Teeth Whitening London: Common Questions Patients Ask Before Booking

If you are considering professional teeth whitening in London, you probably have questions. That is entirely normal — most patients do. From safety and sensitivity to costs and what kind of results to expect, the questions below are among the most common we hear. The answers here are general and intended to help you feel more informed before you book. Personal advice, of course, comes from an individual examination with a GDC-registered dentist.

Is Professional Teeth Whitening Safe for My Teeth and Gums?

When carried out under the supervision of a GDC-registered dentist, professional teeth whitening is widely regarded as a safe cosmetic treatment. In the UK, dentists can legally prescribe whitening gels containing up to 6% hydrogen peroxide — a concentration that is effective for lightening tooth colour while remaining within established safety guidelines.

Before any whitening treatment begins, the dentist will carry out a thorough examination. This includes checking for tooth decay, gum disease, cracks, worn enamel, and any other conditions that could affect your suitability or comfort during treatment. If any issues are identified, these are typically addressed before whitening proceeds.

It is worth noting that whitening products sold directly to consumers in shops or online are limited to just 0.1% hydrogen peroxide under UK regulations — a fraction of the strength available through a dental practice. Treatments offered by non-dental professionals, such as beauty salons, are illegal in the UK and carry additional risks.

How Does Dentist-Led Home Whitening with Custom Trays Work?

Home teeth whitening with custom trays in London follows a structured, supervised process. It is quite different from generic shop-bought kits, which use one-size-fits-all trays and much weaker gels.

The typical steps are:

• Consultation and examination — the dentist assesses your oral health, discusses your goals, and confirms whether whitening is appropriate
• Impressions — precise moulds are taken of your teeth to create custom-fitted whitening trays
• Tray fitting — the trays are checked for comfort and accurate fit, ensuring even gel distribution and protection for the gums
• At-home gel application — you wear the trays with a prescription-strength gel at home for a set period each day, typically over one to three weeks
• Review — the dentist reviews your progress and can adjust the plan if needed

The custom trays are a key part of the process. Because they are made from impressions of your own teeth, they hold the gel in close contact with the enamel and help prevent it from leaking onto the gums. For a full guide to home vs laser teeth whitening, our comparison page explains the key differences between the two approaches.

How White Will My Teeth Go — and Will They Look Natural?

This is one of the most frequently asked professional teeth whitening questions, and the honest answer is that results vary. Factors that influence the outcome include your natural tooth shade, the type and depth of any staining, how consistently you wear the trays, and how your enamel responds to the gel.

Most patients aim for a brighter, fresher-looking smile rather than an extremely white or artificial appearance. A good dentist will discuss realistic expectations during the consultation and help you understand what is achievable for your particular teeth. It is not possible to guarantee a specific shade result for every patient, as individual variation is significant.

The goal is typically an improvement that looks natural and enhances your confidence — not a dramatic transformation that draws attention for the wrong reasons.

Will Teeth Whitening Make My Teeth More Sensitive?

Some patients experience temporary sensitivity during or shortly after whitening. This is a recognised possibility and is usually mild, presenting as a brief, sharp sensation when consuming hot or cold items. In most cases, it settles within a few days of completing or pausing treatment.

Dentists can take several steps to help manage sensitivity:

• Adjusting the concentration of the whitening gel
• Reducing the daily wear time of the trays
• Recommending alternate-day use rather than daily application
• Suggesting a toothpaste formulated for sensitive teeth before and during treatment

If you already have sensitive teeth, whitening may still be possible, but it requires careful assessment and a tailored approach. For questions specific to whitening with sensitive teeth, our dedicated page goes into further detail.

How Long Do Teeth Whitening Results Usually Last?

The longevity of whitening results depends on several factors, and it is not possible to give a single definitive answer. For many patients, results can last from several months to a year or more, but this varies depending on:

• Diet — regular consumption of staining foods and drinks such as coffee, tea, red wine, and certain sauces can gradually reintroduce discolouration
• Smoking — tobacco use is one of the most significant causes of tooth staining and can shorten the lifespan of whitening results
• Oral hygiene — thorough daily brushing and flossing, combined with regular professional cleaning, helps maintain a brighter appearance for longer

Some patients choose to use occasional top-up whitening sessions under dental guidance, using their existing custom trays with fresh gel. This can be a cost-effective way to refresh results over time.

Will Whitening Work If I Have Fillings, Crowns or Bonding?

Whitening gels are designed to work on natural tooth enamel. They do not typically change the colour of dental restorations such as composite fillings, porcelain crowns, bridges, or bonding material. This means that if your natural teeth are lightened, existing restorations may appear darker by comparison.

In these situations, the dentist may discuss the option of replacing or updating visible restorations after whitening, so that the new material can be shade-matched to your lighter teeth. This is assessed on a case-by-case basis, depending on the position, condition, and visibility of the restoration.

Whitening is generally carried out first, with any restorative adjustments planned afterwards. This ensures that the final shade of all visible tooth surfaces — natural and restored — is as consistent as possible.

Can I Whiten My Teeth If I Have Gum Disease or Other Dental Problems?

Active gum disease, untreated tooth decay, significant enamel erosion, or other oral health problems usually need to be addressed before whitening can safely begin. Applying whitening gel to compromised teeth or inflamed gums could cause unnecessary discomfort and may not produce good results.

This is one of the reasons why a dental examination is an essential first step. The dentist can identify any issues, recommend appropriate treatment, and then reassess whether whitening is suitable once the mouth is healthy and stable. Whitening should always be seen as part of a broader healthy-mouth plan, not as a substitute for necessary dental care.

How Much Does Professional Teeth Whitening Cost in London?

The cost of professional teeth whitening in London varies between practices and depends on what is included in the package. Some clinics include the initial assessment, custom trays, a full course of gel, and follow-up reviews within a single fee, while others may charge for elements separately.

When comparing prices, it is worth considering the full scope of what is offered, including the quality of the trays, the strength and brand of gel, and the level of ongoing dental support. For answers about teeth whitening costs in London, our pricing page provides a clearer picture of what is typically included.

As with any healthcare treatment, the cheapest option is not always the most appropriate. Choosing a CQC-registered dental practice with GDC-registered professionals ensures that your treatment meets UK regulatory standards.

How Do I Know If Teeth Whitening Is Right for Me?

The best way to find out whether whitening is suitable for you is to book a consultation with a dentist. During this appointment, the dentist can:

• Examine your teeth and gums
• Discuss your goals and expectations
• Explain the likely outcomes based on your individual situation
• Outline any treatments that may need to come first
• Answer any remaining questions you have

This is a shared decision-making process. The dentist provides the clinical information and professional perspective; you decide whether whitening feels right for you based on that advice. There is no obligation to proceed after a consultation — it is simply an opportunity to gather the information you need to make an informed choice.

If you are interested in finding teeth whitening near you in London, our location page can help you explore options in your area.

What Is the Next Step If I Want to Go Ahead?

If you decide that whitening is something you would like to explore, the typical pathway is straightforward:

1. Consultation — your dentist examines your teeth and discusses your suitability and goals
2. Consent — you are given clear information about the treatment, its benefits and limitations, and you provide informed consent before anything begins
3. Impressions — moulds of your teeth are taken to create your custom whitening trays
4. Tray fitting and gel provision — the trays are checked for fit and comfort, and you are provided with your prescription whitening gel along with detailed instructions
5. At-home whitening — you carry out the whitening at home, following the agreed schedule
6. Review — the dentist reviews your results and discusses any further steps, such as top-up gel or restorative adjustments

If you feel ready to take the first step, or if you simply have more questions, contact us to book a teeth whitening consultation in London. Our team is happy to help you understand your options at your own pace.

Disclaimer: This article provides general information only and does not constitute personalised medical advice. Individual suitability, results, and experiences vary. Always consult a GDC-registered dentist before beginning any whitening treatment.