Is Teeth Bleaching Safe? Understanding the Risks and Benefits

In this highly visual social-media age, the appeal of a bright smile is more sought-after than ever. In the UK and around the world, more people than ever are seeking whiter teeth to boost their confidence and freshen their look. Naturally, teeth whitening has become one of the most sought-after cosmetic dental treatments today.

Whether you’ve considered a whitening toothpaste, booked a professional bleaching session, or been tempted by an at-home kit, you’ve probably come across the terms “teeth whitening” and “teeth bleaching”, often used interchangeably. But is there a difference? And, more importantly, are these treatments safe?

This article explores everything you need to know about safe teeth whitening in the UK. We’ll break down the differences between whitening and bleaching, compare treatment options and discuss the potential risks so that you can make an informed, confident choice if you want to whiten your teeth.

Whitening vs Bleaching: Is There a Difference?

Let’s clear something up: although “teeth whitening” and “teeth bleaching” are often used interchangeably (especially in marketing), they’re not quite the same.

Teeth whitening generally refers to removing extrinsic stains − those on the outer surface of your teeth − caused by things like poor oral hygiene, coffee, tea, red wine, smoking and so on. These whitening products may contain mild abrasives or very low concentrations of bleaching agents. The aim is simply to restore your teeth to their natural shade.

Teeth bleaching, on the other hand, goes deeper. It uses peroxide-based chemicals, such as hydrogen peroxide or carbamide peroxide, to change the intrinsic (internal) colour of the tooth enamel. This process can make teeth several shades lighter than their original colour. It’s especially useful for teeth that have darkened due to ageing, injury or certain medications.

To be clear: dental bleaching products don’t contain chlorine bleach. They’re not household cleaning agents − they’re professional, dental-grade formulations designed to be used with care.

Teeth Whitening Treatment Options

If you’re considering teeth whitening in the UK, there are two broad categories: professional treatments (overseen by a dental professional) and over-the-counter (OTC) options.

Professional Teeth Whitening

Performed or prescribed by dentists, professional treatments are not only more effective − they're also safer. Under professional supervision, peroxide concentrations between 15%–43% can be used safely and effectively.

There are two main types:

Dentist-supervised home whitening: Your dentist takes impressions of your teeth to create custom-fitted trays. They then provide a gel containing carbamide or hydrogen peroxide, along with detailed instructions. Typically, you’ll apply the gel at home for 30–45 minutes a day, or wear the trays overnight, over a few weeks. This method delivers gradual, natural-looking results under safe supervision.

In-surgery whitening (including laser whitening): This involves a higher concentration of bleaching gel applied in the clinic, often activated by a special light or laser. It’s popular for delivering faster, more dramatic results − sometimes in as little as an hour. Some systems may still include take-home trays for continued care. While more costly, the immediate results and close monitoring make this the preferred choice for many.

Over-the-Counter Whitening Products

Teeth whitening products include strips, brush-on gels, rinses and whitening toothpastes. However, UK and EU regulations limit hydrogen peroxide content in OTC products to 0.1%, which is too low for any significant bleaching effect. At best, they may lift minor surface stains, but they won’t whiten the internal tooth structure.

DIY home kits (often featuring boil-and-bite trays) are also widely available, but they can be risky. Poorly fitting trays may allow the gel to leak, leading to gum irritation or burns. Some kits − especially those sold online from unregulated sources − may contain illegal and dangerous peroxide levels.

‘Natural’ methods − like baking soda, charcoal, or oil pulling − are also popular, but many are too abrasive or their so-called benefits remain unproven. Long-term use can damage enamel and won’t deliver true bleaching results.

Who Can Safely and Legally Perform Teeth Whitening in the UK?

Fact: Teeth whitening isn’t just a beauty treatment, it’s a dental procedure. That means it falls under strict regulation in the UK.

Only registered dentists and certain regulated dental professionals (like dental hygienists or therapists) can legally perform or supervise teeth whitening procedures. Hygienists and therapists may carry out the treatment, but only under a dentist’s prescription.

Check the General Dental Council Register

Before undergoing treatment, always check whether your provider is registered with the General Dental Council (GDC). You can search online using their public register. If they’re not listed, they’re not legally allowed to carry out whitening.

The Dangers of Illegal Providers

Unfortunately, some beauty salons and unqualified individuals offer teeth whitening services. This is illegal under the Dentists Act 1984. This isn’t just a legal issue. It’s a safety concern.

These providers often:

• Use unregulated or unsafe products, with peroxide levels far beyond the legal limits (some cases involved over 300 times the permitted concentration).
• Lack the training to identify underlying dental issues, like decay or gum disease, which could worsen with whitening.
• Fit improper trays or apply gels incorrectly, causing chemical burns, severe sensitivity, and permanent damage to enamel or gums.

If you’re offered teeth whitening by someone without dental qualifications, just say “no”. You can also report illegal activity to the GDC.

Understanding the Potential Risks and Side Effects

When performed by a qualified dental professional, teeth bleaching is generally safe. But like any treatment, there are potential risks − especially if used improperly or carried out by untrained individuals.

Common (Usually Temporary) Side Effects

• Tooth sensitivity: Bleaching agents can make teeth temporarily more sensitive to temperature or pressure. This is usually short-lived and manageable. Dentists often recommend desensitising toothpaste or adjusting treatment strength or frequency.
• Gum irritation: If bleaching gel contacts the gums − especially if the tray fit is poor − it can cause irritation or even a chemical burn. This is more likely with OTC or illegal kits and can result in soreness or whitening of the soft tissues (blanching).

More Serious Risks (Usually from Overuse or Illegal Kits)

• Tooth enamel damage: Excessive use of strong, unregulated products can erode the enamel. Once damaged, enamel doesn’t grow back. This increases sensitivity, decay risk, and may leave a chalky, unnatural appearance sometimes referred to as “bleachaholism.”
• Tooth pulp or nerve damage: In rare cases, bleaching can cause permanent nerve damage, especially if strong peroxide reaches inside the tooth, or if the tooth already has hidden damage.
• Uneven whitening: Whitening doesn’t affect crowns, fillings, veneers, or dentures. If you have dental restorations, they’ll remain the same shade, potentially resulting in an uneven smile. Similarly, whitening teeth with fixed braces can leave darker patches where brackets were.

Other issues can include digestive discomfort (if the gel is accidentally swallowed) or allergic reactions to ingredients, though both are rare.

The bottom line? Professional oversight matters. It reduces the likelihood of side effects and ensures the best, safest outcome for your smile.

Is Teeth Whitening Right for You?

Not everyone is an ideal candidate for whitening, which is why a thorough dental check-up is essential first. Things to consider include:

Your Oral Health

Conditions like tooth decay, gum disease, or cracked teeth must be treated before whitening. Otherwise, bleaching can cause significant pain or make existing problems worse.

The Type of Stains

Whitening is most effective for intrinsic stains (caused by age, trauma or medication). Extrinsic stains from food or smoking may only need cleaning or mild whitening.

Existing Dental Work

As mentioned, restorations won’t bleach. Be prepared to replace fillings or veneers to match your new tooth colour, if needed.

Your Natural Tooth Colour

Yellow-toned teeth usually respond well to whitening. Brown or grey-toned teeth may not lighten as predictably.

Talk to your dentist. They can help assess whether whitening will work for you and create a personalised plan.

Final Thoughts

Teeth whitening can be a safe and transformative treatment − when done properly. In the UK, the safest approach is always to go through a qualified dental professional who can assess your suitability, monitor the process and use clinically approved products. While over-the-counter products or beauty salon deals may look appealing, these short-cuts often come at a cost. The risk simply isn’t worth it. 

Considering teeth whitening? Perhaps for your wedding or after having had Invisalign treatment? At Hampstead Orthodontic Practice, we’re happy to talk through your options and help you achieve a whiter, healthier smile − safely and professionally. Get in touch.