Shade assessment and laboratory communication

Question 1

Important components of prescribing an aesthetic restoration

Answer 1

Shape
Colour
Surface texture
Translucency

Question 2

Communicating shape - diagnostic wax up

Answer 2

Shape and aesthetics
Tooth reduction
Occlusal contacts
OVD

Question 3

Communicating colour

Answer 3

Subjective shade assessment

Objective shade assesment

Question 4

Objective shade assessments

Answer 4

Colourimeter
-not that good
Image analysis
-helpful
-very expensive

Question 5

Subjective assessment

Answer 5

Shade taking
Colour perceived is determined by
-the illuminant
-the object
-the observer
Can be challenging

Question 6

Complications

Answer 6

Lighting conditions
Distracting strong colours
Colour variation within individual tooth
-white bands
-white framing
Translucency variation
-blue translucency
Surface reflection
-similar reflections
Individual colour perception

Question 7

Lighting conditions

Answer 7

Switch off operating light

Get pt to turn to window

Question 8

Distracting colours

Answer 8

Eyes fatigue quickly after 30s so need to be quick

Look at blue in between

Question 9

Describing colour

Answer 9

Munsell system

• hue (type of colour?)
• chroma (intensity of light/ saturation)
• value (increasing value as colour is added with white, decreases as black added)

Question 10

CIE colour space

Answer 10

Give dimension to colour
Plot hue, chroma and value
CIE Lab*

Question 11

Classic shade guide

Answer 11

Vita 
A-D differences in hue
Numbers differences in value
Shades do not cover entire colour space
Not evenly distributed

Question 12

3D shade guide

Answer 12

Equal distribution
Logical construction
Across - decrase in value
Down - increase in chroma
Hue shift between 3
-Rs are more red and Ls are more lellow

Question 13

Communicating surface texture

Answer 13

Photo
Study cast
-grind zone
-distal and mesial line angle
-central lobe
-depression

Question 14

Shade taking tips

Answer 14

Hydrated teeth
Swich off operating light
Multiple light source - daylight corrected 
Multiple opinions
Work quickly

Question 15

Laboratory communication

Answer 15

Planning - wax up? occlusion?
Patient communication
Pre-op impression
Working impression
Opposing impression
Inter occlusal record
Lab card
Shade: shape, translucency, surface texture

Question 16

3M2

Answer 16

A3

Question 17

Communicating shape

Answer 17

Sometimes simple - use adjacent teeth
Sometimes tricky, use:
-study cast
-photo
-diagnostic wax-up