OPD II Color and Perception(Laboratory)

is a product of the interaction of three

elements such as light source, object and

observer

Color

is the ability of the

observer’s brain to interpret the received stimuli

from the light that reflects on an object.

Perception

are integral factors to achieve an excellent tooth restoration

Color and Perception

contribute to proper shade selection in order to attain excellent esthetic outcome for tooth colored

restorations

Shade matching tools and methods

Color is measuring using this system interms of hue, value, and chroma

Munsell color system

On a Munsell color system .They justify the ________,_______,and _____ on how a color would appear. It is important to mention also that a keen sense of vision together with ______ _______ are necessary to appreciate these color dimensions

wavelength, intensity and purity

proper lighting

– is a dimension that classifies color as

red, orange, yellow, green, blue, purple, etc.

hue

– is a dimension of color that

shows the saturation, intensity or strength of a

color.

Chroma

is a dimension which refers to the lightness or darkness of a color

Value

• In Operative Dentistry, being able to match the color of the teeth with the composite material is quite a challenge. Color matching tools and instruments such as _________ facilitates shade selection.

dental shade guides

• is a color matching tool used in
  Dentistry.

Shade Guide

Shade guide are made of what?

ceramic, resin or some other form of plastic or acrylic material.

Shade tabs are usually arranged according to

color dimension.

Each tab has a number and a letter: The letter (A, B, C, D) represents _____ while the number (1, 2, 3, 4) represent: the ______ and ______within each hue group.

Hue Groups

Chroma and value

LETTERS

A-

B-

C-

D-

LETTERS:

A = Reddish-brown

B = Reddish-yellow

C= Grey

D = Reddish-grey

Numbers

1=

4=

NUMBERS:

1 = Lowest chroma or lightest

4= Highest chroma or darkest

is a process which showcases factors that would

facilitate efficient shade selection. The following are matching steps that would serve as a guide to

competently perform tooth matching.

Visual shade matching method

Three Pre-Shade Matching Steps:

1. Check color vision

2. Use color corrected lighting

3. Control surround/viewing conditions

This is the process of checking the acuity of the sense of vision of the clinician or the dentist. It is important to identify if the clinician has any color deficiency

Check color vision

Check color vision- This test for color discrimination competency is performed by creating pairs of shade tabs from two identical shade guides such as

A1-D4

The best light source is that of the white light. There are several specifications to take note of for correct lighting for shade selection.

Use Color Corrected Lighting

Meaning of CCT and CRI

Correlated Color Temperature

Color Rendering Index

There are several specifications to

take note of for correct lighting for shade selection.

Correlated color temperature (CCT), color rendering index

(CRI) and intensity of the light source should be given consideration.

correlates the influence of temperature with the

spectral color.

CCT- Correlated Color Temperature

Recommended CCT for shade matching

should have a light source at

5500⁰K and 6500⁰K.

is an average performance rating score for a light source based on comparison to reference color. Light source with 90 or higher are recommended

CRI- Color Rendering Index

Intensity or illuminance is measured in lux (lx) and should be between

1000 and 2000 lx

External factors greatly affect color perception. This is performed by eliminating factors seen in the surrounding such as color of the walls (painting the walls neutral gray instead), distracting bold colors seen on the patient should also be eliminated such as sparkling jewelry, bright clothes, reflective eyeglasses and colored lipstick

Control Surround/ Viewing Conditons

Five Shade Matching Steps

1. Perform at the Beginning

2. Set Light and Observer

3. Use appropriate technique

4. Communicate

5. Verify

Visual shade matching

should be performed at the

Beginning of the appointment

This practice is recommended because tooth dehydration occurs over time during restorative field isolation thereby making the tooth to appear lighter, less chromatic and more opaque. This practice also assures that the clinician’s visual system is not yet fatigued nor strained

Perform at the beginning

This procedure identifies the correct viewing distance and position.

Set light and observer

correct viewing distance and angle of illumination

Distance – 25 to 35 cm (10-14 inches)

Angle of illumination / Optical geometry - 45/0 degrees

Use Appropriate Technique – These are methods applied during shade matching such as:

a. Selection of appropriate shade guide

b. Selection of appropriate shade guide positioning

c. Technique

d. duration

Selection of appropriate shade guide is dependent on the

preferred brand of shade guide

Selection of appropriate shade tab positioning – Never place the shade tab in

front or behind the natural teeth

when no adjacent tooth the ideal shade tab position is on the

same plane and the same vertical (cervical to incisal) orientation.

Adjacent teeth present - position the shade tab between the upper and lower teeth, vertically or horizontally to the ________ of the natural teeth.

Longitudinal Axis

Technique in five shade matching steps

Macro-Mini shade Matching Technique

3 phases of Macro-Mini shade matching technique

Macro Phase

Mini Phase

Micro Phase

This is looking at shade selection procedure in a bigger scale through a quick glance and choosing potential tabs. It is performed by positioning the entire shade guide close to the tooth whose color is being matched and moved laterally until a matching shade tab is identified.

Macrophase

– This is performed by clustering potential

shade tabs together. From these shade tabs, choose the one that best matches the natural tooth from the incisal, middle and cervical third.

Miniphase

This is looking at the picture in a more

detailed way after a best shade tab match have been

identified. This is performed by taking note details such as

differences in hue, value and chroma, local color

characteristics and appearance

Microphase

Using short glances is best in discerning the difference between two colors. This is performed by glancing at the target shade between?

5-7 Seconds

This is the next step in the shade matching process which is to capture, record , and communicate the selected tooth shades. This is made possible by documenting through the aid of digital photography and sketches

Communicate

Finals step in shade selection where color of restoration be direct or indirect is confirmed

Verify

on a direct composite verification is done by a?

Mockup restoration or simply applying and light curing a small increment

Verification is done by a mockup restoration or by simply applying and light curing a small increment of the selected composite material to the area of the tooth corresponding to the selected shade

Direct Composite