Principles of Esthetics

CONTENTS

• INTRODUCTION• NEED• DEFINITIONS• CLASSIFICATION• PRINCIPLES• COLOR• SMILE DESIGN ANALYSIS• STRUCTURAL ESTHETIC ELEMENTS• CONCLUSION• REFERENCES

Introduction

• Organised & systematic approach ….

• Final result..

• Smile, is a persons ability to express a range of emotions with the structure and movement of the teeth and lips can often determine how well a person can function in society

IT IS ESTIMATED THAT 50% OF PERSONS SEEKING DENTAL TREATMENT ARE ACTUALLY ESTHETIC IMPROVEMENT.

WANT BASED

NEED FOR ESTHETIC DENTISTRY

DEFINITIONS

Esthetic

Concerns with beauty or the appreciation of

beauty. (Oxford Dictionar

Dental Esthetics

The application of the principles of esthetics

to the natural or artificial teeth and restorations. (GPT

1999)

Esthetic reshaping

Modification of the surfaces of teeth to improve appearance

Esthetics (adj. 1798)

1. The branch of philosophy dealing with beauty.

In dentistry, the theory and philosophy that deal with beauty and beautiful, esp. with respect to the appearance of a dental restorations, as achieved through its form and or color. Those subjective and objective elements and principles underlying the beauty and attractiveness of an object, design or principle.

Esthetic Dentistry

can be defined as the art and science of dentistry

applied to create or enhance beauty of an individual

within functional and physiological limits.

Cosmetic dentistry

Is application of the principles of esthetics and

certain illusionary principles, performed to signify or

enhance beauty of an individual to suit the role he

has to play in his day-to-day life or otherwise.

COMPOSITION means the act of combining elements or parts to form a whole. There are various physical attributes of the elements of a composition that impart the esthetic value.

Contrast: It is that factor which makes the various elements of a composition visible. The eye can differentiate the parts of an object due to contrast of colors, lines, patterns, textures, etc.

The relationship between the different parts of the face (facial), the teeth and the gums (dental) made visible by contrast constitutes the dento-facial composition.

PRINCIPLES

Dental FACIAL

DENTAO FACIAL

UNITY : Prime requisite for a composition is unity that will give different part of the composition the effect of a whole.

STATIC

DYNAMIC

Unity between different parts of the face, and teeth is essential to give the effect of oneness or wholeness to the dento-facial composition

DOMINANCE:

It exists when a strong centralized structure is surrounded by well-demarcated, characterized structures. In a dento-facial composition it creates immaculate unity leading to a harmonious composition. The absence of dominance makes the composition weak. Color, shape and size are the factors which can control dominance.

COHESIVE AND SEGREGATE FORCES:

Any element which tends to unify a composition is a cohesive force. A border is a cohesive force, as well arrangements of elements in a definite form or according to a principle. e.g. two parallel objects or an encircling frame (l ips bordering the anterior teeth).

Segregative forces are those elements which break the monotony of the composition. Naturalness has combination of cohesive and segregative forces. A proper mix of segregative and cohesive forces adds variety to the composition making it more dynamic and interesting.

SEGREGATIVE FORCES ARE REPRESENTED BY ELEMENTS ARRANGED INAN INTERESTING MANNER ,REMINDER OF AN INTERESTING THING OR EVENTS, SUCH AS CLASS I ARRANGEMENT.

SEGREGATIVE FORCES ARE THE NECESSARY ELEMENTS THAT ENHANCE THEESTHETIC VALUE OF A COMPOSITION.

SYMMETRY : Symmetry refers to the regularity in the arrangement of forms or objects.

HORIZONTAL OR RUNNING SYMMETRYarrangement of forms either from left to right

RADIATING SYMMETRY

from a central point to either side like a mirror image

The horizontal symmetry looks repetitive and uninteresting while the radiating symmetry looks

dynamic and interesting.

In a dento-facial composition radiating symmetry of the teeth is more esthetically appealing and is

associated with youthfulness while horizontal symmetry is less appealing and is associated

with aging.

PROPORTIONTo be able to give a certain mathematical

representation of beauty for numerically expressing the relationship of the various units that combine to make a composition, the term proportion is used.

The relationship of the various units which are different from each other in a composition but are associated with each other through a certain repetitive mathematical factor is the repeated ratio.

The proportion between the various elements of a harmonious composition, in which the cohesive and segregative forces are equally balanced and which has its various units in an esthetically appealing respective proportion to each other is the golden proportion.

Key principle found in nature,art and architecture.basis of modern theory of dentofacial estheticsRelated to principles of cephalometrics and anthropometrics

GOLDEN PROPORTION RATIO : 1.618 : 1 : 0.618

• The dentofacial characteristics determined from the golden proportion include width of both centrals to height of centrals .

• 78% is ideal

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• If the ratio is applied to the smile made up of the central, lateral incisor and the mesial half of the canine, it shows that the central incisor is 62% wider than the lateral incisor which in turn is 62% wider than the visible portion of the canine which is the mesial half, when viewed from the front.

Application of sizing the central incisors from certain facial measurements is known as the 1 to 16 theory, whereby the height of an ideal maxillary central incisor from the incisal edge to the gingival crest is 1/16th of the distance from the inferior border of the chin to the inter papillary line.

The same tooth width can be measured from the mesial to distal contact areas and is 1/16th of the distance measured from either zygomatic prominence through an imaginary facial midline.

Once the size for the central incisor is determined it is essential to design its outline form. The facial harmony method can be applied to relate the tooth form to the facial form.

Various facial shapes are identified and descriptions such as

Ovoid, square, tapered and combinations of these are used . The same shape when inverted can be applied to the central incisor design. This shape acts as guideline for the outline forms of other maxillary teeth.

BALANCE: It is achieved when there is an exact equilibrium between the forces present on either side of the fulcrum in a composition. In dentistry this implies the balance of the elements in relation to the midline.

Visual tension is the tension brought about by the presence of certain elements that cause an imbalance in the given composition.

If the presence of these factors is closer to the fulcrum,

the effect of the tension into the fulcrum, the effective

tension induced is more magnified as against their

presence further from the fulcrum.

COLOR

Dimensions of color

Color cannot be perceived without light, which is a form of electoro-magnetic energy visible to the human eye. The visible spectrum of light lies in a narrow band of 380nm to 760nm. It has the ability to stimulate the cells in the retina which is interpreted by the brain, discerning the sense of color.

Clark stated that “Color, like form, has three dimensions”.

HUE : In Munsell’s words, “It is that quality by which we distinguish one color family from another”.

Generally there are six hue families. Violet, blue, green, yellow, orange and red. For example, in the Vita shade guide there are four hues A, B, C and denoting reddish brown, reddish yellow, grayish and reddish grey respectively.

CHROMA :

In Munsell’s words, “it is the quality

which we distinguish a strong color from a weak one

“Human teeth fall into the yellow to yellow red area of

the Munsell color order system. Pale colors have a

low chroma whereas intense colors have high chroma.

VALUE :

Value or brilliance is the relative blackness or

whiteness of color. On a scale of black to white, white

has “high value”, black has “Low value” and Midway

between black and white is the medium grey. Value is

the only dimension of color that can exist by itself.

Opacity and Translucency: As light strikes a surface,

it is either totally reflected, totally absorbed or a

combination of both. Opaque objects reflect all or most

of the light that is incident on them whereas transparent

objects transmit all of the light that is incident on them.

When part of the light incident on an object is

transmitted, while the rest is scattered, the property of the

object is known as translucency. It decreases with

increasing scattering within the materials.

Translucency, in effect, is the three dimensional spatial

relationship or representation of value.

Highly translucent teeth tend to be lower in value, since

they allow light to transmit through the teeth, while opaque teeth have higher value.

.

There might be inter tooth as well as intra tooth

differences in the translucency. Its extend can vary

according to the age of the patient due to the

degenerative and reparative changes in the enamel

and dentine.

To mimic natural teeth the effective use of restorative materials should largely depend upon this translucent effect.

METAMERISM

The change in color perception of two objects

under different light sources is called metamerism. For

example , a shade guide tooth matches the natural tooth

under incandescent light but not under fluorescent light.

This can be attributed to the difference in the radiant

energy of two different wavelengths of light.

The standardization of lighting condition during

shade matching diminishes the effect of metamerism.

FLUORESCENCE

The emission of light by an object at a different wavelength from that of the incident light is called fluorescence.

The emission stops immediately on removal of incident light. Teeth with flurosis stimulus in the range of 340nm to 410nm. This spectrum is in the blue range.

Thus, according to the principles of additive color, the emitted blue light acts with the yellowness of the tooth to produce a whiter tooth.

Fluorescing pigments incorporated in the

ceramic restorations by the ceramist and in the

composite restorations by the manufactures may

thus be advantageously used in altering the

perception of the final result.

The smile analysis/design process begins at the macro level, examining the patient’s face first, progressing to an evaluation of the individual teeth, and finally moving to material selection considerations.

SMILE DESIGNING

Is a process where by the complete oral

hard and soft tissues are studied and

evaluated and certain changes are brought

about which will have a positive influence on

the overall esthetics of the face.

“ A well designed smile is a product of consolidated

efforts accomplished by accurate diagnosis,

methodical treatment planning, use of advanced

materials and contemporary techniques rendered

by the skilled dentist”.

The esthetic orientation of the dental composition

with the entire facial composition can be achieved by

taking into consideration the references, smile elements,

proportions and symmetry.

These are the factors of esthetic compositions and they

help the dentist in determining tooth display, size,

arrangement and alignment during the diagnosis and

treatment phase.

The dento-facial frame constitutes the teeth and gingiva related to the lips and then to the entire face.

The oral frame is determined by the anatomy and mobility of the tissues when in function surrounding the teeth and gingiva .The exposed portion of the oral elements i.e. teeth and gums within the oral frame during a smile is called the smile window.

.

References can be classified as

Horizontal references,

Vertical references,

Saggital references and

Phonetic references.

STRUCTURAL ESTHETIC COMPONENTS

1.Facial components

2. Components of smile

3. Dental components

4. Gingival components

Facial features

Tooth visibility

Lip lineSmile lineUpper lip curvatureNegative spaceSmile symmetry

Dental midlineGolden ruleAxial alignmentDental morphologyContact points

Gingival morphology

Gingival contour

HORIZONTAL REFERENCES:

The horizontal perspective of the face is provided by the interpupillary line the commissural line.

VERTICAL REFERENCES:

The facial midline serves to evaluate the location and axis of the dental midline and the medio-lateral discrepancies in tooth position.

The inter-pupillary line and the facial midline emphasize the ‘T’ effect in a pleasing face. The dental midline, if perpendicular to the inter-pupillary line and coinciding with the bridge of the nose and the philtrum, produces an attractive orientation of the smile.

FACIAL ANALYSIS Frontal View

Facial analysis is checked at a conversational distance. The clinician uses a series of horizontal and vertical lines to determine the size and proportion of the face from chin to hairline and also the relationship of the patient’s face and dentition in space

John R Calamia, DCNA 2011

• A profile view allows clinicians to visualize an important imaginary line called the Rickett’s E-plane. A concave profile may call for a more prominent position of the maxillary anterior teeth with final restoration ofthe anterior teeth, whereas a more convex profile may require a more retruded positionof the final restorations.

• Other imaginary lines form the nasal/labial line angle. In men the nasal-labial angle is generally 90 to 95, whereas in women it is generally 100 to105.

• Incisal and Occlusal Analysis

John R Calamia, DCNA 2011

• Phonetic Analysis

• Dental Analysis

John R Calamia, DCNA 2011

SMILE ELEMENTS:

The extent of the smile is outlined by the curvature of the upper and lower lip and the position of the angle of the mouth, and it determines the degree of exposure, both in the anterior and posterior teeth, gingiva as well as the width of the buccal corridor

Smiles can be classified as passive, active (moderate) and laugh.

In a passive smile the lips are parted slightly away from the rest position expressing content, passion, desire, surprise, etc.

• In an active smile the lips move to a significant extent away from the rest position displaying more teeth and even gums, expressing joy, welcome, happiness, etc.

• Laugh is an instant fluctuation from an active smile position where the facial muscles instantly act leading to maximum exposure of the teeth and gums. Humorous and funny situations usually lead to such an expression.

SMILES?

S - size and golden proportion

M - midline and canting

I - axial inclination

L - Lip line vs incisal edge of teeth.

E - extra hard tissue guidelines, contact points, arch form.

S - soft tissue conditions, gingival symmetry

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TOOTH VISIBILITY:

It is more important for females than males as the average exposure of teeth is twice in females as that of males.

AGE

Feminine type of smile line

Masculine type of smile line

SMILE COMPONENTS LIP LINE DENTIST HAVE ARBITARILY CLASSIFIED THREE TYPES OF SMILES THAT,RELATING THE HEIGHT OF UPPER LIP RELATIVE TO THE MAXILLARY ANTERIOR CENTRAL INCISORS

High lip line Medium lip line

Low lip line Anterior low lip line

Lip and lip lines:

Length, curvature , shape of the lips significantly influence the amount of tooth exposure during rest and in function.

A prominent tooth display is associated with a youthful smile and most patients would like to seek the benefit of the same. Some researchers demonstrated that the average maxillary incisor display with the lips at rest is 1.91mm in men and 3.40 mm in Women .Patient’s with short upper lips and younger patients generally display more maxillary tooth structure which may be up to 3.65mm.

UPPER LIP LINE

Helps to evaluate the length of the maxillary incisor exposed at rest and during smile and the vertical position of the gingival margins during smile.

The upper lip line can be classified as low, medium or high depending upon the amount of tooth or gingival display that is available at rest of during a moderate smile. The gingival margins may be displayed in high lip line cases.

The most apical position of the gingiva over the facial aspect of the maxillary central incisor and canine is slightly distal to the long axis of the tooth while in the maxillary lateral incisor it is at the long axis of the tooth. This is called the gingival zenith.

Whenever a patient displays the gingival margins easily on smiling or speaking, a definite pattern of the gingival display can be recorded. This pattern can be either esthetic or unesthetic .

A smile can be termed “toothy” if more than 6mm of incisal display is seen at rest position or “gummy” if more than 3mm of gingival tissues are displayed in moderate smile.

LOWER LIP LINE

Helps to evaluate the buccolingual position of the incisal edge of the maxillary incisors and the curvature of the incisal plane

SMILE LINE: It is an imaginary line passing through the incisal edges of the upper anterior teeth. The smile line usually coincides or runs parallel to the inner vermilion border of the lower lip.

In a youthful smile the incisal edges of the central incisors and canines are aligned on a convexity and are longer than the lateral incisors, incisal embrasures gradually deepen from central incisor to the canine, giving the appearance of the wings of a gull.

C) UPPER LIP CURVATURE

Directed upwards Straight

Slightly downwards Pronounced downwards

D) NEGATIVE SPACE (buccal corridors) : DARK SPACE APPEARS BETWEEN THE JAWS DURING LAUGHTER AND MOUTH OPENING

The lateral negative space exists between the labial surface of maxillary teeth and the corner of the mouth while the buccal negative spaces appear in the buccal vestibule on either side of the buccal aspect of posterior teeth.

Obliteration of these essential spaces by dental elements like

bulky canines,

wide arches or

over-contoured restorations can lead to an unattractive smile.

Excessive negative space seen in cases of

missing premolars or

palatally placed posteriors and a constricted arch also appear unesthetic.

GRADATION : WHEN THE TWO SIMILAR OBJECTS ARE PLACED AT DIFF.DISTANCE CLOSER WILL APPER LARGEST.

THIS FRONT-BACK PROGRESSION IS DETERIMED BY ARCH FORM AND KEY TOOTH THAT ASSESSES THIS NATURAL TRANSITION.

Progressive abating in a dental composition:

When similar structures are aligned in an arch form one after the other, they appear to progressively abate in size from the nearest to the farthest. This gives an illusion of depth.

The essential requirement of the front to back progression in dental composition is the alignment of the contour of the labial surface at the incisal third, middle third and the gingival third of successive teeth in the arch.

The incisal mesio-buccal inclines should be well aligned to give a smooth progression from tooth to tooth. The buccal and lateral negative space progressively reduces the illumination on teeth to enhance the front to back abating effect.

The presence of poorly shaped teeth, differences in axial inclinations, tooth length discrepancies, discolorations, gingival disharmonies etc. can lead to a visual tension resulting in a disruption of the front to back progression.

E) SMILE SYMMETRYRADIATING SYMMETRY

HORIZONTAL SYMMETRY

DENTAL COMPONENTSA) DENTAL MIDLINE

It is an imaginary vertical line that separates the two central incisors.

Recommended protocola) Placing this midline precisely in accordance with facial midline

or in the middle of the mouth using the incisive papilla or labial frenum as landmarks.

b) Never establish it in a precise midline because it may contribute to an artificial appearance.

Mesiodistal width and inciso gingival height

Some osseous and dental landmarks

1.Bizygomatic width and maxillary central incisor width (1/16th)

2.Bizygomatic width and maxillary anterior teeth width (1/3rd)

3.Skull length and maxillary incisor length (1/20th)4.Skull circumference and width of the maxillary

incisors5.Nasal width and maxillary incisor width6.Angle of the mouth and maxillary anterior teeth

AXIAL INCLINATION

Is the direction of the anterior teeth in relation to the central midline and becomes progressively more pronounced from the central incisor to the canine.

There is a definite mesial inclination to all the anterior teeth related to the midline. The axes of the premolars and the first molar on either side also show mesial inclination in relation to the midline.

The perception of tooth inclination can be viewed

from the frontal aspect around the central vertical

midline, which acts like a fulcrum around which axial

inclination of teeth on either side exhibit a phenomenon

of balance of lines.

Natural smiles show a deviation from these standard

axial inclination. Deviations in axial inclination cause a

visual tension when beyond the point of equilibrium .

E-line or esthetic line is an imaginary line connecting the tip of the nose to the most prominent portion of the chin on the profile, ideally the upper lip is 1-2 mm behind and the lower lip 2-3mm behind the E-line. Any change in the position of the E-line indicates the abnormality in the upper or lower lip position.

The relationship of the maxillary incisal edges to the lower lip is a guide for the placement of the incisal edge position and length.

The pronunciation of the ‘F’ and ‘V’ consonants helps determine the position of the incisal edges.

On pronouncing ‘F’ and ‘V’ the incisal edges should make a definite contact at the inner vermilion border of the lower lip. Thus the position of the incisal third of the maxillary central incisor can be determind.

PHONETIC REFERENCES:

Phonetics play a part in determining maxillary central incisor design and position.

‘F’ and ‘V’ sounds : Tilt of the incisal third of the maxillary central incisors and their length.

‘M’ sound: To achieve relaxed rest position and repeated at slow intervals can help evaluate the incisal display at rest position .

‘S’ or ‘Z’ sounds determine the vertical dimension of speech.

PLEASING SMILE

A naturally attractive smile that evokes a feeling of beauty or harmony and complements the personality of the bearer is termed as a pleasing smile.

The natural pleasing smile may not necessarily

comply with all rules of symmetry or golden

proportion or may not exhibit perfect balance without irregularity of shape. However, the composition is esthetically appealing with unity within its various elements.

SMILE DOMINANCE :

Different facial features stand out differently in

the eyes of every beholder. In certain cases, the most

predominantly striking features of a face is the smile;

these are the “Dominant Smiles”.

The distinguishing characteristics observed in

people with pleasant smile dominance that can be

used as a guideline for creating the same are :

• The maxillary central incisors exhibit a strong presence by their size and form reflecting the personality of the individual.

The maxillary lateral incisors and the canines complement the central incisor in terms of proper shape and form.

Although numerically all proportions of the anterior teeth do not follow the rule of golden proportion, the teeth are so placed that they appear in suitable proportions with each other.

Well co-ordinated movements of the lips with

the other peri-oral musculature and corresponding

harmonious facial expressions, contribute to the pleasant

face during smile.

The complexion and texture on the face contrast with

the lip color, gingival and the teeth leading to a distinct

demarcation between the oral and the facial frame.

PERCEPTUAL ASPECTS – THE ART OF ILLUSION

Illusion is a figment of imagination where a perception of an object is created.

Fundamental and Principles

The art of creating illusions consists of changing perception, to cause an object to appear different from what it actually is. Teeth can be made to appear smaller, larger, wider, narrower, shorter, longer, younger, older, masculine or feminine.

One being subjected to light the most fundamental objects exhibits two dimensions, that is, length and width.

‘Principle of Illumination”.

The second artistic predilection of great importance in dentistry is the use of horizontal and vertical lines .

“Principle of Line”.

The artistic predilection exhibited in the principle of illumination can be maintained to change the size, shape and the overall form of the tooth through illusions.

Law of the face.

The face of a tooth is that area on the facial surface on both anterior and posterior teeth, that is bound by the transitional line angles as viewed from the facial i.e. labial or buccal aspect.

These transitional line angles mark the transition from the facial surface to the mesial, distal, cervical and incisal surfaces.

Shadows created as light strikes the facial surface of the tooth begin at the transitional line angles, these shadows delineate the boundaries of the facial form.

Thus the apparent face is that portion of the face that is visible to the observer from any single view. When maxillary anterior teeth are viewed from the front only the mesial half of the canine is visible however the entire incisor face is visible.

THE LAW OF THE FACE

Implies making dissimilar teeth appear similar by making the apparent faces equal.

The apparent face should be manipulated, not the actual face. This is more important in the canines and the posteriors as the ‘apparent face’.

The transitional line angles are relocated so that the apparent faces look equal, however this results in dissimilar areas outside the transitional line angles.

Similar faces produced attract light and appear high lighted while the dissimilar areas that are in a shadow appear to recede.

When the transitional line angles cannot be repositioned on a restoration, then the portion of the tooth can be stained darker to create an illusion that the transition line angle has been moved.

DENTAL MORPHOLOGY :

TEXTURE : Characterization of tooth surface is a function of two types of convexities and concavities.

- Anatomic grooves,facets,and prominence that exist in various degree on any tooth surface.

- The perikymatae,stipping,and rippling that may affect the enamel surface.

SHAPE OF THE TEETH Bizyomatic width and maxillary incisor width Nasal width and maxillary incisors

COLOR AND FACE OF TOOTH CONTOUR.

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Shape or form

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CONTACT POINT The lip line,incisal line and contact

line represent an ideal in cohesive forces of dentofacial composition.

From frontal view contacts are situated in a position that seems to go from incisal to

cervical and from centrals to canines.

PHONETICS

M & E SOUND - FOR INCISAL TOOTH DISPLAY IN REST POSITION - LENGTHOF THE TEETH AND INCISAL LINE.

F & V SOUND BUCCOLINGUAL PLACEMENT OF UPPER MAXILLARY INCISORS.

S SOUND VERTICAL DIMENSION OF SPEECH IS DETERMINED

F & V SOUNDS M - SOUNDS S & Z - SOUNDS

EMBRASURES AND INTERDENTAL SPACES

Interdental gingiva follows the contour of bone

GINGIVAL COMPONENTS

GINGIVAL MORPHOLOGY

GINGIVAL TISSUE AND RACIAL FACTOR

ALVEOLAR MUCOSA

GINGIVAL CONTOUR

GLOSS

Gloss is an optical property associated with a

smooth surface that produces lustrous surface appearance

and thus reduces the effect of color differences.

Increase the brilliance (value of the final result.) In

dentistry, unlike spectral colors, the restorative materials

have pigment colors incorporated in them. Predictable

restorative color outcome can only be achieved by proper

understanding of primary, secondary and complementary

factors.

PRIMARY COLOR

Are those colors that cannot be formed by mixing of

multiple colors. They occur naturally by themselves. For

example, red, yellow, blue etc.

COMPLEMENTARY COLORS

According to the additive principle of colors,

complementary colors can be used to lower the value of

the restoration and not to complementary color may be

added to the respective hue to decrease the value.

PERCEPTION OF COLOR.

The perception of color involves many physiological , and physiological aspects

THE LIGHT SOURCE.

The light source has the color of the emitted light and is described in color temperature (Kelvin.). The lighting environment makes a significant differences in the perception of color. The teeth and the shade guide should be sufficiently illuminated. The light reflected from a glossy surface obscures the viewer’s perception of light. Shadows should be eliminated as they reduce the available light and hide details.

The dental operator may be illuminated by combination of natural sunlight and artificial light,

The artificial light may be incandescent (predominantly) blue. Also the ratio between the task light (which falls directly on the working area) and the ambient light (derived from the surroundings), known as the contrast ratio, should be higher than 3:1, but lower than 10:1.

This can be attained by regularly measuring the intensity of light, cleaning the diffusers and the light sources any by replacing them when their effective life is over.

THE OBSERVER

The stimulus of light travels through cornea, lens, aqueous and vitreous humors and reaches the cones and rods of the eye.

The cones function for day light vision and color perception whereas rods are sensitive to the quantity of light perceived. These stimuli are then sent to the brain, where they are computed and interpreted as color. This complexity of color is further modified by the embryonic development of the brain, aging process, aberrations of color vision like color blindness, dichromatism, mental fatigue and drug intake.

THE OBJECT

The quality of the color of an object (the tooth) depends on its ability to absorb, reflect, transmit or refract the light energy falling on it. The surrounding environment greatly influences the color. The ceiling and the walls reflect light and should not be painted in bright colors. Neutral colors like grey or white should be selected.

CONTRAST EFFECTS

The background considerably affects the perception of color. Different contrasts effects that alter the color vision, should be understood.

SIMULTANEOUS CONTRAST

Is visualized when two objects are viewed at the same time. The light or dark contrast can be correlated to the surrounding environment like skin tone, hair color and brightness of adjacent soft tissues and teeth. Hence, brighter shades should be chosen for light toned patients and darker shades for pigment toned patients.

ACTUAL CONTRAST

Is influenced by the size and the chroma of the tooth. A brighter tooth looks larger while a darker tooth of the same dimension look smaller.

SHADE SELECTION

Shade selection is a complex procedure due to the variations and differences in the optical properties of the new generation of cosmetic restoration materials. It can be well accomplished by understanding the fundamentals of color and adopting a proper methodology of matching shades. The effective communication with the laboratory and precise fabrication and meticulous finishing of the restoration will affect the color of the final restoration.

SHADE SELECTION SEQUENCE

Any color modification procedures like bleaching or microabrasion should precede color selection after ensuring color stabilization.

Make the shade selection at the beginning of the procedure as well as over different appointments (diagnosis, prophylaxis etc.)and cross check these observations.

View the patients at eye-level. The operator should stand between the light source and the patient.

In a contrasting environment, colors look more intense and brighter. Hence it is wise to ask the patient’s to remove artificial lip color.

Place the tabs as close as possible to the area that is being checked.

Moisten the tab and eliminate the worst match.

Evaluate the value (upper to lower). Value is the most important factor in shade matching. If the value blends, small variation in hue and chroma will not be noticeable. The value is to be matched with eyes half closed.

After value, mark the translucency

Match the chroma (more or less saturated) and finally, hue in that order.

To avoid hue sensitivity, rapid observation is made for 5 seconds (not more than 20 seconds). Look away, ideally stare at a blue surface, which will readapt the vision to the orange yellow portion of the spectrum.

Match prior to tooth preparation, since preparation dehydrates and changes color due to the debris of preparation.

Match the tab with the opposing tooth also.

Metamerism complicates color matching, as the tabs look different under different light sources. The best approach is to use three light sources; cool white fluorescent light, incandescent operatory lamp and day light if possible.

• When in doubt, always select higher value and lower chroma, since it is easy to lower value and increase chroma

Shade tabs of different batches don’t always match, hence it is wise to sent the actual selected shade tab to the technician.

Make a decision regarding relative translucency, area of hypo calcification, increase saturation, crack lines surface texture and other characterization. Make a drawing of the facial surface and record all patient information graphically.

It is to be noted that smile design should always be a multifactorial decision-making process that allows the clinician to treat patients with an individualised and interdisciplinary approach.

ESTHETIC DENTISTRY IS ART OF DENTISTRY IN ITS PUREST FORM.

GOAL IS NOT TO SACRIFICE FUNCTION,

BUT TO USE IT AS FOUNDATION FOR TREATMENT.

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fundamentals of esthetics; Claude R. Refenacth.