Professional (in-office) whitening treatments - The procedure.

- An outline of the steps your dentist follows when they bleach your teeth.

tooth shade.

Link to Taking the Pre-treatment Shade step.

light in use.

Link to Whitener Application Step.

Although your dentist has a variety of different professional whitening systems to choose from, there's usually a standard set of steps that are performed when any one of them is used. That's what we've outlined on this page.

(In case you're wondering, the following terms are used to refer to the exact same procedure we cover on this page: Professional, in-office, power and laser whitening.)

In-office teeth whitening: The steps.

Step #1 - Cleaning your teeth.

Before making a decision to have whitening treatments performed, you should have a professional dental cleaning. All debris, surface staining and accumulated tartar should be removed.

While not necessarily expected, it's conceivable that this step alone may improve the appearance of your teeth enough that no bleaching treatments are needed.

Touch-up cleaning.

At the start of your whitening session, your dentist will buff your teeth with a polishing paste just to make sure that any stain or debris that's accumulated is removed.

Step #2 - Determining your pretreatment tooth shade.

Picture of using a dental shade guide.

Using a shade guide to document the pretreatment color of teeth.

Both you and your dentist will want to know how effective your bleaching session has been. In order to make this comparison, your dentist will need to document the pretreatment color of your teeth.

Using a dental shade guide.

Your dentist will compare samples from a shade guide (an assortment of tooth-shaped porcelain tabs, each of which has a slightly different color) with your teeth.

They'll determine which sample matches best and then make a record this value in your chart.

Takeaways from this section.

In some instances, they may further document your shade by taking a picture of your smile with the selected tab showing in the photo too.

Instead of using a shade guide, your dentist may have an electronic device that they hold against a tooth to take its shade.

The specific method used doesn't necessarily matter as much as the fact that there's consistency. The same method, people involved and room lighting conditions should be the same for both the before and after measurements.


Step #3 - Isolating your teeth.

The peroxide whiteners used with professional whitening systems are caustic in nature and can irritate or even seriously damage soft tissues. Besides just your gums, lips, cheeks and tongue, even your face and eyes are exposed to some risk too.

Dental dams.

As a way of protecting oral tissues, your dentist will "isolate" the teeth being treated by way of placing a "dental dam."

Picture of paint-on dental dam applied around teeth.

A liquid dental dam has been applied around the upper teeth.

Liquid dams.

One type of dam that can be placed involves the use of a gel that's applied on the gum tissue around your teeth. (It's just squirted out of a syringe).
Once the gel has been positioned properly, your dentist will shine their dental "curing" light on it. Doing so activates a catalyst in the gel that causes it to set in just a few moments.
The end result is a barrier that seals around each of your teeth. It prevents the whitener from seeping past and coming into contact with the surrounding gum tissue.

(After treatment, the dam is simply peeled off.)

Rubber dams.

Another form of dental dam is a thin sheet of latex that dentists refer to as a "rubber dam."

Holes are punched in the latex (one for each tooth). It's then slipped into position over the patient's teeth.

The protruding teeth can be treated with the whitener, yet the latex sheet acts as a barrier that prevents it from coming into contact with their gums and lips.

Rubber dams are the traditional way that's used to isolate teeth. Liquid dams are a newer, more convenient technique.


How many teeth will receive treatment?

Just so you don't get any surprises, prior to your bleaching appointment you should ask your dentist specifically which teeth will be whitened.

As a matter of routine, they may be accustom to just bleaching their patient's 6 or 8 front-most teeth on each jaw. Or they may have a policy where they treat every tooth they can access.

You should evaluate your biggest smile in a mirror and determine what's important to you. Then make sure that your dentist has planned accordingly.



Methods used to protect the patient's tissues during treatment.

Animation showing ways teeth are isolated during tooth bleaching treatments.

Paint-on dental dam, cotton rolls and gauze, cheek retractors, face drape.

c) Additional isolation and protection methods.

Besides a dental dam, other isolation materials may be used too. These frequently include:
Cheek retractors - These gently pull your lips and cheeks back out of the way.
Gauze and cotton rolls - These items are tucked under your lips or placed in your mouth for additional retraction and protection.
Face bib - This is simply a paper covering that allows access to your mouth but protects the surrounding portions of your face.

Protective eyewear - It always makes good sense to wear eye protection (glasses) during any type of dental procedure. With this one, tinted glasses are in order if some type of bleaching light will be used (see below).

Takeaways from this section.

Different products seem to have different recommendations in regard to the amount of emphasis placed on establishing the isolation of the working field. We were curious about why.

The hydrogen peroxide concentration found in professional whiteners typically ranges between 15 and 50%.

For comparison purposes, we searched the web looking for the highest concentration hydrogen peroxide bleaching gel sold for use inside bleaching trays (an at-home technique where the whitener frequently comes into contact with oral tissues). We found one that ranged as high as 14%.

This suggests that when lower concentration in-office products are used, the amount of gum irritation expected to be caused by contact with the whitener is fairly minimal. Some type of isolation of the teeth is still important, but less critical.


Picture of tooth whitener that has been applied to the teeth.

The whitener has been applied to the teeth.

Step #4 - Application of the whitener.

At this point, your dentist can apply the bleaching agent.
Professional-grade whiteners are usually a thick paste or gel. It's generously dabbed or painted onto the surface of each of your teeth being treated.

Step #5 - "Activation" of the whitener (optional).

The protocol used with some in-office systems includes "activation" of the whitener via the use of a bleaching light or laser.

Picture of light activation of the tooth whitener.

Some systems recommend "light activation" of the whitener.

The rationale usually given for this step is that light triggers a reaction within the whitener that in turn increases its effectiveness.
This step is controversial.
The need for light activation is not universally accepted by dentists nor universally supported by dental research. We'll also say that:
  • Not all professional systems include this step in their protocol.
  • Some that do consider this step to be optional (hint, hint).
  • There's plenty of dental research that suggests that most systems work equally well with or without the use of a bleaching light.


An in-office bleaching light.

Picture of an in-office bleaching light unit.

These devices look impressive to patients.

It seems that the use of a light unit generally has more to do with impressing patients than it does creating results. If you're interested in this topic you can read about it here: Research evaluating the importance of using bleaching lights.

Step #6 - The whitener is given time to work.

In-office bleaching appointments are usually completed within 60 to 90 minutes, depending on the specific product that's being used.
  • The session may be subdivided into multiple cycles of applying the whitener (2 to 4).
  • If only a single application is made, the whitener is frequently "rejuvenated" during the bleaching process by adding more.



It's possible that you may experience some sensitivity during the treatment process.

Depending on what occurs, your dentist may decide that they need to cut your treatment time short or skip one or more cycles of applying the whitener.

Step #7 - Your bleaching session is wrapped up.

Once your teeth have been exposed to the whitener for the proper amount of time, it will be suctioned off. Your teeth will be thoroughly washed too.

Then the dental dam, and any other isolation materials or devices that have been used, can be removed.

Step #8 - Your dentist will determine the post-bleaching shade of your teeth.

Picture showing a comparison of the whitened and untreated teeth.

A comparison of bleaching results (upper teeth treated / lowers untreated).

Just like before the process was begun, after your bleaching session has been completed your dentist will make another shade evaluation so to see how much whitening has occurred.

Why this isn't really a valid measurement.

You should be aware of the fact that most experts in this field do not consider making a shade-change evaluation immediately after an in-office treatment has been completed to be a valid measurement.

That's because during the whitening process the teeth being treated often become dehydrated (dried out). As this occurs, they lighten up.

That means not all of the lightening effects you see at this point are directly related to the use of the whitener alone.

Why the shade you see probably won't last.

As your teeth rehydrate (this may take just hours or even some days), they will darken slightly.

This dehydration effect is well known to dental researchers and is the reason why studies typically don't make a post-bleaching shade evaluation until at least 2 weeks after the date of their subjects' whitening sessions.

Step #9 - Fluoride treatment (optional).

Your dentist may feel that you should have a professional fluoride treatment after the completion of your whitening session. Here's why:

  • The application of fluoride can help to minimize tooth thermal sensitivity (like that triggered by hot and cold foods and beverages).
  • Some whiteners are mildly acidic and tend to leach mineral content from the surface of teeth. Fluoride can help to promote the remineralization of these areas.


Takeaways from this section.

Compounds other than fluoride can be used for these same purposes.

A common alternative combines potassium nitrate and amorphous calcium phosphate. The potassium nitrate functions as a tooth desensitizer. The calcium phosphate aids with tooth remineralization.

As an alternative to an in-office application, the compound chosen for this step may be given to you for use at home. It may be a gel that's brushed on, or applied by way of wearing plastic trays.


Post-treatment best practices.

Your dentist will probably suggest that you should refrain from consuming staining agents like coffee, colas, tea, red wine or tobacco products (including smoking) for the first two hours after your bleaching session.

Takeaways from this section.

Under normal conditions, a tooth's enamel surface is covered by a thin protective film called the "dental pellicle".

During the bleaching process, this film is removed (polished off). And without the protection it provides, a tooth is at increased risk for staining.

It takes about 2 hours for the pellicle to just naturally reform (it's made up of compounds taken from saliva). That's why chromogenic agents (cola, coffee, etc..) should be avoided during this time period.


Continued treatments using an at-home system (optional).

Your dentist may recommend that your in-office work should be followed up with the use of an at-home product (usually a tray-based one).

Picture of bleaching trays and whitening gel.

Components of a tray whitening kit.

This type of combination treatment is common. And as an explanation as to why it seems fair to say:
  • The use of the at-home system is used to mask the color relapse that frequently occurs after a session due to the dehydration effect mentioned above.
  • In most cases, the professional treatment provides a jump start (quick color change) but it's the continued bleaching with the at-home product that ultimately brings your teeth to their level of "maximum whiteness."
  • (For more details: The rationale associated with combination in-office/at-home treatments.)

If these statements make you wonder why you would choose professional over at-home whitening, then you should read our page that compares the advantages and disadvantages of both methods.


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