Does Teeth Whitening Work on Crowns, Fillings, or Bonding? (London Patients Guide)

Many people with existing dental work — such as crowns, fillings, or composite bonding — would like whiter teeth but are unsure how whitening might affect those restorations. It is a very common and reasonable question. The short answer is that whitening gels are designed to work on natural tooth enamel, and they do not change the colour of most dental materials. However, that does not mean whitening is off the table. With the right planning, it is often possible to achieve a brighter, more even smile — even when dental restorations are present.

How Professional Home Teeth Whitening Works on Natural Teeth

Professional home teeth whitening, as offered at a dentist-led whitening clinic, uses custom-fitted trays and a prescription-strength whitening gel. The gel — typically containing hydrogen peroxide at concentrations up to 6%, as permitted by UK law — is applied to the teeth via the trays, usually for a set period each day over one to two weeks.

The active ingredient works by penetrating the natural tooth enamel and breaking down stain molecules within the tooth structure. Over time, this process lightens the intrinsic colour of the teeth, producing a visibly brighter appearance. The results are gradual, controllable, and, when supervised by a dentist, both safe and predictable.

Before beginning any whitening treatment, a dental examination is needed. This allows the dentist to check the health of your teeth and gums, identify any areas of concern, and confirm that whitening is appropriate for you. This step is especially important if you have existing dental work.

Will Teeth Whitening Change the Colour of Crowns or Bridges?

If you have ceramic or porcelain crowns — which are among the most common types of crown used in the UK — whitening gels will generally not alter their colour. These materials are manufactured to a specific shade, and they do not respond to peroxide-based whitening agents in the same way that natural enamel does.

This means that if your natural teeth are whitened successfully, your crowns may begin to look slightly darker by comparison, particularly if they are positioned at the front of your mouth where they are most visible. The crowns themselves have not changed; it is simply the contrast that becomes more noticeable.

In some cases, patients and their dentists may discuss replacing or adjusting visible crowns after whitening to better match the new, lighter shade of the surrounding natural teeth. This is a decision made on an individual basis, taking into account the position, condition, and age of the existing crown, as well as the patient's preferences.

What About Fillings, Inlays and Onlays?

Whitening gels do not usually change the colour of composite (tooth-coloured) or amalgam (silver) fillings, or other restorative materials such as inlays and onlays. These materials, like crowns, are set to a particular shade at the time of placement and do not respond to bleaching agents.

If you have old, stained, or discoloured fillings — particularly those visible in your smile — your dentist may suggest replacing them after whitening so that the new filling material can be matched to your lighter tooth shade. This can help create a more consistent, natural appearance across the smile.

It is important to emphasise that any decision to replace fillings is made individually. Not all fillings need to be replaced after whitening. The dentist will consider clinical need, aesthetics, the size and position of the filling, and how visible it is when you smile. In many cases, back teeth with fillings may not require any change at all.

Can Teeth Whitening Affect Composite Bonding?

Composite bonding — the tooth-coloured resin material used to reshape, repair, or improve the appearance of teeth — does not lighten in the same way as natural enamel. Whitening with composite bonding in place can therefore result in a mismatch between the bonded areas and the surrounding natural tooth, especially if the bonding is on a front tooth.

For this reason, many dentists recommend whitening before bonding rather than afterwards. By lightening the natural teeth first, the composite material can then be colour-matched to the new, brighter shade, resulting in a more seamless finish. You can read more about this approach in our guide on why whitening often comes before composite bonding.

If you already have composite bonding and wish to whiten your teeth, it is still possible. However, you should be aware that the bonded areas may need refinishing, polishing, or replacement to match the lighter shade of the surrounding teeth. Your dentist can advise on whether this is likely to be necessary and what the process involves.

Planning Teeth Whitening When You Already Have Dental Work

When a patient has a combination of natural teeth and dental restorations, careful planning is essential. Dentists typically approach this by carrying out a thorough assessment before recommending a whitening plan.

This assessment usually includes:

• A full clinical examination — checking the health of teeth, gums, and all existing restorations
• Noting the position and visibility of dental work — identifying which restorations are in the smile zone and likely to be affected by a change in tooth shade
• Discussing the treatment sequence — in many cases, it is preferable to whiten first, then replace or update any visible restorations to match the new shade
• Setting realistic expectations — helping patients understand what whitening can and cannot achieve, and what additional treatments may be needed

Sometimes a combination approach is recommended: professional teeth whitening in London followed by replacement of one or two visible fillings or a bonding refresh, for example. This can produce a noticeably improved overall result, even when some dental work is present.

When Whitening May Not Be the First Step

It is worth noting that whitening is a cosmetic treatment, and it should only be carried out on a healthy, stable mouth. There are situations where other dental treatments may need to take priority before whitening is appropriate.

These may include:

• Active tooth decay — any cavities or areas of decay should be treated before whitening gel is applied
• Gum disease — inflamed or bleeding gums should be managed first, as whitening gel on unhealthy gum tissue may cause discomfort
• Failing or damaged restorations — cracked, leaking, or loose fillings, crowns, or bonding may need to be repaired or replaced before whitening
• Significant sensitivity — if you already experience notable tooth sensitivity, your dentist may want to address this before introducing a whitening gel

A professional dental hygiene appointment before whitening can also help remove surface staining and tartar, ensuring the whitening gel can work effectively on clean, healthy tooth surfaces.

Questions to Ask Your Dentist Before You Whiten

If you have crowns, fillings, or bonding and are considering whitening, it helps to go into the consultation prepared. Here are some useful questions you might ask:

• "Will my crowns, fillings, or bonding match after whitening?" — This helps you understand whether any visible restorations may need updating afterwards.
• "Will I need to replace any front fillings after whitening?" — Your dentist can advise on whether this is likely, based on the position and condition of your current fillings.
• "In what order would you recommend treatment?" — Understanding the planned sequence of treatments helps you prepare for the process and manage expectations.
• "How long should I wait between whitening and having restorations replaced?" — There is usually a recommended settling period after whitening before matching new restorations.

Open discussion with your dentist helps avoid surprises and ensures that you are comfortable with each step of the process. Remember, there is no pressure to proceed — cosmetic treatments should always be a considered, personal choice.

Next Steps if You Have Crowns, Fillings or Bonding and Want Whiter Teeth

If you have existing dental work and would like to explore whitening, the most important first step is a dental assessment. Every mouth is different, and the best plan will depend on the type, position, and condition of your restorations, as well as the current shade and health of your natural teeth.

During a consultation, your dentist can review your specific situation, discuss what whitening can realistically achieve, and outline whether any follow-up treatments — such as replacing visible fillings or refreshing bonding — might be beneficial. An individual plan can then be made, which may include whitening, new restorations, or both.

If you would like to take the next step, contact us to book a teeth whitening consultation in London. Our team can help you understand your options and create a personalised plan for a brighter, more confident smile.

Disclaimer: This article provides general information only and does not constitute personalised medical advice. Individual results vary depending on the condition of the teeth, type of restorations, and other factors. Always consult a GDC-registered dentist before beginning any whitening treatment.