The Science Behind Teeth Whitening and How It Really Works

A bright, white smile is more than just a cosmetic goal—it’s often a confidence booster and a reflection of good oral hygiene. But how does teeth whitening actually work? Whether you’ve tried whitening toothpaste or home kits, or are considering a professional treatment, there’s fascinating science behind teeth whitening.

At Newnham Family Dental, we believe that informed patients make the best decisions, so continue reading below to learn what really goes on behind the scenes when you whiten your teeth.

Why Do Teeth Get Stained?

Tooth discolouration is a natural part of life and can be caused by a variety of factors. Stains are typically grouped into two categories:

Extrinsic stains: These occur on the surface of the enamel and are often caused by foods and drinks like coffee, tea, red wine, and berries, or habits like smoking.
Intrinsic stains: These are deeper and located within the tooth structure itself. They can result from aging, certain medications, trauma to the tooth, or excessive fluoride exposure.

Understanding the type of staining is key to selecting the most effective whitening treatment.

The Layers of a Tooth: Enamel and Dentin

Each tooth is made up of multiple layers. The outermost layer, enamel, is semi-translucent and hard, but over time, it can develop tiny pores that trap stains. Beneath the enamel lies the dentin, which is naturally more yellow. As enamel wears down, more of the dentin’s colour shows through, making teeth appear duller or darker.

How Whitening Products Work

Most teeth whitening solutions use peroxide-based agents, such as:

Hydrogen peroxide
Carbamide peroxide (which breaks down into hydrogen peroxide)

These ingredients act as oxidizing agents. When applied to the teeth, they break apart the chemical bonds of colored compounds (called chromogens) in and on the tooth. Once those bonds are broken, the chromogens become smaller, colourless molecules—making the teeth appear whiter.

Different Whitening Methods

There are several ways to apply these whitening agents, and each has its pros and cons:

Whitening toothpaste: Mild abrasives and low levels of peroxide target surface stains.
Strips and gels: Common over-the-counter options that offer moderate results over several days.
Custom trays from a dentist: Offer better fit, safety, and more even whitening.
In-office professional treatments: These use high-concentration peroxide and may include light or laser activation for immediate results.

At Newnham Family Dental, we offer safe, effective whitening options tailored to your needs, with professional supervision for optimal results and minimal sensitivity.

Does Light-Activated Whitening Help?

Some in-office treatments use LED or laser lights to enhance the effects of peroxide. The light itself doesn’t whiten teeth but may help speed up the chemical reaction. While research on the added benefit is mixed, many patients appreciate the faster, more dramatic results when lights are used in conjunction with high-grade whitening gel.

Is Teeth Whitening Safe?

Yes—when performed correctly. Some users experience temporary sensitivity or gum irritation, especially with overuse or improperly fitted trays. That’s why it’s always recommended to consult a dental professional, especially for strong or long-term treatments.

How Long Does Whitening Last?

Whitening results typically last from a few months to up to three years, depending on:

Your diet and lifestyle habits
Oral hygiene routine
Type of whitening method used

Avoiding stain-causing foods, brushing regularly, and using whitening touch-ups can help maintain your results longer.

Trust Your Smile to Newnham Family Dental

Teeth whitening is grounded in solid science and safe practices when done properly. Whether you’re interested in brightening your smile for a special event or just boosting your confidence, understanding how whitening works empowers you to choose the right treatment.

At Newnham Family Dental, we’re here to help you achieve the radiant smile you deserve. Ready to get started? Book an appointment today to explore our professional teeth whitening options and discover what’s possible for your smile.