (caps) on your front teeth, teeth bleaching is not a good idea. The chemicals will bleach your natural teeth but not your dental restorations (which are made from ceramic, porcelain or composite material), resulting in your teeth being different colors.

Teeth whitening is most effective on yellow discoloration, and can be less effective on brown or gray discolored teeth, especially when the discoloration is the result of exposure to tetracycline antibiotics while teeth are still developing (before age 8).

Next comes the actual whitening appointment. Once you’re comfortable in the chair, the dentist will insert a lip retractor into your mouth, which is just a plastic guide that moves your lips out of the way so your teeth are easy to access.
The dentist will then cover your gums around your front teeth with a gel and then harden it with a high-powered light. This is called a gingival barrier, and it protects your gums from the teeth bleaching chemicals during the whitening process. The dentist may also apply a compound to your teeth that will help prevent tooth sensitivity.

The actual whitening process involves the dentist applying a gel made of 15% to 35% hydrogen peroxide to your front teeth. Hydrogen peroxide can penetrate the porous outer layer of your teeth and break apart stain compounds using a chemical reaction called oxidation. Depending on the whitening system being used, the application of the whitening gel may be followed by applying a high-powered light that speeds up the whitening process.

Most systems involve multiple applications of the gel throughout the whitening session. The dentist will rinse off the gel and reapply a fresh coat as many times as necessary within the space of about 40 minutes. Once complete, the whitening procedure can achieve four to six shades of whitening after only one session. Some patients experience tooth or gum sensitivity after whitening, but this usually goes away within a day or two.

While the effects of teeth whitening can last quite a while (months to years), depending on diet and other habits (like smoking!), the stains on teeth will eventually return. Some dentists may recommend maintaining a freshly whitened smile with a professional home whitening kit. These kits include custom made trays to fit your teeth and tubes of whitening gel that has a lower concentration of bleaching agents than the in-office variety. The patient lines the trays with the gel and wears them for a few hours at a time each day or while sleeping.

When it comes to teeth whitening, you get what you pay for. While over-the-counter kits from the drugstore are cheap and offer the convenience of at-home bleaching without a visit to the dentist, they are slower and less effective than professional whitenings. And of course, without the supervision of a dentist, you don’t have the guidance you need to get the best results. If you want truly Hollywood-white teeth, invest in a professional teeth whitening administered by your dentist.

Teeth whitening is one of the quickest & least invasive ways to make a huge difference in the appearance of your smile. Most dentists offer either in-office teeth whitening, take-home teeth whitening kits, or both. The effectiveness of these whitening methods varies slightly, but the way they work is generally the same.

While many people refer to teeth whitening as bleaching, it’s important to know that the dentist doesn’t use the same chemical to whiten your teeth that you use to whiten your laundry! Laundry bleach is a chemical called sodium hypochlorite that smells like chlorine, & it can be poisonous if ingested, so we don’t want it anywhere near your mouth! For teeth bleaching, two chemicals are commonly used: hydrogen peroxide & carbamide peroxide.

Even though the hard outer surface of your teeth, called enamel, seems solid, on a microscopic level, it is actually porous. Stains & discoloration on your teeth appear when compounds from the foods you eat (or from smoking) penetrate this porous enamel layer & accumulate there. Teeth bleaching works when hydrogen peroxide creates a chemical reaction that breaks apart the staining compounds.

During an in-office teeth cleaning, the dentist will first clean your teeth then apply a gel that contains 10 to 35 percent hydrogen peroxide. Sometimes a high powered light is then used to help speed up the chemical reaction. After leaving it on for several minutes, the dentist will remove the bleaching gel, then re-apply it. The entire whitening procedure usually takes about 45 minutes to an hour.

For at-home teeth bleaching, your dentist will take an impression of your teeth & creates soft dental trays. These trays are then filled with a thin layer of gel that contains 10 to 20 percent carbamide peroxide. (Carbamide peroxide breaks down into hydrogen peroxide & urea in the mouth, so the active bleaching agent in at-home kits is still hydrogen peroxide.) At-home bleaching trays are worn for a few hours during the day or while sleeping. Because they are less powerful, at-home systems take longer to achieve the same whitening effects as in-office systems.

Teeth bleaching is not a good solution for everyone. Because teeth bleaching is designed to treat stains on natural tooth enamel, patients who have tooth colored restorations (i.e. fillings or crowns) or veneers should not get their teeth whitened. Whitening compounds do not work on the ceramic or porcelain composites these restorations are made from, so the result is that teeth color may become mismatched. Teeth bleaching will also not work well on tooth discoloration that is the result of changes inside the tooth, below the enamel, such as grayish teeth caused by certain medications. For this reason, we always recommend that teeth whitening, whether at home or in-office, be performed under the supervision of your dentist.