Operative dentistry Fifth year Esthetic consideration 16/3/2020

Definition of Esthetics

According to Dr. Ronald E. Goldstein

(Figure 1), “Esthetic dentistry is the art of

dentistry in its purest form.”

According to the American Academy of

Cosmetic Dentistry, the cosmetic dentistry

is dedicated to the art and science of

enhancing a person's smile and overall

appearance.

According to Webster's New International

Dictionary defines “aesthetic” as “appreciative of and responsive to

the sense of beauty or fine culture”

Smile Design is defined as:

The planning and pre-visualization of the desired end result of an esthetic

dental treatment targeting a more harmonious state instead of the current

disharmony, according to rules of facial, dental and gingival harmony as well

as to the patient's demands.

The sequences of smile design are:

1) Proper analysis including:

Facial analysis

Labial analysis

Gingival analysis

Dental analysis

2) Design of new smile

Figure i: Dr. Ronald E. Goldstein

Facial Analysis

The facial morphology is important factor for determination of the tooth

morphology.

The basic shape of the face when viewed from the frontal aspect can be

one of the following (Figure 2,3):

1. Square

3. Square tapering

2. Tapering

4. Ovoid

SQUARE SQUARE TAPERING TAPERING OVAL

Figure 2: The basic shape of the face when viewed from the frontal aspect

Oval Oblong Round Rectangular/ Long

Square Triangular Inverted Triangle/ Diamond Heart

issa

Figure 3: The frontal aspect of the face shape

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An individual lateral profile (Figure 4):

1. Straight

2. Convex

3. Concave

Concave

Facial Midline (Figure 5): Figure 4: An individual lateral profile

A line is drawn between the nasion and the

base of the philtrum.

• Whenever possible the midline between

the maxillary central incisors should be

coincidental with the facial midline. In

cases in which this is not possible, the

midline between the central incisors

should be parallel to the facial midline.

Interpupillary line (Figure 5):

The interpupillary line should be

perpendicular to the midline of the face and

parallel to the incisal plane.

Facial Thirds

Horizontal proportions (Figure 6):

• Rule of fifth: the width of the face should

be the width of five “eyes”. Figure 6: Horizontal dimensions

Convex

I

Concave Plane

Figure 5: Relaxed mouth opening

display facial midline, interpupillary

line and commissural/incisal line

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Vertical proportions (Figure 7):

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 one third 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.

Figure 7: Vertical dimensions

Naso-Labial Angle (Figure 8):

• Formed by intersection of two lines (one

tangent to the base of the nose and one

to the upper vermillion border of the lip)

at subnasale.

• The angle ranges generally from 85° to

105°.

Figure 8: Naso-labial angle

Ricketts* E-plane (Figure 9):

• A line that extends from the tip of the

nose to the chin

• The maxillary and mandibular lip

positions are away by 4 and 2 mm,

respectively from this plane (an important

reference for esthetic lip position).

Figure 9: Rickett's E-plane

VAA % ft.

. % 'yrn

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Labial Analysis Lip morphology (Figure 10-13):

1. Medium lips

Figure 10: Medium lip

2. Flat lips

Figure 11: Flat lip

3. Thin lips

Figure 12: Thin lip

4- Thick or Full lips

Figure 13: Full lip

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Lip Line (Figure 14):

Lip line should not be confused

with the smile line.

• Refers to the position of the

inferior border of the upper

lip during smiling

• Determines the display of

tooth or gingiva at this hard

and soft tissue interface.

• Under ideal conditions, the

gingival margin and the lip

line should be congruent

or there can be a 1-2 mm

display of the gingival tissue.

It may be either:

1. Low lip line: showing only

the edges of upper front

teeth.

2. High lip line: showing part of

their labial gingival tissues.

3. Reversed:

showing the

lower teeth.

N.B: “Gummy smile” resulted from High lip line (Figure 15) together

with short clinical crowns may

cause exposure of excessive

amounts (3-4 mm or more) of

gingiva on smiling or during

conversation. It often requires

cosmetic periodontal recontouring

to achieve an ideal result. Figure 15: High lip line (Gummy Smile)

High lip line

Reversed lip line

Figure 14: Different lip lines

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CHAPTER

Gingival Analysis

1 Gingival level and harmony

- Establishing the correct gingival levels for each individual tooth is the

key in the creation of harmonious smile.

- The cervical gingival height (position or level) of the centrals should be

symmetrical. It can also match that of the canines. It is acceptable for the

laterals to display the same gingival level.

- The gingival margin of the lateral incisor is o.5-2.0 mm below that of the

central incisors. The least desirable gingival placement over the laterals is

for it to be apical to that of the centrals and or the canines.

Gingival Zenith (Figure 16) v:

• It is highest point of the gingival margin

• Zenith of the laterals -* on midline

• Zenith of centrals and canines distal to midline

Figure 16: Zenith Points

Gingival symmetry (Figure 17):

For maximum esthetic it is

preferable for the gingiva to be

symmetrical

Figure 17: Gingival symmetry

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Gingival hypertrophy (Figure 18):

The increased sized gingiva can be treated by Gingivectomy either surgically

or by laser.

Figure 18: Gingival hypertrophy: (a) before treatment, (b) after treatment

Gingival recession (Figure 19):

The best line of treatment is soft tissue grafting

Figure 19: Gingival recession (before and after treatment)

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CHAPTER 1 Dental Analysis

Teeth size, proportions and position

Central dominance (Figure 20):

The centrals are the key to the

smile. They must be the dominant

teeth in the smile and they must

display pleasing proportions.

The width to length ratio of the

centrals should be approximately

of 75-80%, which is considered the Figure 20: Central Dominance

most acceptable.

Dental Proportion Guidelines

1. Golden proportion (Lombardi),

2. Recurring esthetic dental proportions “RED” (Ward),

These proportions are based on when viewed from the facial aspect.

The distance between proximal line angles of the teeth (the perceived

size) and not the actual size.

t. Principle of Golden Ratio (Golden proportion, Lombardi) (Figure 21):

• When viewed from the facial, the width of each anterior tooth is 60% of

the width of the adjacent tooth (mathematical ratio being 1.6:1:0.6).

Figure 21: Golden proportion (Lombardi)

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ESTHETIC CONSIDERATIONS W

Patients have different arch form, lip anatomy and facial proportions

so it is difficult to apply.

Golden proportion calculations may lead to cosmetic failure due to

the limitation of creativity.

2. Recurring esthetic dental proportion “RED” (Ward) (Figure 22):

• When viewed from the facial aspect: As we move posteriorly form

midline, the successive width proportion should remain constant.

• This offers great flexibility to match tooth properties with facial

proportions.

Different Height Teeth with

Appropriate RED Proportions

short teeth

normal

length

tall teeth

TOQCQ

rax Consistent 78% w/1 ratio of

central incisor

80% RED

70 % RED

62% RED Golden Proportion

RED Proportion

y

=constant

x -v

XI

Figure 22: Recurring esthetic dental proportion (RED)

Smile Arc (Line) (Figure 23):

• An imaginary line along the

incisal edges of the maxillary

anterior teeth that mimic the

curvature of the superior

border of the lower lip while

smiling.

Figure 23: Smile arc (line) When the centrals appear

shorter than the canines

along the incisal plane (Reverse smile line or inverse smile line)

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CHAPTER 1 Dental midline (Figure 24,25):

• It should be:

1. Parallel to the long axis of the face

2. Perpendicular to the incisal plane

3. Over the papilla (drop straight down from the papilla).

• Minor discrepancies between facial and dental midlines are acceptable

and, in many instances, not noticeable.

• The maximum allowed discrepancy :

2 mm and sometimes greater than 2 mm discrepancy is esthetically

acceptable as long as the dental midline is perpendicular to the

interpupillary line.

Figure 24: Dental Midline

Buccal Corridor (Figure 26)

• A dark space (negative space)

that is visible between the corners

of the mouth and the buccal

surfaces of the maxillary teeth

during smiling.

• Its appearance is influenced by

1. The width of the smile and the

maxillary arch

Figure 25: Dental midline coinciding with

the long axis of the face

Figure 26: a) Insufficiently developed

buccal corridor, b) properly developed

buccal corridor (The European Journal of

Orthodontics: 33 (4))

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1. The tone of the facial muscles,

2. The positioning of the labial surface of the upper premolars,

• The buccal corridor is directly influenced by the arch form.

• A narrow arch is generally unattractive. The unattractive, negative space

should be kept to a minimum. To solve or minimize this problem, the

premolars can be restored.

Axial Inclination (Figure 28):

• There should be natural, progressive increase in the mesial inclination

of each subsequent anterior tooth (from the central to the canine)

(Least noticeable with the

centrals and more pronounced

with the laterals and slightly

more so with the canines).

• The evaluation

of axial

inclination can be done on a Figure 28: Axial inclination

photograph of the anterior teeth

in a frontal view.

Display Zone and Teeth Visibility (Figure 27)

• In a young individual (when the

mouth is relaxed and slightly

open): 3.5mm of the incisal third

of the maxillary central incisor

should be visible.

• As age increases:

Less tooth display due to the

decline in the muscle tonus FiSure 27: lmaSe of the lower one third showing tooth display at rest

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1

CHAPTER]! -

Incisal Embrasures (Figure 29);

The incisal embrasures should display a natural, progressive increase in size or

depth from the central to the canine.

As a rule, a tooth distal to incisal corner is more rounded than its mesio incisal

corner.

Figure 29: Incisal Embrasures

Interproximal contact point (ICP) (Figure 30):

• It is the most incisal aspect if

the Interproximal contact area

(ICA).

• As a general rule, the ICP moves

apically, the further posterior

one moves from the midline.

Figure 30: Interproximal contact points

Incisal edge positioning (Figure 31): is determined by:

• Vermillion border of the lower

lip

• Phonetics

• Parallel to interpupillary line

Figure 31: Incisal edge positioning

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Surface Texture and Luster (Figure 32):

It refers to the degree of

smoothness vs. roughness that

occurs on the tooth's surface.

Sex, age and personality

(Figure 33):

Minor differences in the length, shape and positioning of the

maxillary teeth allow for dramatic

characterization.

• 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

Figure 33: Characterization (sex, age and

personality) Lombardi matrix

Figure 32: Micro and macro surface texture

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CHAPTER 1 Position and alignment (Figure 34):

Teeth should be aligned in harmony.

The smile can be analyzed at rest (M-position) or smile (E-position).

Figure 34: Teeth alignment before and after orthodontic treatment

In the M-position, the following references are measured and analysed:

commissure height; philtrum height; and visibility of the maxillary incisors.

• By having the patient says the letter “M” repetitively and then allow her/

his lips to part gently, the dentist can be able to assess minimum tooth

reveal.

• Younger patients may show between 2-4 mm of maxillary incisal

edge in this position.

• As people age, the maxillary incisal edge reveal shrinks and even

disappears.

In E-position (Figure 35) the following references should be analysed:

smile arc (line); dental midline;

smile symmetry; buccal corridor;

display zone and teeth visibility;

smile index; and lip line.

• When patients say the letter

“E” in an uninhibited and

exaggerated way, the dentist

can ascertain the maximum extension of the lips. Figure 35: E-position

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Teeth shade

Color perception:

When the light bands reflected from the tooth, strike the eye, energy ->

stimulates the photoreceptor{rods and cones} in the retina -> photo-

chemical reaction -> neural impulses^ brain-* excite the perception of a

given color. The rod cells are responsible for brightness of color (value)

while the cone cells are responsible for hue and Chroma.

Factors affecting optical qualities of an object as seen by an observer's eye:

1. Spectral characteristics of the light source

2. The spectral characteristics of the object

3. Sensitivity of the observer eye

1. Spectral characteristics of the light source:

■ These are: the angle between the observing eyes and the object,

interface of the object and incident light rays, intensity of light and

type of light.

■ Metamerism: Color, transluc^ncy and surface texture of the same

object appear different under different light sources therefore; color

determination of teeth must be done under neutral illumination i.e.

light having no dominance of a specific color.

2. The spectral characteristics of the object:

■ These are: surface reflectivity, refractive index, homogeneity, light

absorption and light scattering.

3. Sensitivity of the observer eye:

■ Including: the eye sensitivity lo light, color vision and blindness,

optical illusion and color fatigue.

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CHAPTER

Requirements for correct color determination

■ The illuminant should be neutral.

■ The background should be neutral orgray to eliminate dominance of

particular colors.

■ The background involves wetness of the tooth, office curtains, walls,

and we should remove any lipstick and make-up before color

determination.

■ Patient position: color selection is preferably made with patient

seated at the same level relative to the observer's eye.

Measurement of color Methods of shade selection in dentistry

Color determination in dentistry can be divided into two categories:

• Subjective technique (Visual technique)

- Shade guide

• Objective technique (Instrumental technique)

A. Spectrophotometer

B. Colorimeter

C. Digital cameras and imaging systems

Type of measurements used in digital shade selection

Digital shade selection is based on two types of measurements namely spot

measurement and complete tooth measurements.

Spot measurement

Devices based on this principle measure a small area of tooth surface.

Since diameter of the optical device is less, it cannot deliver all the

information necessary to create a whole image of tooth.

Spot measurement device generally require three points of reference on a

tooth surface.

Examples of spot measurement devices are Vident Easy Shade Compact

system and X-rite Shade-X.

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Complete tooth measurement

These digital systems measure entire tooth surface, thus providing a

complete shade mapping of tooth.

Because of the size of the sensor, their use is limited to anterior teeth.

Examples of these devices are the MHT Spectro Shade and the Olympus Crystal Eye

Digital Smile Design • The Digital Smile Design (DSD) is a multi-use conceptual tool that can

strengthen diagnostic vision, improve communication, and enhance

predictability throughout treatment.

• The DSD allows for careful analysis of the patient's facial and dental

characteristics along with any critical factors that may have been

overlooked during clinical, photographic, or diagnostic cast-based

evaluation procedures.

• DSD sketches can be performed in presentation software such as

Keynote (iWork, Apple, Cupertino, California, USA) or Microsoft

PowerPoint (Microsoft Office, Microsoft, Redmond, Washington, USA).

• This improved visualization makes it easier to select the ideal restorative

technique.

• The DSD protocol is characterized by effective communication between

the interdisciplinary dental team, including the dental technician. Team

members can identify and highlight discrepancies in soft or hard tissue

morphology and discuss the best available solutions using the amplified

images.

• Every team member can add information directly on the slides in writing

or using voice-over, thus simplifying the process even more.

• All team members can access this information whenever necessary to

review, alter, or add elements during the diagnostic and treatment

phases.

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CHAPTER 1 SOLVING ESTHETIC PROBLEMS

Causes of Esthetics Defects

1. Caries: loss of tooth substance and if the pulp is involved, the

translucency of the tooth will be changed.

2. Occlusal disharmony of teeth e.g. drifting, crowding or diastema.

3. Loss of tooth substance due to traumatic fracture, erosion, attrition or

abrasion.

4. Discoloration (intrinsic or extrinsic) that may be a result of drug therapy

(tetracycline), congenital anomalies (fluorosis), loss of pulp vitality,

caries and discolored restorations.

5. Minor abnormalities in size and shape of teeth e.g. (pig-shaped teeth).

6. Missing teeth due to extraction, trauma, or congenital anomalies.