PRINCIPLES IN AESTHETIC DENTISTRY

Dr. Maria Susan Benzy

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CONTENTS

• Introduction• History• Aesthetics• Basic Elements

- COLOR: Hue, Chroma and Value Shade selection Understanding and communicating Color

- LIGHT & SHADOW- SHAPE AND FORM- ILLUSION

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CONTENTS

• Smile Design• Facial Composition• Tooth composition

- Dental midline - Incisal lengths - Tooth dimensions - Zenith points - Axial inclinations - Interdental contact area (ICA) and point (ICP)

- Incisal embrasure - Sex, personality and age

- Symmetry and balance3

CONTENTS

• Soft tissue components - Gingival health

- Gingival levels and harmony - Interdental embrasure - Smile line

• Conclusion • References

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INTRODUCTION

Thy teeth are as a flock of sheep which go up from the washing, whereof every one beareth twins, and there is not one barren among them.-Songs of Solomon 4:2

( 9th century BC)

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HISTORY

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History contd..

Pierrie Fauchard (1678-1761)

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AESTHETIC

... you may look at a bed or any other object from straight in front or slantwise or at any angle. Is there then any difference in the bed itself, or does it merely look different? It only looks different. Well, that is the point. Does painting aim at reproducing any actual object as it is, or the appearance of it as it looks? In other words, is it a representation of the truth or of a semblance? Of a semblance [i.e. of the sensed object world]. The art of representation, then, is a long way from reality; and apparently the reason why there is nothing it cannot reproduce is that it grasps only a small part of any object, and that only an image.

(Republic, Book X, 598)

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AESTHETIC

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"Is the art and science of dentistry applied to create or enhance the beauty of an individual within functional and physiological limits.” Where as…………

Cosmetic dentistry is the application of the principles of esthetics and certain illusionary principles , performed to signify or enhance beauty of an individual within functional and physiological limits .

BASIC ELEMENTS

• COLOR• LIGHT & SHADOW• SHAPE AND FORM• ILLUSION

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COLOR

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COLOR

COLOR

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COLOR

Factors affecting color appearance of an object:1. Light source2. Observer3. Object

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COLOR

1. Light source– The most common light sources in dental offices

are incandescent and fluorescent, neither of which are pure white light.

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COLOR• Ordinary incandescent light bulb emits relatively

higher concentrations of yellow light waves

• Fluorescent light give off relatively high concentrations of blue waves.

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COLOR• Artists have traditionally chosen studios illuminated

by northern daylight, which can be close to full spectrum white light and often is used as the "normal" standard for judging light from other sources

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COLOR

HUECHROMA

VALUE

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HUEROY G BIV

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Color (HUE) RELATIONSHIP

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Color (HUE) RELATIONSHIP

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Color (HUE) RELATIONSHIP

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CHROMA

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VALUE

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SHADE SELECTION

1. Shade comparisons should be made at the beginning of a patient's visit.

2. The teeth to be matched should be clean. If necessary, stains should be removed by prophylaxis.

3. Brightly colored clothing should be draped and lipstick removed.

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SHADE SELECTION

4. Shade comparison should be made under different lighting conditions. The patient should be viewed at eye level so that the most color-sensitive part of the retina will be used.

5. Normally the patient is taken to a window, and the color is confirmed in natural daylight after initial selection under incandescent and fluorescent lighting.

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SHADE SELECTION

6. Shade comparisons should be made quickly, with the color samples placed under the lip directly next to the tooth being matched. This will ensure that the background of the tooth and the shade sample are the same, which is essential for accurate matching.

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SHADE SELECTION

7. The dentist should be aware of eye fatigue, particularly if very bright fiber optic illumination has been used. The eyes should be rested by focusing on a gray-blue surface immediately before a comparison, because this balances all the color sensors of the retina and re-sensitizes the eye to the yellow color of the tooth.

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UNDERSTANDING & COMMUNICATING COLOR

• Modified shade guides

• Custom shade guides

• Color sketches

• Photographs for communication

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UNDERSTANDING & COMMUNICATING COLOR

1. Determine the value level (squint)

2. Determine the chroma.

3. Determine the correct hue.

4. Analyze any difference that may remain between the tooth and the tab, and move in the appropriate direction to determine if a more exact match exists.

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LIGHT & SHADOW

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Fluorescence

It is the absorption of light by a material and thespontaneous emission of light in a longer wavelength.

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Opalescence:

Opalescence can be described as a phenomenon where a material appears to be one color when you observe light reflected from it and looks another color when you see light transmitted through it.

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Translucency:

This is another dimension beyond hue, chroma, and value that is significant when mimicking nature.

Translucency can be defined as the gradient between transparent and opaque.

Generally, increasing the translucency of a crown lowers its value.

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SHAPE AND FORM

Knowledge of the anatomy

Feminine smile- Rounded and open incisal and facial embrasures- Softened facial line angle

Masculine smile- Incisal embrasure more close and prominent

Resemblances to the contralateral tooth- Developmental grooves, prominence and other characteristic

forms

Surface texture- Stippling, concavity, convexity

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ILLUSION

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ILLUSION

The basic optical principles applied in dentistry include the following:

• Vertical lines accentuate length• Horizontal lines accentuate width• Contrast heightens visibility• Light reflection increases visibility• Light deflection decreases visibility• Shadows create depth• Light creates prominence

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ILLUSION

Prominent areas of contour are highlighted with direct illumination

Areas of depression are shadowed.

Size of tooth can be altered

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ILLUSION

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ILLUSION

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ILLUSION

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…when planning treatment for esthetics cases, smile design cannot be isolated from a comprehensive approach to patient care… Peter Dawson

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A smile design should include the evaluation and analysis of

- Facial composition

- Dental composition

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Facial composition

Two facial features play a major role :• The interpupillary line • Lips

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Facial composition

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Facial compositionThe horizontal and vertical dimensions for an ideal face:

Horizontal:

• The width of the face should be the width of five "eyes".

• The distance between the eyebrow and chin should be equal to the width of the face

Vertical:

• The facial height is divided into three equal parts from the fore head to the eyebrow line, from the eyebrow line to the base of the nose and from the base of the nose to the base of the chin.

• The lower part of the face from the base of the nose to the chin is divided into two parts, the upper lip forms one-third of it and the lower lip and the chin two-thirds of it

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Facial composition

Basic shape of the face when viewed from the frontal aspect:

SquareTaperingSquare taperingOvoid

The lateral profile :

StraightConvexConcave

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DENTAL COMPOSITION

Tooth components 

a) Dental midline 

b) Incisal lengths 

c) Tooth dimensions 

d) Zenith points 

e) Axial inclinations 

f) Interdental contact area (ICA) and point (ICP) 

g) Incisal embrasure 

h) Sex, personality and age 

i) Symmetry and balance

Soft tissue components 

a) Gingival health 

b) Gingival levels and harmony 

c) Interdental embrasure 

d) Smile line

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DENTAL MIDLINE

The vertical contact interface between two maxillary centrals

It should be perpendicular to the incisal plane and parallel to the midline of the face. Esthetically acceptable

Maximum allowed discrepancy = 2 mm and > 2mm discrepancy

(the dental midline is perpendicular to the interpupillary line.)

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DENTAL MIDLINE

The philtrum of the lipThe center of the philtrum is the center of the cupids bow

and it should match the papilla between the centrals.If these two structures match and the midline is incorrect,

then the problem is usually incisal inclination. If the papilla and philturm do not match, then the problem

is a true midline deviation.

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Midline should be

• Parallel to the long axis of the face: the line angle that forms the contact between the centrals should be parallel to the long axis of the face;

• Perpendicular to the incisal plane: the line angle that forms the contact between the centrals should be perpendicular to the incisal plane and

• Over the papilla: the midline should drop straight down from the papilla.

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Incisal lengths (incisal edge positions)

It serves as a reference point to decide the proper tooth proportion and gingival levels

Parameters used to help establish:• degree of tooth display• Phonetics• patient input

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Incisal lengths (incisal edge positions)

Phonetics• M sound: After pronunciation, the lips return to their normal

rest position, allowing evaluation of the amount of the tooth display in rest position

• E sound: The maxillary incisal edge position should be positioned halfway between the upper and lower lip during the "E" sound.

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Incisal lengths (incisal edge positions)

Phonetics• F and V sounds: Produced by the interaction of the maxillary

incisal edge with the inner edge of the lower lips' vermilion border. Thus, fricative sounds help to determine the labiolingual position and length of the maxillary teeth.

• S sound: During pronunciation, the mandibular central incisors are positioned 1 mm behind and 1 mm below the maxillary incisal edge.

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Tooth dimensions

The width to length ratio of the centrals = approx. 4:5 (0.8-1.0) or

Width should be75-80% of their lengthGuidelines for establishing correct proportions

• Golden proportion (Lombardi),• Recurring esthetic dental proportions (Ward),• M proportions (Methot) and• Chu's esthetic gauges.

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Tooth dimensions

• Golden proportion (Lombardi): The width of each anterior tooth is 60% of the width of the adjacent tooth (mathematical ratio being 1.6:1:0.6)

• Recurring esthetic dental proportion (Ward): The successive width proportion should remain constant as we move posteriorly form midline.

• M proportions (Methot): compares the tooth width with the facial width using a software.

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Tooth dimensions

• Chu's esthetic gauges: A series of gauges are available to make intraoral analysis easier. The gauges allow for

– fast, simple analysis and diagnosis of tooth width problems, tooth length problems and gingival length discrepancies;

– color coding predefines desired tooth proportions, quicker and easier to read than any other instrument;

– used as a reference guide between clinician and lab technician, hence reduces the incidences of miscommunications errors.

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• Maxillary central incisor: Approx. length of the central = 10-11 mm and the width ( 75-

80%)

• Maxillary lateral incisor: They provide individuality, are never symmetrical and

influence gender characterization.

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• Maxillary canine:

Support the frontal muscles - the size and characteristic of the buccal corridor is determined by the size, shape and position of the canine and

Canine depicts the personality characterization (masculine: vigorous and aggressive; feminine: delicate and soft).

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Central incisor is wider than the lateral by 2-3 mm and canine by 1-1.5 mm;

Canine is wider than the lateral by 1-1.5 mm and

Canine and central are longer than lateral by 1-1.5 mm.

Maxillary bicuspids: they play a very important role for arch design. They should fill the buccal corridor.

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Buccal corridorDark space (negative space) visible during smile formation

between the corners of the mouth and the buccal surfaces of the maxillary teeth.

Its appearance is influenced by • width of the smile and maxillary arch,• tone of the facial muscles,• positioning of the labial surface of the upper premolars,• prominence of the canines• any discrepancy between the value of the premolars and the

six anterior teeth.

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Zenith points

Establishing proper location of zenith points is a critical in alteration of mesiodistal dimensions of tooth

• Closure of diastema

• To provide the illusion of bodily movement and reduce exaggerated triangular form and

• Correction of tooth angulations.

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Tooth inclinations

The guide for labiolingual inclination is as follows:• Maxillary central incisor - positioned vertically or slightly

labial• Maxillary lateral incisor - cervical is tucked in, incisal edge

inclined slightly labially• Maxillary canine - cervical area positioned labially, cusp

tip lingually angulated

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Interdental contact area and point

Interproximal contact area (ICA):

• It is defined as the broad zone in which two adjacent teeth touch.

• It follows the 50:40:30 rule in reference to the maxillary central incisor

• The increasing ICA helps to create the illusion of longer teeth by wider and also extend apically to eliminate black triangles.

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Interdental contact area and point

Interproximal contact point (ICP):

• It is the most incisal aspect of the ICA.

• As a general rule, the ICP moves apically, the further posterior one moves from the midline

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Incisal embrasures• Should display a natural, progressive increase in size or depth

from the central to the canine. Failure :- teeth appear too uniform - make the contact areas too long and impart to the dentition a

box like appearance.

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Sex, age and personality Age - maxillary central incisor

Youthful teeth: unworn incisal edge, defined incisal embrasure, low chroma and high value

Aged teeth: shorter; so less smile display, minimal incisal embrasure, high chroma and low value

Sex - maxillary incisors

Female form: round smooth, soft delicate Male form: cuboidal , hard vigorous

Personality - maxillary canine

Aggressive, hostile angry: pointed long "fangy" cusp form Passive, soft: blunt, rounded, short cusp form

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Soft tissue

Gingival healthHealthy gingiva is usually• pale pink in color, stippled, firm and it should exhibit a matte

surface;• located facially - 3 mm above the alveolar crestal bone• located interdentally - 5 mm above the intercrestal bone

papilla should be pointed and should fill the gingival embrasure right up to the contact area.

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Interdental embrasure (cervical embrasure)

• If the most apical point of the restoration is 5 mm or less from the crest of the bone, then black triangles can be avoided

• Encourage the formation of a healthy, pointed papilla instead of the blunted tissue form

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Smile line

• An imaginary line along the incisal edges of the maxillary anterior teeth which should mimic the curvature of the superior border of the lower lip while smiling

• The centrals should appear slightly longer or, at least, not any shorter than the canines along the incisal plane.

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• Lip line refers to the position of the inferior border of the upper lip during smile formation and thereby determines the display of tooth or gingiva.

• The gingival margin and the lip line should be congruent or there can be a 1-2 mm display of the gingival tissue..

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Conclusion It is vivid from the above discussion that the smile we

create should be esthetically appealing and functionally sound too. It is our duty to carefully diagnose, analyze and deliver the best to our patients, taking into account all of the discussed factors.

The aesthetic treatment done by us has to be as conservative as possible unlike the past. Our aim has to be less reduction of tooth structure and greater esthetics and durability. This simply means that cosmetic dentistry has to be a multispecialty branch, wherein all treatments like orthodontics, periodontics, surgical procedures have to be performed whenever deemed necessary.

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References• Aschheim KW, Dale BG. Esthetic Dentistry - A clinical approach to techniques and

materials. 2 nd ed. Missouri: Mosby Publications. 2001. • Bukhary SM, Gill DS, Tredwin CJ, Moles DR. The influence of varying maxillary

lateral incisor dimensions on perceived esthetic smile. Br Dent J 2007;203:687-93.• Rufenacht CR. Principles of Esthetic Integration. Chicago, US : Quintessence

Publishing Co.; 2000. • Andrew Joiner : Tooth colour ; a review of literature. Journal of Dentistry 2004;

32:3-12.• S.M. Burkinshaw. Colour in relation to dentistry. Fundamentals of colour science.

British Dental Journal 2004; 196; 33-41.• Ahmad I : Anterior dental aesthetics : Gingival perspective. British Dental Journal

2005; 199: 195-202.• Sonqvi F, Weisgold AS, Rose LF: Biologic width and its relation to periodontal

biotypes. J. Esthet Dent. 1998; 10: 157-163.

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References• Davis NC. Smile Design. Dent Clin N Am 2007;51:299-318.• Phillips –science of dental materials----11th edition.• Clinical aspects of dental materials –Marcia Gladwin• Textbook of Operative Dentisty-2nd edition-Vimal Sikri

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