Dental shade guide explained

What is a shade guide Dental?

Dental shade guide is a group of color simulated teeth that is used to select the proper shade for specific tooth for composite application or fabrication of a indirect restoration.

Guidelines for Proper tooth shade selection

1. Light location and it's source.
2. Surrounding environment.
3. Patient position
4. Distance from the patient
5. Condition of the tooth
6. Time of taking the shade
7. More than one person's opinion
8. Photographs

1- The light source

- Different sources of light have different effects on the color of an object which is the tooth and this is called metamerism.

Metamerism is a phenomenon occuring when two colors appear to match under one lighting condition, but not matching when the light source changes.

- The light source that is used for shade matching is the sunlight (6500 K), it is the traditional source of light that gives the exact shade of the tooth.

- Some opinions suggest that shade guide matching should be taken

during the noon time (middle portion of the day).

- The light of dental unit should resemble the daylight :

• should have around 5500 K of color temperature.
• Resembles the mid-day light
• Matches all the hues in the spectral curve.
• Color corrected source.

- The corrected light should have color rendering index (CRI) equal to or higher than 90.

- The doctor should not wear tinted eyewear or lenses during shade guide matching.

2- Surrounding environment

- The patient should remove the lipsticks, rouge and eyeglasses during shade guide matching, to avoid distraction and wrong shade selection.

- You should not place rubber dam during shade matching.

3- Position of the patient

- The patient should be in upright position during shade selection so that the dental professional should see the teeth under the same conditions of daily and social life.

4- Distance from the paitent

- Distance from which the shade is taken depends on size of the object being observed.

- To view color characteristics of a single tooth, It should be observed at a distance of 25 cm but during the shade matching (comparison between the tooth and shade guide) the distance should be 33 cm which is adequate to avoid any errors during the procedure.

5- Tooth condition

- You should clean the teeth and remove any calculus, plaque or stains which may hinder you from selecting the proper shade.

-During shade selection procedure, The tooth and the shade should be kept moist so as to resemble the oral environment.

6- Time of taking the shade

- The dental professional should do the shade matching procedure before treating the patient when his/her eyes are fresh not tired also the tooth will be moist not dehydrated during the treatment procedure.

- You should take about 5 seconds in shade matching process to prevent eye fatigue which may affect the shade selection.

- The shade guide tab should be on the same plane as the teeth and the same edge position as the teeth being viewed.

7- More than one person's opinion

- You should verify your color selection by asking a relative to the patient or dental assistant also the patient can share in that decision as this step compensates the visual color defects or eye fatigue of the dentist.

8- Photographs

- Photographs are not representing the true color of the teeth clinically but they can be sent to the dental lab technician to show him/her the extent of translucency and surface characteristics of each tooth.

Methods of shade selection

1- Traditional shade matching (Using Shade taps)

It is done by human eyes by matching range of colors from shade tap to the teeth adjacent or contralateral tooth being restored, then the shade selected is then transferred to the lab technician for fabrication of the restoration for better final outcome.

The main advantage of this technique is that it is less expensive and can be done anywhere but it depends mainly on perception of the naked eye of the operator which is unpredictable

a. older shade guides

Old shade guides are made of composite or acrylic teeth, they were used at the past but they are unreliable as they lose color faster.

b. VITAPAN classical shade system

They were the gold standard in shade selection until the appearance of VITAPAN 3D Master but it still the most commonly used method worldwide.

The patient is asked to smile and put the shade tap in front of patient's teeth from the darker shade to the whiter ones, then the most appropriate color is then picked and compared to the teeth.

c. VITAPAN 3D Master shade system

It is the first comprehensive shade guide tap that is presented in the dental field.

It is composed of 26 shade taps, they are arranged into 5 groups each group has equal value and each group has a range of hue and chroma.

1- The value group is chosen first for the tooth in question as it can be decided easily by the human eye.

2- Selection of the chroma is the second step.

3- The last thing to be chosen is hue.

d. VITA Linearguide 3D Master

It is the last shade guide produced by VITA, which also operates by the same principle of 3d master.

e. Custom made shade guides

They are made of composite blocks or fired porcelain blocks.

They can determine the accurate shade of final restoration as they are made from the same material.

2- Digital shade matching technologies principles

They are the most accurate and reliable than traditional shade tabs also Digital shade matching are more practical and easier to perform that old ones.

There are 2 main technologies

a. spectrophotometer

• Measures tooth color in references to known specific colors.
• Can be related to existing shade tabs.
• They are precise indicating graduations of value, chroma and hue.
• Examples of spectrophotometer VITA Easy shade, VITA Easy shade compact, MHT Spectroshade

b. colorometers

• Analyses the tooth color based on preloaded data that is related to a shade system.
• Determines the closest shade to the actual tooth color.
• Less accurate than spectrophotometer.
• Examples of colorometers Cynovad Shade scan, Shofu Shade eye NCC , Metalor Ikam shade analysis system.

Inspired by DR. Mohamed elhalawani.