How Cosmetic Dentists Colour Match Teeth

Almost any cosmetic dentist will tell you that matching the colour of a single front tooth is one of the hardest jobs in aesthetic dentistry. This guide explains why, and walks through the eight methods dentists and ceramists use to get the shade right.

A quick note: this is a technical look at shade matching. If anything here raises questions about your own treatment, call us at Marylebone Smile Clinic on 020 7126 8526.

Why colour matching a single front tooth is so difficult

A crown or veneer on one front tooth sits right next to natural teeth, so even a small difference in colour is obvious. The challenge is communicating every part of the colour of the reference tooth to the ceramist, while also allowing for the shade contribution of the underlying tooth (the abutment), the cement and the shape of the gums.

The demand for restorations that recreate the optical qualities of natural front teeth has driven research into all-ceramic systems and new shade matching techniques.

The 8 shade matching methods cosmetic dentists use

Many approaches have been developed to make shade analysis more predictable. The main ways of communicating and executing a shade are:

1. Written shade (Vita Classical, Vita-Master 3D, Vita Easyshade, Ivoclar Vivadent Chromascop)
2. Photographs of shade tabs or ceramic tabs (smartphone, compact, mirrorless, DSLR or medium format cameras)
3. Physical shade match with the technician
4. Custom shade match with the patient present in the laboratory
5. Custom shade tab made at the preparation stage
6. Multiple aesthetic trials
7. Multiple simultaneous fabrications
8. Calibrated digital photographs using L*a*b* values

In our experience, most of these methods share one weakness: the shade information has to be transferred from the communication medium into the ceramist’s understanding, and something can be lost along the way.

How each shade matching method compares

1. Written shade

A written shade refers to a shade tab, often made of acrylic resin that behaves quite differently from the feldspathic ceramic it is meant to represent. A written shade also cannot describe the variation at the biting edge or the gradual change in colour along the tooth. Automated digital shade-taking devices have anecdotally been reported to be of limited use, as they can be inaccurate and only give an average shade.

2. Photographs of shade tabs or ceramic tabs

Photographs can give better results, because they show the neighbouring teeth and how a reference point (the shade tab) relates to them. Ceramic shade tabs go a step further, as they are closer to the actual ceramic shade. The weak point is that the white balance of the clinician’s camera ideally needs to be synchronised with the technician’s reference monitor.

3. Physical shade match with the technician

Here the technician assesses the tooth in person under natural and artificial light. In practice this can be unreliable, as many technicians are more used to working from photographs, which are always available to refer back to. The exception is technicians who use physical shade taking as their main method.

4. Custom shade match with the patient in the laboratory

The technician sees the prepared tooth and the restoration in the mouth with the patient present. This can be hard to arrange, but it allows immediate shade corrections and re-checks. It is especially useful for dark underlying teeth and for thin, translucent restorations, where the colour of the cement matters more. The technician’s interpretation is still a factor.

5. Custom shade tab at preparation

The ceramist makes a custom shade tab at the diagnostic stage, which is then checked at later visits. It is a variation on using several trials to refine how well the shade blends in.

6. Multiple aesthetic trials

Several trial fittings allow small changes over a number of appointments. This takes time for the patient, dentist and technician, and is still subject to the issues described above.

7. Multiple simultaneous fabrications

This resource-heavy method aims to finish the case in a single trial. Several restorations are made at once, each subtly different in value (brightness), chroma (intensity), shape and effects, and the best match is chosen.

8. Calibrated digital photography with L*a*b* values

This emerging method takes the subjectivity out of shade taking. A white card is photographed through a cross-polarising filter next to the reference tooth and used to calibrate the receiving monitor. L*a*b* values (Hunter, 1948) express brightness (L) and colour (a, b) as numbers, so ceramic combinations can be tested against the values of the natural tooth. The technician can assess the proposed restoration digitally and adjust it. It takes the ceramist more time, but it is proven to be more reliable than the other methods.

Shade matching methods at a glance

Key takeaway: choose an experienced cosmetic dentist

Colour matching is not a simple task. When choosing a cosmetic dentist in London, look for a team with real experience in shade matching, like ours at Marylebone Smile Clinic. Before and after photos in a smile gallery are a good indication, as is a solid knowledge of colour and of ceramic and composite resin systems.

New to cosmetic treatment? Read what a cosmetic dentist does, or see our guide on how to choose your perfect veneer colour, or what cosmetic dentistry costs in the UK.