Do Crowns and Fillings Whiten? Shade Matching

Short answer

No, crowns and fillings do not whiten. Porcelain and zirconia crowns, veneers, composite fillings, bonding and implant crowns do not change colour with whitening gel; the gel only acts on colour molecules in natural tooth tissue. So whitening is usually done first, then there is a wait of about 2 weeks once the colour has settled, and visible restorations are replaced to match the new shade.

Why don't crowns and fillings whiten?

Crowns and fillings do not whiten because the structure that whitening gel acts on is not present in these materials. Hydrogen peroxide breaks down organic colour molecules within enamel and dentine by oxidation, and this is how the colour lightens.

Porcelain, zirconia, glass ceramic and composite resin, on the other hand, are materials whose colour is set during manufacture. The gel stays on the surface of these materials but does not change their internal colour. We explain how the active ingredient works in detail on our hydrogen peroxide and carbamide peroxide page.

Tea, coffee or tobacco stains on the surface of a restoration can be removed to some extent with professional cleaning and polishing. However, this does not lighten the material's own colour; it only removes surface build-up.

Which restorations are not affected by whitening?

None of the artificial materials in the mouth truly lighten with whitening. The table below summarises the most common restorations and the points to bear in mind.

Restoration	Does it lighten?	Note
Porcelain or zirconia crown	No	Usually needs replacing to match the new shade.
Porcelain veneer	No	If veneers are planned, whitening is done beforehand.
Composite filling	No	Colour difference may become noticeable on front teeth; it can be replaced.
Bonding and composite veneer	No	Polishing reduces surface stains; the colour does not change.
Implant crown	No	When neighbouring teeth lighten, the crown may stay darker.
Temporary crown	No	The permanent restoration shade is chosen after whitening.

Why does a colour difference appear after whitening?

A colour difference arises because natural teeth lighten while restorations stay the same shade. A filling that matched your teeth before whitening may look darker or more yellow afterwards.

This difference is most noticeable on the front teeth, in the area that shows when you smile. Fillings on back teeth are usually not visible, so they often cause no problem.

Staining can also develop over time along the edges of old composite fillings. After whitening, these edge lines may become more obvious. This is discussed in advance at the examination and expectations are set accordingly.

How much a colour difference stands out depends on the size and position of the filling, your smile line and how much the teeth will lighten. Small fillings at the back can often be left as they are. On the front teeth, however, composites between two teeth or on the biting edge are usually at the top of the replacement list. This assessment is made from photographs and a shade record before whitening begins.

How is shade matching planned?

The right order for shade matching is: whitening first, then a wait, and restoration replacement last. A typical plan consists of these steps:

Examination: Existing fillings, crowns and veneers are assessed; any decay or gum problems are treated first.
Shade record: Your starting shade is measured with a shade guide and photographed.
Whitening: In-office, take-home or combined whitening is carried out.
Waiting: There is usually a wait of about 2 weeks until the colour settles.
Replacing restorations: Visible fillings, crowns or veneers are remade to match the new, settled shade.

This sequence means the restoration shade is chosen only once, to match the new colour. This removes the need to replace the same filling twice.

Measuring tooth colour with a shade guide when planning filling shade matching before whitening — Your starting shade is recorded; the restoration shade is chosen after whitening. · Illustrative AI-generated image; not a patient.

Why wait about 2 weeks before replacing restorations?

There are two main reasons for waiting: to let the colour stabilise and to let bonding strength recover. The waiting time is usually about 2 weeks, but it can vary from person to person.

The colour stabilises: During whitening the teeth lose some water and look whiter than they really are. As they rehydrate, the colour comes back slightly and settles within a few days.
Bonding strength recovers: After treatment, oxygen residues remain in the tooth structure for a while. These residues can temporarily weaken the bond of composites and adhesives.
Sensitivity passes: If you have sensitivity after whitening, the teeth are given time to settle before restorative work.

Practical note

Avoiding dark-coloured drinks and foods during the waiting period helps the colour settle more evenly.

What can be done if you have crowns or veneers on your front teeth?

If you have crowns or veneers on your front teeth, the options depend on the colour and condition of the restoration. Your dentist will assess the right approach with you at the examination.

If the restoration is lighter: The natural teeth can be whitened to bring them closer to the restoration's shade. In this case the crown may not need replacing.
If the restoration is darker: After whitening, the crown or veneer can be replaced to match the new shade.
If new veneers are planned: Whitening is done first and the porcelain veneer shade is chosen to match the whitened teeth.
If you do not want any changes: The crown is left as it is; whitening is planned so as not to create a colour difference, or not done at all.

Porcelain veneers on the front teeth matched in shade with whitened natural teeth — If veneers are planned, whitening is done first. · Illustrative AI-generated image; not a patient.

Does a root-filled or single darkened tooth whiten?

A root-filled tooth that has darkened over time often responds only partly to external whitening. Because the discolouration in these teeth comes from inside, a different method is needed.

In the method called internal bleaching, the whitening agent is placed inside the tooth, above the root filling. You can find the details on our whitening a root-filled tooth page. If the tooth has a crown, this method cannot be used; shade matching is achieved by replacing the crown.

Does whitening damage existing fillings?

Whitening carried out at the right concentration and under dental supervision generally causes no significant damage to sound restorations. Ceramic materials are hardly affected by peroxide; slight roughening may occur on composite surfaces, and this can be removed by polishing.

Fillings with open margins, leaks or decay underneath, however, can cause problems. Gel can reach the inside of the tooth through these gaps and increase sensitivity. So leaking fillings are repaired, temporarily or permanently, before whitening. Exposed root surfaces, worn tooth necks and cracks are also noted at the examination; if needed, these areas are covered with a protective barrier during treatment. This way the gel only touches natural enamel and treatment is more comfortable. For the general safety question, see our article is teeth whitening harmful.

Frequently asked questions

Can zirconia crowns be whitened?

No. The colour of zirconia and porcelain crowns does not change with whitening gel. Surface stains can be reduced with cleaning and polishing; for a lighter colour, the crown needs to be replaced.

When are fillings replaced after whitening?

There is usually a wait of about 2 weeks. During this time the colour stabilises and adhesive bonding strength returns to normal. The exact time is decided at the examination.

Will my composite fillings look darker after whitening?

They may. The natural teeth lighten while the filling stays the same colour. That is why fillings on the front teeth are often replaced to match the new shade after whitening.

Will my implant tooth whiten?

No. An implant crown is made of ceramic or zirconia and does not lighten with whitening. If you are thinking of whitening the neighbouring teeth, the crown's shade match should be planned in advance.

Does bonding change colour after whitening?

Bonding is also made of composite resin, so it does not lighten with whitening. Surface stains can be reduced by polishing; if a noticeable colour difference remains, the bonding can be redone to match the new shade.

Should I have whitening before getting veneers?

Yes, if you also want to lighten the teeth that will not have veneers. Whitening is done first, and once the colour has settled, the veneer shade is chosen to match the new shade.