The Science Behind Professional Teeth Whitening Treatment: How It Works

Professional teeth whitening treatments have been gaining immense popularity in recent years due to their effective and long-lasting results. But have you ever wondered how these treatments work?  The science behind teeth whitening solutions revolves around the chemical process of bleaching. Teeth whitening treatments aim to remove stains and discolouration from the enamel and dentin of the teeth, resulting in a brighter, whiter smile. Let’s break down the science behind the process:

The Structure of a Tooth

 To understand teeth whitening, it’s important to know the basic structure of a tooth. The outermost layer is called the enamel, which is a hard and mineralised substance protecting the underlying dentin. The dentin, located beneath the enamel, contains microscopic tubules that lead to the tooth’s inner pulp.

Teeth Staining and Discolouration

 Teeth can develop two types of stains, extrinsic and intrinsic. Extrinsic stains occur on the surface of the teeth (the enamel) and are caused by external factors like food and drink (coffee, tea, red wine and some curries for example), tobacco use, and poor oral hygiene. On the other hand, intrinsic stains occur within the tooth structure and are often caused by factors such as ageing, dental trauma, particular medications or excessive fluoride exposure during tooth development. 

Both extrinsic and intrinsic stains are responsible for the discolouration of teeth and the reason why so many people are now turning to professional teeth whitening treatment to enhance their smile.

Bleaching Agents

 The primary components used in teeth whitening treatments are bleaching agents, typically hydrogen peroxide (H2O2) or carbamide peroxide.

Hydrogen peroxide is a powerful bleaching agent used in many professional teeth whitening treatments. It is highly effective at breaking down stains. When applied to the teeth, hydrogen peroxide penetrates the enamel and reaches the dentin, which is responsible for the tooth’s overall colour.

Carbamide peroxide is another commonly used bleaching agent in professional teeth whitening treatments. It is a derivative of hydrogen peroxide and works in a similar way, albeit much slower.  Carbamide peroxide breaks down into hydrogen peroxide when applied to the teeth. The hydrogen peroxide then undergoes the same process of breaking down the pigmented molecules to reduce or remove the staining to achieve a whiter smile.

Oxidation Process

 The bleaching agents used in teeth whitening treatments are oxidising agents, meaning, they release oxygen molecules. When the bleaching agent comes into contact with the teeth, it penetrates the enamel and dentin, where it then breaks down the larger stain molecules into smaller, less pigmented ones. This process involves the release of oxygen ions that react with the chromogens (colour-producing compounds) in the stains, effectively oxidising and reducing their concentration.

Peroxide Penetration

 The bleaching agents need to penetrate the enamel to reach the dentin where intrinsic stains reside. Hydrogen peroxide or carbamide peroxide molecules are small enough to penetrate the enamel and enter the dentin. Once in the dentin, they continue the oxidation process, targeting and breaking down the molecules responsible for intrinsic stains.


 In some cases, teeth whitening treatments are activated by light or heat. Light-activated or laser-assisted whitening techniques use a specialised light source to activate and accelerate the bleaching process. The light or heat helps initiate the breakdown of the peroxide molecules, leading to faster and more efficient stain removal.

Tooth Sensitivity

 Teeth whitening treatments can cause temporary tooth sensitivity for some patients. This sensitivity occurs because the bleaching agents can temporarily open the tubules in the dentin, exposing the nerves to external stimuli. However, the good news is that the sensitivity usually subsides shortly after the treatment, and desensitising agents can be used to minimise discomfort during and after the procedure. We have a separate blog on how to deal with sensitivity after teeth whitening here.


 After the professional teeth whitening treatment, it is important to follow the instructions provided by your orthodontist (or dentist). This typically includes avoiding certain foods and drinks that can stain the teeth, practicing good oral hygiene and attending regular dental check-ups. Following these instructions will help prolong the results of your dental whitening treatment.

Professional teeth whitening treatments harness the power of hydrogen or carbamide peroxide to effectively remove and lighten tooth stains. By breaking down pigmented molecules within the enamel and dentin, these treatments can achieve noticeable whitening results. However, it is crucial to undergo professional teeth whitening under the guidance of a dental professional to ensure safety and optimal results. With the science behind professional teeth whitening demystified, you can make informed decisions to achieve a brighter, whiter and more confident smile.

Here at Orthodontics For You, we offer polanight teeth whitening to patients of our Solihull and Bromsgrove practices once their teeth straightening treatment is complete. That said, even if we haven’t fitted you with a brace, we can still offer the same teeth whitening treatment. We’ll start with an initial assessment to see if our polanight teeth whitening will work for you (most people we treat are suitable). You will have custom made trays created especially for your teeth (similar to a mouth guard) which will have specific reservoirs for each tooth. This allows even distribution of the bleaching gel while preventing any irritation to your gums. The trays are worn whilst you sleep and it can take 5 to 14 days to lift your teeth to the desired shade, which means you’ll have a pearly white smile in no time!

The gel we use at Orthodontics For You as part of your teeth whitening journey is a tasty spearmint flavour – it’s both fresh and long-lasting! The bleaching gel also has a unique blend of soothers, conditioners and high water content to assist in reducing sensitivity. Throughout treatment, the formation of plaque and tooth decay is also significantly reduced.  

Polanight teeth whitening treatment at Orthodontics For You is a safe and simple way to whiten your teeth (remember, teeth whitening should only ever be administered by a dental professional).  Click here to book a consultation and start your journey to a beaming white smile! Or if price is on your mind, take a look at our finance page. Here you’ll find a price list of our full service range, including orthodontic braces and teeth whitening solutions.


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