Teeth whitening

Since time immemorial, humans have been looking for different ways to whiten their teeth. The ancient Egyptians used pumice powder, crushed eggshells and wine vinegar for this. In the Middle Ages, teeth were whitened by filing them with metal files and applying nitric acid. This made the teeth whiter, but also left them irreversibly damaged. Modern technologies offer teeth whitening without any harmful side effects on the tooth structures.

Hydrogen peroxide was first used for whitening teeth in 1884. Due to its low molecular weight, it penetrates through the enamel into the dentine without damaging the tooth tissues. Since then, hydrogen peroxide has been considered the most effective bleaching agent. Since pigmented substances penetrate into the deeper layers of the enamel and dentine, efforts were made to increase the absorption and penetration of hydrogen peroxide. In 1918, Dr Wallace Abbott was the first to use high-intensity light to speed up the whitening process, paving the way for in-office whitening treatment.

Teeth whitening is an oxidation-reduction process, where oxidising substances – free radicals with unpaired, easily reducible electrons – easily penetrate into the bleaching material. As the oxidising agent when whitening teeth, we use hydrogen peroxide, which breaks down into two free radicals: HO₂ (hydroperoxyl) and O2 (oxygen). These radicals are very active, so they move freely between the microscopic strands of the tooth enamel and penetrate into the dentine, breaking down macromolecular pigment compounds into smaller and less reflective ones.

Organic substances on the surface of the teeth (dental plaque) interfere with the oxidation reaction, and enzymes change this reaction by significantly reducing the amount of free radicals, which results in less and slower whitening of the teeth. So in order to achieve the best teeth whitening outcome, it should only be done on clean teeth. Therefore, the first step should be a professional teeth cleaning, after which the natural colour of the tooth will be visible. This allows for an accurate assessment of the colour, which will make it easy to choose the most suitable teeth whitening method.

In the tooth whitening process, the so-called “saturation point” is very important, as this is when the teeth no longer get any whiter because all of the pigment compounds are broken down. After this, the organic structures of tooth enamel and dentine begin to break down. This can happen when teeth are whitened without a dentist’s consultation or without following the dentist’s recommendations regarding the duration of whitening and materials, as well as when teeth are whitened excessively, with too strong a concentration, or with substances purchased without the dentist’s knowledge. If you are having your teeth whitened and they are no longer getting any whiter, this indicates that the point of saturation has been reached and the whitening treatment should be stopped.

Be sure to consult our dentist before having your teeth whitened. During the consultation, we will determine the reasons for the discolouration of your teeth as well as what method is best for you, i.e. teeth whitening or another dental procedure.

We will also evaluate your teeth according to the aesthetic smile criteria during the consultation. For example, how many teeth are visible when you smile and whether you have any aesthetic gum defects (unevenness of the gum line, too much gum showing when you smile, etc.). Teeth whitening makes defects like these more noticeable, so additional corrective procedures may be needed to create an attractive smile.

After evaluating your smile, we will determine whether the surfaces of the teeth to be whitened are not damaged by caries. In this case, the spaces between the teeth may be darker, making the teeth look less white. Teeth may also appear darker due to dark restorations or old fillings. Since composite fillings or ceramic crowns cannot be whitened, and dark restorations in the area of the teeth being whitened give them a darker shade, they may need to be replaced after the teeth whitening so that the fillings match the whiter teeth.

If your dental cervices or your tooth roots are exposed, your teeth may be sensitive during whitening. You should therefore opt for in-office whitening, where we can cover your dental cervices with protective material before the procedure. Tooth sensitivity during whitening can be caused by old, permeable restorations as well. It is also important to note that the roots of the teeth whiten more slowly than the crowns, so if the dental cervices are exposed, the teeth near them may remain darker. If you have white spots or fluorosis on your teeth, you should keep in mind that they will not whiten. Immediately after whitening, these spots may seem even more prominent, but once the teeth get lighter, they will be less noticeable.

Each individual case is different, so a consultation before whitening is necessary.

During the consultation, you will find out:

• Which whitening method is the best fit, taking into account the condition of your teeth and your expectations, budget and lifestyle.
• Whether other dental procedures are necessary before teeth whitening to avoid possible tooth sensitivity or poor whitening results.
• Whether you will need other dental procedures after teeth whitening so you can enjoy the smile you are looking for.
• The estimated level of whiteness you can expect after the procedure.

Clinical trials have not proven that whitening is safe during pregnancy or while breastfeeding, so we do not recommend it in that case. We also do not recommend teeth whitening if you are under the age of 18, as there are not enough clinical trials to reliably determine the safety of this procedure in younger patients.

If your gums cover too much of your tooth surface (otherwise known as a gummy smile), your teeth look short. Having them whitened will only make this more pronounced. Whitening also makes any unevenness in the gum line more visible, so we recommend having gum grafting done before teeth whitening.

In some cases, periodontal or endodontic treatment may be more necessary than teeth whitening. These cases include trauma to the teeth, which can cause the tooth to become darker, regardless of whether the pulp has remained viable or not. If your individual teeth are darker due to endodontic treatment, then we recommend additional internal tooth whitening.

If you want a quick and optimal result, we suggest you try the Zoom!® whitening system. This is a safe and effective procedure that takes an hour and a half. After protecting the gums with a special material, we put a 6% hydrogen peroxide whitening formula on the teeth, which is then activated in four 15-minute cycles with a visible, 404-500 nm blue light.

The pH of the bleaching agent is alkaline. The alkaline medium increases the chemical reaction of the decomposition of hydrogen peroxide, so whitening happens faster, producing a visible difference in a relatively short time and without damaging the tooth enamel.

The main advantage of the Zoom!® system is that it is also suitable for clinical situations where other teeth whitening methods may be less effective, such as for dark enamel stains caused by smoking or heavy coffee consumption, tetracycline-stained teeth, or when the transparent edge of the enamel is very pronounced and as a result the teeth acquire a greyish shade.

In which cases is the Zoom!® whitening system the best choice?

• When you want noticeable results in a single 90-minute session. Achieving the same result will take 10-14 days with teeth whitening trays, or two days with laser teeth whitening.
• When your teeth are a darker shade and have pigment spots caused by smoking or heavy coffee consumption. A single Zoom!® session can lighten your smile by 5-8 shades according to the VITA Shade Guide.
• With tetracycline-stained teeth, it may take up to six months to remove their uneven greyish shade with teeth whitening trays. Meanwhile, laser teeth whitening might not give you the result you are looking for.
• When you have dental fluorosis and want to even out the colour of your teeth. Dental fluorosis gives the enamel white spots and an uneven white colour – some areas of the tooth are significantly whiter than others. To even out the colour, the dark spots have to undergo significant whitening, and the Zoom!® system is best for that.
• If you want to mask the transparent biting edge of the enamel of the front teeth, which is grey and makes the teeth appear greyer due to the wider area of transparency. The Zoom!® whitening agent is enriched with minerals that penetrate into the deeper layers of the enamel together with the whitening components, masking colour unevenness.

If you decide to use teeth whitening trays, we will take your dental impressions during the first appointment. Using the impressions, we then custom make your teeth whitening trays and fill them with 10-16% carbamide peroxide. This is hydrogen peroxide broken down into urea crystals. Due to the longer exposure time, carbamide peroxide whitens teeth more slowly than pure hydrogen peroxide. 1% hydrogen peroxide is equivalent to 2.765% carbamide peroxide. Because of these properties, carbamide peroxide is the most commonly used active ingredient for teeth whitening trays.

On average, the trays are worn with the whitening agent two to four hours per day or overnight. The standard teeth whitening tray cycle lasts 10 days.

Laser teeth whitening is one of the most advanced, effective and safest methods of teeth whitening. The monochromatic properties of the laser and the specially formulated gel make it possible to whiten teeth safely, quickly and effectively in one or several visits.

Using the VITA Shade Guide, we determine the colour of the teeth before whitening. In order to prevent hydrogen peroxide from getting on the gums during the procedure, we cover them with a special protective material. We also cover the surfaces of the teeth with it if the dental cervices are exposed or enamel erosion is visible. For laser teeth whitening, we apply 25-45% hydrogen peroxide, which we then activate with a laser. Its rays accelerate the chemical oxidation reaction and whiten teeth faster.

LaserSmile™ (Biolase, USA) uses one of the most advanced teeth whitening technologies, TCIA™ (Target Chromophore In-Phase Accelerated-Activation). With LaserSmile™, laser energy is absorbed by special particles in the whitening gel to accelerate decomposition of the 38% hydrogen peroxide into free radicals, resulting in shorter treatment time. In addition, the whitening agent is only in contact with the tooth for 16-32 minutes, so the risk of damaging the dental tissues is greatly reduced. Laser whitening is also safe because no heat is released when the whitening agent is activated by the laser, so the teeth are less sensitive and the risk of damaging the dental pulp is reduced.

The success and outcome of teeth whitening depends on the ability of the whitening agent to penetrate the pigment substances, which are absorbed into the dental tissues and remain there long enough to oxidise the pigment-containing molecules. During whitening, the surface of the tooth dries out a little, so avoid dark, staining food and drinks after the procedure, or at least use a straw. After achieving optimal teeth whiteness, you should repeat the process every six months with teeth whitening trays or every 12-18 months with laser teeth whitening to maintain your results.