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Operative dentistry FIFTH YEAR

Esthetic consideration 26/3/2020

Esthetic Treatment Modalities

The esthetic defects can be corrected by the restorative or non restorative

treatment modalities.

t. Restorative esthetic treatments

Esthetic Treatment Modalities

*■ Direct tooth colored restorations (Layering technique)

Veneers (direct and indirect)

2. Non restorative esthetic treatments

Bleaching

Resin infiltration (ICON) for white spot lesions

Micro and Macro abrasion Selective grinding

(optical illusion)

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ESTHGTIC CONSIDERATIONS

1. Restorative esthetic treatments

a) Layering technique using resin composite (Figure 36):

It is impossible to reproduce the lost tooth structures (enamel and

dentin) with single shade of resin composite

So different shades were introduced to facilitate perfect restoration

of tooth shades and all optical properties

Most of these composites are microfilled ortrue nano composite

The available shades are:

Translucent shades

Almost clear

For creating an incisal edge and proximal line angles Enamel shades

Similar to enamel in translucency and modify the underlying dentin to

obtain the final tooth shade

Dentin shades

- Modify underlying tooth color

- Reduce the transmission of light through the restoration

- Not as opaque as masking agents Body shades

- Its translucency is closer to the enamel shades than to the dentin

shades

- It is used for single shade restorations (without layering)

Opaque shades: (Extra White shades)

It is used to mask the dark discolorations before resin composite

application

If used improperly, it will lighten the shade of the final restoration

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CHAPTER 1

Figure 36: Layering technique

b) Veneers (Figure 37)

They are thin tooth-colored covers of ceramics or resin composite. ♦>

Indications:

1. Gross esthetic derangement as gross discoloration (brown

intrinsic stain, due to dentinogenesis imperfecta or gray stain of

tetracycline).

vitro when calcium hydrovw? e control teeth were * C

the use of this met1 tro evaluation of / '0&:

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urable and protect* stimulation of the e-

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T ted its elative 3 # iwever, dentin sensitivity is s\

Iso reflect on the teehmc 4 K

nicafeyal nation tal effects to ihe p 1 reducing thernu sitivity needs fur* casionally. where _ There is excellent *- ”

y?a Ise3^Ce\ %aersensitivity from nat

-ious forms of fluor iDwyyCr •t/jf/f / c

Topical fluoride m potential to stimul

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2. Loss of translucency (mottled

enamel in fluorosis).

3. Imperfections in contour or surface

texture of upper anterior teeth.

Contraindications:

1. Bruxism

2. Occlusal interference

3. Excessive incisal wears

4. Class III malocclusion because of

the great possibility for dislodgment

Types:

1. Direct Veneers

Direct application of visible light cured resin composite of a

suitable shade.

It is completed in a single chair-side visit.

Sufficient thickness of enamel should be available to provide retention that relies on micro-mechanical bonding.

Technique:

i. Grinding of a part-thickness of enamel.

ii. The incisal reduction should stop just short of the incisal edge to

avoid subjecting the veneer to displacement by functional forces.

iii. The enamel at the periphery of the preparation is beveled for imm

all-round in order to expose fresh and clean enamel of higher

surface energy.

iv. The enamel is acid-etched, washed and dried (etch and rinse

approach)

v. Bonding agent is applied and cured and then the composite is

pressed gently to the preparation, carved, cured, finished and

polished.

Figure 37: Veneer

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CHAPTER 1 2. Indirect Veneers (Figure 38)

• It involves the use of either prefabricated or custom- made resin or

ceramic laminate veneers that are bonded to the surface of the tooth

by resin luting cement.

• Custom-made ceramic or resin composite laminate veneers are

constructed in the laboratory on dies made out of precise rubber base

impressions

Figure 38: Indirect veneers (before and after)

1. Non-restorative esthetic treatments

a. Bleaching:

It depends on oxidization of organic compounds that cause discoloration

of the tooth rendering them colorless and the tooth becomes lighter.

The oxidation-reduction reaction is known as redox reaction. The

oxidizing agent has free radicals with unpaired electrons that are given

to the discolored tooth to become reduced.

■ Types:

I. Extra-coronal or vital bleaching

1. In-office bleaching

2. Home bleaching - - - - - -

Sir

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m W\ eSTHGTIC CONSIDGRATIONS

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II. Intra-coronal ornon-vital bleaching

Techniques: Extra-coronal or vital bleaching:

Vital bleaching techniques include four main categories:

1. Dentist-applied in office techniques

2. Dentist-prescribed/administrated at home techniques

3. Dentist-provided bleaching

4. Over the counter products applied by the patients at home.

1. Dentist-applied in office techniques

The use of a high concentration of hydrogen peroxide (from 30 to

30%) or carbamide peroxide (from 33 to 40%), often supplemented

with a heat source; (power bleaching) using available lamps. The level

of the energy applied is determined according to the patient pain

threshold. Post bleaching the tooth surface should be polished and

sodium fluoride gel is applied for two minutes to reduce post

sensitivity.

This technique is considered as the quickest method of tooth

bleaching, however, it has the disadvantage of the greater expenses

and greater chance of sensitivity with higher concentrations of the

material applied.

Types:

Light-activated bleaching (Figure 39h Light source is applied to the bleaching gel to accelerate the breakdown of H,02 into O and per-hydroxyl free radicals which penetrate into the tooth and oxidize Figure 39: Showing light-activated

chromogens present. bleaching device

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CHAPTGR

Laser-activated bleaching: Argon and carbon dioxide lasers were

cleared by the FDA for use with tooth bleaching. Recently Waterlase is

introduced that seems very successful in tooth whitening.

Ozone-activated bleaching:

It is one of the most powerful oxidizing agents that occurs naturally

and has been recently introduced for bleaching and provides a fast,

effective and harmless method to whiten teeth.

- Ultrasonic-activated bleaching: Ultrasonic energy stimulates a reaction

between other chemicals and the peroxide to enhance the production

of the free radical oxygen atoms without generation of heat.

2. Dentist-prescribed/administrated at home techniques:

By means of a bleaching tray loaded with high concentrations of

carbamide peroxide (from 35 to 40%) that is placed in the patient's

mouth for 30 min to 2 hrs while the patient is in the dental office.

3. Dentist-provided bleaching (Figure 40)

Known as “at-home" or “night-guard” bleaching and administered by the

patient applyingfrom 5 to 22% solution of carbamide peroxide in a

custom-made tray.

Figure 40: Representing Dentist-provided bleaching

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1. Over-the-counter bleaching-

products (Figure 41) often

based on carbamide peroxide

or hydrogen peroxide of

various concentrations and

placed in a pre-fabricated tray,

or by the recently introduced

strips or by patient paint-on, F|gure 4« Representing Over-the-counter

spray or brush-on, all to be bleaching~ Products adjusted

by the user.

II. Intra-coronal or non-vital bleaching:

I

Used for bleaching of non-vital teeth.

Strong oxidizing agents 30-35% aqueous solution of hydrogen

peroxide (superoxole).

- The solution may either be infused through the pulp chamber

into the dentinal tubules, or is made into a paste with powdered

sodium perborate and sealed in the pulp chamber for 3-7 days

(walking bleach).

Post bleaching instructions

1. Restrain from eating, drinking, or smoking. Also, avoid citrus foods

and beverages to minimize discomfort from sensitivity.

2. If sensitivity occurred, cease treatment, and wait 48 hours before

resuming bleaching treatments.

3. Maintain good oral hygiene.

4. Use remineralizing agent.

5. To maintain whiteness, repeat the treatment procedure every four to six

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CHAPTGR 1 b. Resin infiltration (ICON) for white spot lesions (Figures 42-44)

Caries infiltration with Icon fills

the gap between prophylaxis and

filling.

This is highly indicated in white

spot lesions especially after

orthodontic treatment.

In addition, this treatment

optically blends in the lesion with

the healthy enamel.

This innovative method can

therefore be used for esthetic

treatments of front teeth, where

appearance plays an important

role.

The technique involves etching of

the enamel surface by HCI etch

followed by dryness using ethanol

and finally a low viscosity resin

that infiltrate into enamel and fill

the micro-pores then the resin

light cured. This technique inhibits

further demineralization of

enamel and restore the natural

appearance of enamel.

Figure 42: Icon- Infiltrant

PO;

Incipient caries before treatment

Cariogenic acids attack the enamel and draw out minerals. The tooth becomes

porous.

c

After treatment

By sealing the pore system, acids can no longer penetrate into the lesion, thus

stopping the progression of the caries

Figure 43: Prevention of further deminer-

alization of enamel after ICON treatment

Figure 44: Case before and after ICON

application

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ESTHETIC CONSIDERATIONS

c. Micro and Macro abrasion

Both micro-and macro-mechanical abrasion may be employed for

elimination of superficial discoloration defects that are limited to the

outer o.2-0.3 mm of enamel surface e.g. superficial fluorosis.

1. Micro-mechanical abrasion (Figure 45)

- Involves polishing tooth surface with a paste of pumice and 10%

hydrochloric acid for 5 seconds per application.

- A minimum of 11% of enamel thickness is removed in each application.

Figure 45: Micro-mechanical abrasion

2. Macro-mechanical abrasion (Figure 46)

Involves use of fine diamond point to remove discolorations.

A water-air spray is used to cleanse the area and to cool the tooth.

Figure 46: Macro-mechanical abrasion

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CHAPTER

d. Selective grinding (Figure 47-53)

Reshaping of natural teeth by

grinding them with diamond tools

and polishing with fine sand paper

disks for cases that require removal

of only part of enamel thickness.

■ Indications:

1. Crowded, mal-posed, and

super-erupted teeth

2. Eliminate minor mismatch in Figure 47: Vertical and horizontal lines

tooth form

Cervical transitional line angle

Mesial transitional line angle

■'wm

Distal transitional line angle

«««*

Incisal transitional line angle

3. Establish symmetry

4. Provide better esthetics

without any considerable

cutting of tooth substance

or material application

Principles of Illusion

Several basic principles of illusion,

such as those used to describe form,

light, shadow, and line, may be

applied specifically to dentistry.

In the presence of excess light or in

the absence of light, form cannot be

distinguished since shadows are

necessary to help make perceptible

the contour or curvature of a surface

and depth.

The basic principles of illusion concerning shape and outline form are:

1. Vertical lines accentuate height and de-emphasize width.

2. Horizontal lines accentuate width and de-emphasize height.

3. Shadows add depth. 4. Angles influence the perception of intersecting lines.

Figure 48: The face of the tooth is bound

by the transitional line angles

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eSTHGTIC CONSIDERATIONS

Figure 49: Creating

illusions of width. A,

Normal width. B, A tooth

can be made to appear

narrower by positioning

mesial and distal line

angles closer together. C,

A tooth can be made to

appear wider by

positioning mesial and

distal line angles away

from each other.

Normal Narrowing Widening

5. Curved lines and surfaces are

softer, more pleasing, and

perceived as more feminine

than sharp angles.

6. The relationship of objects

helps determine appearances.

Figure 50: Mesial and distal transitional line

angles

Examples:

1. Rounding of sharp edges of incisors resulted from excessive attrition.

2. Squaring of angles and straightening of incisal edges of maxillary

incisors to create masculine character

3. Rounding of angles, opening of the embrasures of maxillary incisors

and slight shortening of laterals to create feminine characters

4. Minimum flattening or rounding the labial surfaces of maxillary

incisors to give illusive appearance of wider or narrower surfaces

respectively

5.

6.

Slight shortening of an incisor to be symmetrical with an adjacent one

with a slight edge fracture

Rounding of cusp tip of cuspids occupying positions of missing lateral

incisor

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CHAPTER

Lengthening Shortening Normal

Figure 51: Illusion of length

Contraindications:

If it is ineffective or create

occlusal disharmony

If it is unacceptable to patient

Insufficient enamel thickness

Compromise the resistance of

enamel to fracture or wear

Cause pulp or periodontal

problems

Cases requiring major

orthodontic treatment

Tooth hypersensitivity

Teeth with large pulp

chambers

Deep discoloration

Presence of large anterior

restorations

Figure 52: The central incisors appear

longer, enhancing the illusion of

narrowness

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Figure 53: Incisal angles roundation more

palatally and widening incisal embrasure

creating illusion of narrower tooth