Dental Shade Guides are used to colour match dental patients requiring replacement prosthetic teeth. They are a set of artificial teeth made from either plastic or porcelain that represent the range of tooth shades available.
When considering a match for a prosthetic tooth, appearance is everything, and dental specialists consider hue, chroma, and value.
The hue refers to the colour itself, the chroma is the intensity or saturation of the colour, and the value is the brightness of the colour. All three of these components are considered vital for successful colour matching.
Most available guides focus on hue, though value is often believed to be most important for a good match. Optical brightness is the element the human eye is most sensitive to, due to the approximate 120 million rod cells we have in our eyes for detecting luminosity. Conversely, we only have 6 to 7 million cone cells, which are the other type of photoreceptor in the eye and the cells which determine colour.
This sensitivity to optical brightness is why a mismatch in value would be most noticeable to the patient and others if an appropriate match is not used.
Available Types of Commercial Shade Guides
There are several types of commercial shade guides available. The best known and most popular worldwide is the VITA Classic Shade Guide which groups 16 tabs of a similar hue into four collections (A: red-yellow, B: yellow, C: grey, D: red-yellow-grey), and then numerically orders the tabs within each group based on chroma.
For instance, a selected tab could be a B3. The Ivoclar Vivadent Chromascop Shade Guide is another hue-based shade guide, which has four chroma variations within five available hue groups.
The VITA 3D Master Guide is an updated shade guide by the same manufacturer of the Vita Classic which has ten additional shades, thus allowing more coverage of more clients. This guide is the only value-based guide available with the twenty-six tabs being divided into six value groups, before being further differentiated into three hue groups and the two or three chroma groups.
Principles of Shade Selection
If considering teeth whitening in Knutsford, a patient should look for a clinic that follows the universally understood and accepted principles of shade selection, which are also usually recommended by the shade guide manufacturers.
For instance, the guidelines for the Vita Classic state to match hue first based on which is closest to that of the client’s natural tooth colour, before then matching chroma.
A key point when matching is to avoid retinal fatigue or tired eyes, as this may hinder accuracy. It is often recommended that another shade guide ordered by value, or brightness is used – ensuring the comparison is made at arm’s length whilst squinting, to make absolutely sure of the selection.
Shade Selection Keys
There are several keys to remember when carrying out a shade selection for a patient’s prosthetic tooth. Firstly, ensure the matching is carried out in an environment optimally lit with natural daylight, as well as ambient light. This helps avoid the problem of metamerism when two shades appear to match well under certain lighting conditions but match poorly under alternative lighting.
Make sure the patient’s teeth are viewed at eye level, and that both the teeth and the shade guide are slightly wetted to avoid any surface textural irregularities.
It is important that neutral colours surround the teeth when matching, so patients should not wear lipstick or bright clothing – it can be helpful for the dentist to provide a grey patient bib.
How Dentists Use VITA Classic Model
When seeking a prosthetic tooth, it is most likely the dentist will use the Vita Classic Model to determine the best match.
When making the hue selection they will hold the shade guide against the patient’s tooth and try to eliminate any obvious mismatches in colour, before being left with one or two likely hue groups.
Once the hue group has been established, the dentist will then run the tabs of that hue along the tooth being matched to determine which of the group is the best chroma selection.
The value is determined last in this model – before the final selection is double checked via photograph. Often a value ordered tooth shade guide can be used as an extra check.
As a final visual revision, once they are down to only a few possible shade choices dentists will often take photographs with a digital camera and look at the images in grayscale. This can help to determine the closest match, particularly when considering brightness.
Some dentists may use digital shade analysers to assess a patient’s colour match. Spectrophotometers are considered the most accurate of these tools to use in dentistry, and the Easyshade Compact is the device manufactured by Vita.
Dental practices like Knutsford Dental Clinic offer a range of professional dental solutions including finding patients the perfect prosthetic teeth.
Established in July 2018, Superior Smiles is a new private dentist in Knutsford, Cheshire, with extensive experience we offer wide range of dental treatments for all ages.