shade registration- principles, systems and clinical

D-r Rangel Todorov

SHADE REGISTRATION- PRINCIPLES, SYSTEMS AND CLINICAL

PROTOCOL. TRANSLUCENCY

In our daily practice there are two ways to determine the color of teeth :

- Visually, manually;

- With special devices;

In visual color determination, the dental practitioner looks for a match between the available dental tissues and the set of color standarts, arranged in a shadeguide, used by the dentist.

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Shadeguides based on ceramic materials

• Vita Classical; Vita Lumin

• Vita 3D Master

• Vita Linearguide

• Vita Bleachguide 3D Master

• Chromascop (Ivoclar Vivadent)

• Vintage Halo Shade Guide (Shofu Dental)

• Bioform

Shadeguides based on composite materials

• Venus (Heraes Kulzer)

• Esthet-X (Dentsply)

• Filtek supreme (3M)

Shadeguides for soft tissues

• Ivocap Plus Gingiva Indicator (Ivoclar Vivadent)

• 4 Gummy gingiva- Indicator Set ( Shofu Dental)

Clinically made individualized shade guides

The Definitions of the Three Characteristics of Every Color are:

• HUE: This distinguishes one color family from another. It can also be called the parent or source color, and is interchangeably used with the word ‘color.’

• VALUE: The lightness or darkness of a color. All colors can be described as being light, medium or dark in tone, such as a pale blue sky or a dark blue sea.

• CHROMA: Refers to a color’s purity or its brightness or dullness of a color. For example, the stronger or brighter a color is, the higher its chroma. Every color can be identified by how bright/intense/saturated it is or how dull/de-saturated/less intense it is. You can alter the chroma of a color by adding white, grey, another color, its color complement or black. Chroma is also called saturation and intensity.

Vita ClassicalIn 1938 the company VITA Zahnfabrik was the first

one to present a shade guide, which is a result of epidemiological study of the distribution of dental shades.

In 1956, the VITA Lumin Vacuum Shade Guide was introduced, making the first attempt to create universal standard for color determination of teeth.

Vita Classical• Main principle of construction of the shade guide is

the hue;

• The color space is divided in 4 groups- A, B, C and D;

• In group A the dominating colors are red and brown;

• In group B- red and yellow;

• In group C- grey;

• In group D- red and yellow;

• Each of the main groups has sub groups which are marked with numbers- 1, 2, 3 and 4;

Vita Classical• This means that the total number of available colors

in the shade guide is 16;

• Increasing number in sub-groups means increasing saturation of the dominant color;

Vita classical

• There is also an alternative way of ordering the tabs in the shadeguide- according to the value scale;

• There are no subgroups and the ordering of the tabs is as follows- B1, A1, B2, D2, A2, C1, C2, D3, A3, D4, B3, A3.5, B4, C3, A4, C4;

Vita 3D Master• 26 tabs divided into five groups

• Main principle for construction- according to value;

• Chroma is positioned vertically inside the subgroup

• Hue is positioned horizontally within the group;

Vita 3D Master• Each tab of the shade guide has three designations;

• First - a digit, from 1 to 5 indicates the number of the group and the value ( smaller number shows higher brightness);

• Second - a letter- M, R and Y. They are connected with hue characteristics of colorant represent a color tone, which is Reddish or Yellowish compared to the Medium ones.

Vita 3D Master

• Last digits on the tabs- 1, 1.5, 2, 2.5 and 3 denote the level of saturation - the larger the number is, the more color saturated the tab is;

Vita 3D Master enhancements to Vita Classic

• The degrees of value are more varied;

• The range of the color tone has increased with respect to the red spectrum;

• The color tabs are more evenly spaced in the color space;

• The group division is better;

Vita LinearguideIn 2006 as a natural development of the Vita 3D

Master shade guide, this new development of the VITA company appeared, proposed by Prof R. Paravina. The color scheme is based entirely on 3D Master, incorporating all of its 29 shade tabs and we may define it as a innovative way of distributing color standards.

Vita Linearguide• Color determination with the Vita Classical is a one-

step process, however it is difficult due to the simultaneous selection between all the shade tabs;

• Defining the color shades with the Vita 3D Master is a three- step process

Vita LinearguideWith the help of Vita Linearguide the process of color determination is:

• Color registration takes place in two stages;

• The choice of a tab is related to the selection between a smaller number of color standards;

• The order of the shade tabs is based on Value ( as 3D Master shade guide);

• There is one major highlight guide - Value Guide. We start color determination, first step, by using this ,,mini shadeguide,,.

Vita Linearguide• The remaining tabs are divided into five groups,

separated into ,,sub- shade guides”;

• The determination of the color tone(HUE) by subgroups is carried out in the first stage of color registration;

• Choosing a tab from the main ,,sub-shade guide,, directs us to the one of the secondary sub- shade guides, where appropriate Hue and Chroma are determined;

Vita Bleachguide 3D Master• This shade guide is used to determine tooth color in

bleached teeth and evaluate whitening of hard dental tissues;

• It has 15 tabs, that represent 29 shades approved by the American Dental Association;

• It helps with the color assessment and enables easier communication between the dentist and the patient;

Vita Bleachguide 3D Master• This shade guide follows a logic of arrangement

identical to the Vita 3D Master shade guide;

• Value is the defining indicator in structuring;

• Numbers from 0 to 5 on the tabs indicate the degree of Value;

• The indices M1 through M3 correspond to the color tone (Hue) of the relevant M group of the 3D Master Shade guide;

ChromascopThe color space in this shade guide is divided into five groups according to the dominant color;

• Group 100- the dominant color is white;

• Group 200- the dominant color is yellow;

• Group 300- the dominant color is light brown;

• Group 400- the dominant color is grey;

• Group 500- the dominant color is dark brown;

Chromascop

• Each group has four subgroups;

• The higher the number - the more Chroma and less Value in the tabs.

BioformThe total number of shade tabs in the shade guide is

24;

The color space is divided into four groups according to the dominant color:

• Red- brown;

• Yellow;

• Red- gray;

• Gray;

Shadeguides for soft tissues

In order to achieve optimal aesthetic results, color matching of hard dental tissues is not sufficient in some clinical cases.

An appropriate color combination of the reconstituted soft tissues with those present in the oral cavity or skin is also required.

Shadeguides for soft tissues• Gingival tissues have a wider color range compared

to the natural hard dental tissues;

• Value and Hue are broader and Chroma narrower than the corresponding characteristics of teeth;

• The base of the prosthetic structure - removable or fixed, can be made using standard or individually made shade guide for soft tissues;

• With these color standards one can emphasize the individual features of the soft tissues in the maxillofacial region;

Gummy gingivaIn this shade guide there are four gingival colors

available as numbers:

• 1- light pink;

• 2- medium pink;

• 3- medium dark pink;

• 4- dark pink;

• Gummy gingiva is made as an accessory to the shade guide for teeth, enabling the standard tabs to fit inside it, therefore ensuring optimal conditions for correct soft tissue shade determination.

Ivocap Plus Gingiva IndicatorThis shade guide has two parts which correspond to

two main materials used to restore soft tissues-acrylic and ceramic;

The part for soft tissues offers four tabs: P- pink, US-L-light pink with threads, US-P- pink with threads and PREF-preferred;

The shadeguide for ceramic masses has ten tabs:

-basic( standart)- G1, G2, G3, G4 and G5

-gingival modifiers- GM1, GM2, GM3 and GM5

-gingival opacifier- GO


It is not always easy to determine the color match between natural teeth and the set of tabs which are available in standart shadeguides.

Consideration should also be given to the material of the final restoration- composite or various types of ceramic materials.


These shade guides are made from the material as the final restoration.

As an advantage , besides the personal color nuance, the possibility to perform several variants can be indicated, depending on the thickness of the layer, the type of surface, the degree of glazing and the customization of some color features.

Magnifying glasses with incorporated light

It is a tendency to apply constant, unchanging and closest to natural light for shade matching.

The light source could be mounted on the ceiling or the wall, but hand held sources are also available.

These devices are a combination of magnifiers and light sources that emit light that is optimal for shade matching.

Practical advises in visual shade determination

Light source requirements:

• Color temperature 5500 Kelvins;

• CRI Index at least with value 90;

• Intensity of light in the dental office- 18-28 000 lux.;

• Light intensity in laboratory- 28 000 lux.;


The surrounding colors have their influence:

• Patient clothing;

• Clothing of support staff;

• The ceiling color must have a Value of 9 on Munsell scale;

• The color of walls and other surrounding surfaces in the dental office must have value 7 on Munsell Value scale;

• The color of the countertops must be 7 on Munsell Value scale and up to 6 on Munsell Chroma scale;


• Shade matching must be accomplished at the beginning of the patient visit;

• It is not necessary to determine the color in a single visit;

• It is possible to supplement the color information in a next visit;

• Teeth that are investigated for the purpose of shade determination must be clean without any trace of staining;


• It is preferable to use different light sources;

• Usually the patient is asked to stand by the window to use natural light. Prior to this, the color of teeth can also be determined in artificial light, fluorescent and incandescent;


• It is recommended to register color of teeth between 10 a.m. and 2 p.m.;

• The optimum distance for color registration is 25 cm.;

• Dental structures must be at the level of the eyes-this is how the most sensitive part of the retina is used;

• The time for the optimal color determination is about 15-20 seconds;


• If it takes a longer time to determine the color, it is recommended to shift the gaze to another surface (preferably in grey color);

• Eye rest is made by stopping the eye for at least 30 seconds. This results in balancing the color receptors in the retina so that the eye can again perceive the predominantly yellow shades of dental tissues;

• Squinting eyes also helps sometimes in proper shade determination;


• It is desirable to determine the color by dividing the tooth into three parts- incisal, middle and cervical/gingival;

• The tabs representing the shades must be placed under the lip and where possible in a place of a missing tooth;

• If the incisal edges of the tab from the shade guide and the tooth used for color determination are adhered to, the negative effect of binocular perception is avoided, and they are placed in one plane;


• The moistened surface of the tab used for color registering is as close as possible to the texture of the natural tooth structures ( dehydration in the enamel results a loss of transparency of 82%. The normal surface structure will be restored in at least 20-30 minutes);

• The position of the tooth in the arch also influences its color features;

• The lighter the tooth is the more vestibular its position appears in the oral cavity. It is suggested to choose the lighter between two shades for the upper jaw and the darker for the lower

Practical advises in visual shade determining

• However if we encounter difficulty in determining the color, we may choose a color standart that has lower Chroma and higher Value characteristics;

• The perception of color is the first impression that our patient has and can easily evaluate on his own. After this patients starts to assess the form, function and comfort of the restoration;

Shade matching devicesIn the last decades considerable advance in a

relatively new technologies is made and incorporated in the practice – machine assisted shade matching.

Shade registration devices

Devices and color registration system can be divided into:

• Colorimeters;

• Spectrophotometers;

• Digital devices and systems for digital imaging;

• Hybrid devices;

Colorimeters

Colorimeters are devices that, using their light sources, emit an instant beam of light that is reflected from the tooth's surface and subsequently captured by the apparatus, where it is processed and recoded in a meaningful format.

ColorimetersThese devices provide stable measurements on

transparent and translucent objects, but are uncertain when measuring complex and multilayered translucent structures.

Colorimeters consist of three main elements- a light source, detector and filters. These devices are less accurate than spectrophotometers because of the aging of the filters.

The measurement of the gingival, middle and incisal thirds creates an image of the entire tooth.

ShadeEye NCC It is one of the most old devices in the market

(1997). The unit was developed with the efforts of Minolta Corporation and the department for device researches of Shofu. The old name of the system is called ShadeEye EX. The modern version of the device has basic, body part and wireless, working part.

ShadeEye NCC Three to five measurements are made and the

results are averaged. The unit matches tooth coloragainst shade tabs of NCC, Vita Classical, Vita 3DMaster, Chromascop and Biodent shade guides.Through the infrared port, the processed colorinformation is transferred to computer. With aproprietary software, along with the digital picturesof the patient, all information is sent to to thelaboratory.

SpectrophotometerSpectrophotometers are deemed as the most

accurate, useful and applicable in the daily practice. They measure the amount of light energy that is reflected by an object in intervals of 1 to 2.5 mm across the entire visible spectrum.

These devices consist of a light source, a light scattering unit, an optical measuring system, a detector and a device for converting the light obtained into a signal that can be analyzed.

Spectrophotometers

Compared to the visual method, spectrophotometers offer a 33 % increase in accuracy and a color match in 93.3 % of cases.

The difference with colorimeters is that they analyze the scattering of the entire visible spectrum of 400-700 ηm, not the three major colors.

This quality of spectrophotometers makes them slower than the colorimeters.

Vita EasyShade CompactThe first generation of the device includes a main and a recording part. The main part has a light source and a small screen displaying the results of color determination.

Vita EasyShade Compact

The modern version of the Vita Easy Shade Compact has reduces dimensions compared to the first generation and the fiber optic cable has been removed ( the main and measuring parts are combined in one housing). It also has a specially developed software that facilitates the processing of color information.

Vita EasyShade CompactThis spectrophotometer is located on a base holder, in which the device is charged and the calibration plate is placed. Calibration of the device is required before each measurement of the color features of the dental tissues.


The fiber optic tip is about 5 mm. in diameter and contains 19 optical fibers, each 1mm In diameter. The device uses pseudo- circular geometry ( 0˚/ 0˚). The light source is a halogen stabilized incandescent lamp.


Various measurement modes are possible with Vita EasyShade Compact- single tooth, tooth area, mode-gingival, middle and incisal area, comparison mode and restoration color check.


This is one of the few devices that allows access to the distal teeth, the measurement itself is relatively comfortable for the patient.

The only drawback is it works only with the Vita’s shade guides and the small screen size of the device.

Spectro Shade MicroThe apparatus combines digital image acquisition with spectrophotometric analysis.

A combination of digital apparatus and LED spectrophotometer is used.

Spectro Shade MicroThis unit has a build in computer that has analytical software. The device consists of a halogen light source D65 ( 6500 K), which is directed to the tooth though fiber optic bundles and lenses to obtain uniform illumination of the field. The light emitted falls at an angle of 45 degrees and the angle of reflection is 0 degrees.

Spectro Shade Micro

Spectro Shade MicroThe camera has a built- in monitor that helps focus,

centre and visualize the image. Recording is fast, with only one tooth registered for color determination in each image.

Spectro Shade Micro

Spectro Shade MicroDue to the large volume of the working part, the device is not suitable for measuring distal teeth and often color registration is associated with patient discomfort. There are also difficulties with rotated and malpositioned teeth. It is not acceptable to include teeth, antagonists, lips and tongue in the image. The disadvantages are its high cost and image blurs, occurring despite optimal settings and operator experience.

Trios 3S Shape

TransparencyIn the field of optics, transparency (also called

pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light.

In dentistry there are three main terms associated with this phenomena – opacity, translucency and transparency.

Regarding their ability to pass light trough them, teeth are best characterized as translucent.

Translucency The term transillumination means – “Investigation of a tissue or an organ by passing a strong light through it”. The object of observation is located between the light source and the observer.

Translucency

The most frequent application of transillumination in dentistry is the visualization of proximal carious lesions. An advantage of the method is the registration of the caries where a x- ray examination would not provide the necessary information.

The most famous devices in this group are FOTI ( fiber- optic transillumination ) and DIFOTI ( digital fiber optic transillumination).

TranslucencyUsing the transillumination method, a novel

apparatus suitable for objectifying the location of the individual transparent area in frontal teeth was created.

Translucency

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shade registration- principles, systems and clinical

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