ESTHETIC CONSIDERATIONS - University of Babylon

ESTHETIC CONSIDERATIONS

Smiling in the face of your brother

Are “ charity ”((Prophet Mohamed))

Does beauty really come from the inside out or does your physical appearance play the greater role?

Do we really think beauty is only skin deep or are our brains hard wired to think otherwise?

What is beauty?

The secret of beauty and attractiveness has been a quest of humans for as long as we have been civilized

Many women – even some men - spend up to one-third of their income on improving their looks

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Is that portion of the discipline that deals with achieving theultimate in appearance, escape from artificiality.

EstheticBranch of philosophy dealing with beauty.

The branch of philosophy dealing with beauty. In dentistry, the theory and philosophy that deal with beauty and beautiful, 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:Art and science of dentistry applied to create or enhance the beauty of an individual within functional and physiological limits. The application of the principles of esthetics to the natural or artificial teeth and restorations.

Esthetic dentistry is characterized primarily by the smile. The goal in the creation of esthetic dental restorations is to stimulate, or improve upon, the appearance of the natural dentition. The successful esthetic restorations must integrate harmoniously with the whole of the face., not just with the surrounding teeth.

Smile:is the ability of person to express a range of emotions with thestructure and movement of the teeth and lips can often determinehow well a person can function in society. the perceiveness of one’spersonality is said to be a God’s gift. Certain issues might creatediscrepancies in this appearance, the role of a cosmetic dentist iscrucial in analyzing and crafting the desired smile.

Appearance Zone :This is the anterior oral area where esthetics is of prime concern and which is visible on smiling, from maxillary premolar to premolar (usually 1st molars also).

Depends on the person’s self-image, mouth size, teeth size, smile width, lip size and tightness.

Esthetic reshaping:Modification of the surfaces of teeth to improve appearance.

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.

Smile designing:Is a process whereby 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. These changes are governed by the principles of esthetic dentistry.

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.

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

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

Factors Affecting Esthetics

1- SOFT TISSUE MANAGEMENTA-FINISH LINE FORMATION.B-IMP RESSION PROCEDUR.C - THE TEMPORARY RESTORATION.

2- TOOTH REDUCTION

3- SHADE SELECTION

4 - COLOR VARIATION

9- OPTICAL ILLUSON

8-TOOTH FORM,SIZE AND ARCH POSITION

7- DEGREE OF GLOSS

6- SURFACE CHARACTERIZATION5-TRANSLUCENCY

1- SOFT TISSUE MANAGEMENT

Optimal soft tissue health should be established before any restorative procedures.

Many aspects of prosthetic treatment may cause esthetically detrimental changes in theform of changes in gingival form ,color or position following cementation.

A- Finish line formationWith subgingival margins ….. every effort must be made to produce minimal soft tissueinjury .

Retraction Cord Technique-The preparation is completely established - with a suprra-gingival finish line.

-Then a retraction cord is placed in the sulcus and temporarily displace the gingiva laterally and apically

-Excessive instrument pressure exerted in placing the excessively large cords----gingival damage.

-Single medium-sized ------------- posterior teeth.

-Too large or too many cords --------- excessive trauma.

-Finally, the finish line can be lowered without soft tissue injury.

-Healthy gingival tissue, one thin cord -------- anterior teeth

-Blanching (evidence of reduced blood supply) is often observed immediately after placement of cord rapidly disappears.

An impression must provide detailed information about :The prepared teeth, Surrounding intact teeth, Associated soft tissues

B-Impression Procedure:

-Remove all cord from the sulcus as the impression material is syringed around the prepared teeth.

-Removal of the impression from the mouth, then check the gingival sulcus with an explorer and remove any remnants of retained impression material.-Severe tissue reactions when the impression material is left in the sulcus.

Inadequate soft-tissue management

Causes of finish line not visible in the impression:

Bleeding from inflamed gingiva displacing the impression material

Tendency of the gingival cuff to recoil and displace partially set impression material

because of inadequate bulk Sulcus impression tearing

Retraction cord

Two-cord technique

Rotary curettage

Electrosurgery Laser troughing

C - THE TEMPORARY RESTORATION

1-Properly contoured

2-Well adapted to the preparation margin

3-Should possess a very smooth surface

4-Establish cervical embrasures to provide access for oral hygiene aids

5-Left not more than two to three weeks

10-An over contoured embrasure will reduce the space intended for the gingival papilla and causing pressure and irritation on the papilla, also inhibits effective oral hygiene

9-Open embrasures to allow easy access to the interproximal area for plaque control.

8-Crown contours should be such that it should not provide any niche for plaque retention and should promote self-cleaning.

7-Interdental papilla is often neglected due to improper design of interdental space.

6-Overcontouring leads to food trap and hence complicating the periodontal status.

laceration of the gingiva with rotary instruments + poor temporary restoration.

Final restoration …………… fails to vertically reach the finish line of the prepared tooth

Overextended or under extended restoration

plaque accumulation at the margin of the restoration.

A uniform duplication of the form and contours of the natural dentition.

2- TOOTH REDUCTION

Insufficient tooth reduction poor esthetics

Development of adequate color requires a certain thickness of porcelain

The facial reduction should be 1 to 1.5 mm.

The areas to be considered during preparation :

1- labioincisal aspects.

2- Cervical portion of the facial surface.

A) The facial surface should be reduced in two planes; one nearly parallel with the path of insertion, and one parallel with the incisal two-thirds of the facial surface of the tooth

C) One plane reduction which creates adequate space for the restoration both in the shoulder and the incisal areas, will endanger the pulp entity and produce overtapered restoration.

B) One plane reduction parallel with the path of insertion may result in insufficient space for porcelain in the incisal 1/3 of the tooth

inadequate facial reduction, the laboratory fabrication can be handled in one of two ways

1- develop proper contour in the restoration, results in a lack of color vitality due to insufficient porcelain thickness: External and internal color modification to enhance the esthetics of the restoration.

2- over-contoured restoration to develop proper color leading to plaque accumulation which affects the gingival health.

3- SHADE SELECTION

Shade interpretation

Difficulty in color matching …precise matching of a desired shade can be difficult.

The original color of a tooth is the color one sees as a result of the reflection, refraction, deflection, and absorption of light by the enamel, the dentin, and possibly the pulp.

The color seen in a tooth is the result of combined optical effects of the layers of tooth structure, the translucency and thickness of the enamel and color of the underlying dentin.

The esthetic dentistry, using a combination of science and art, involves the use of colors to create a natural tooth like restoration, color and shade are very important because teeth are multi-chromatic with color variations from cervical to incisal, every tooth in the mouth from the central incisors to molars, both upper and lower, varies in color.

Color:Dimensions of color:Color cannot be perceived without light, which is a form of electro-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.

Color that is perceived is the result of a light source, the object that absorbs, transmits, reflects or scatters the light from the source, and the interpretation of the result by the human visual system

Light form of visible energy that is part of the radiant energy spectrum. Radiant energy possesses specific wavelengths, which may be used to identify the type of energy

In 1666 Isaac Newton discovered that white light can be broken down into a rainbow of color

In nineteenth century that German physiologist Ewald Hering first described the now familiar color circle.

In 1905, Albert Henry Munsell, an American artist and art teacher, further modified the color circle, devising a system of color organization that centered around three unique aspects of color: hue, chroma, and value. Using these three aspects, was able to construct a three-dimensional color wheel

Color Mixing

Light mixture- primary colors: red, green, blue.

Additive mixture system- mixingof two of the light mixture primary colors

red + blue = magentared + green = yellowgreen + blue = cyan

Pigment mixture system: yellow, cyan, magenta

Color of the Human TeethClark was the first to accurately describe the color of the human teeth in 1931

Dr. E. B. Clark, a dentist, produced the first data in 1931.He indicated the Hue ranged from 6 YR (yellow-red) to 9.3 Y (yellow).The Value ranged from 4 to 8, and the Chroma ranged from 0 to 7.Clark stated that “Color, like form, has three dimensions”.

Lemire and Burk found:The Hue range from 8.9 Y to 3.3 Y, a Value range of 5.8 to 8, and a Chroma range from 0.8 to 3.4

Goodkind and Schwabacher:Identified the Hue range as 4.5 YR to 2.6 Y, the Value range as 5.7 to 8.5, and the Chroma range from 1.1 to 5.

Guidelines for Clinical Shade Selection1.light

2.amount lighting

3.location of lighting

4.restricting light

5.surrounding colors

6.tone of selection

7.patient position

8.tooth condition

9.comparison prcds.

10.selectiodistance

11.verification

12.diagram

13.photograph

Vita 3D stapes 1 (Value)

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.

Munsell color system extends from zero to ten, black is zero and white is ten

Vita 3D stapes 1 (Value)

1-Determine the lightness level (value)

2-Hold shade guide to patient’s mouth

3-Start with darkest group moving right to left4-Select Value group 1, 2, 3, 4, or 5

Vita 3D stapes 2 (Chroma)

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.

Vita 3D stapes 2 (Chroma)

Select the chroma

1-From your selected Value group, remove the middle tab (M) and spread the samples out like a fan.

2-Select one of the three shade samples to determine chroma.

Vita 3D stapes 3 (Hue)

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.

Vita 3D stapes 3 (Hue)

Determine the hue

Check whether the natural tooth is more yellowish or more reddish than the shade ample selected

Shade matching using the VITA Easyshade Compact:

1-“Tooth areas” mode selected. Note the active dot appearing in

the cervical third of the tooth on the screen.

2-Wand tip on the buccal surface at the cervical third of the tooth.

3-“OK” signal in the cervical third and active dot in the middle

third on the screen.

4-Wand tip on the buccal surface at the middle third of the tooth.

5- OK signal in the cervical and middle thirds and active dot in the

incisal third on the screen.

6-Wand tip on the buccal surface at the incisal third of the tooth.

7- OK signal in the cervical, middle, and incisal thirds on the

screen.

8-VITAPAN Classical and VITAPAN 3D-Master shades that are

closest to the natural tooth structure color shown on screen.

Note: The nonslip infection-control shield has been omitted from

this series of photos for demonstration clarity.

Color research continued to evolve based on the Munsell color model.In 1976, The Commission Internationale de l’Eclairage (CIE), an international color research group founded in 1931, published the CIELAB color system.

CIELAB COLOR SYSTEM

In this 3-dimensional color system, L* refers to brightness (0 to 100), a* represents red (+a*) vs. green (-a*) and b* indicates yellow (+b*) vs. blue (-b*). When a* and b* are zero, the L value represents the continuum of black to white.

The CIELAB model offers some advantages over other color models. The L*a*b* color space was designed to correlate with perceptions of color.

Color Differences CIELAB

Is often used to measure changes in color, including changes in tooth color from use of whitening products. Color difference equations are used to quantify the color change. ΔL*, the change in brightness,

Factors can be responsible for poor color matching

1-A poor selection may have been made from available shades, or it may not be possible to match the natural teeth with the available porcelain colors.

2. The dental laboratory may have failed to reproduce the selected shade from the available materials or there may have been insufficient information to effect a satisfactory color modification.

4. Also, the porcelain may not have been handled in such a manner as to reveal its inherent coloration.

3. The tooth reduction is insufficient in certain areas, or the metal framework or opaque porcelain, or both, may be too thick, leaving insufficient space for dentin porcelain.

COLOR VARIATIONS AMONG TEETH

Cervically : dentin is more than enamel.Incisally the enamel is thicker than the dentin, which increases the translucency.

1- Maxillary anterior teeth

canines pigments related to the dentine thickness.

.lateral incisor slightly less pigmentation than the central incisor, related to the facio-lingual dentine thickness, which is often slightly less on a maxillary lateral incisor.

The canines exhibit the greatest color intensity, with the incisors usually appearing the same.

If a variation in the incisors exists, it is the opposite of that found in the maxillary incisors.

The lateral incisor pigmentation owing to the larger crown dimension.

Mandibular anterior teeth :

Staining

Not only used to duplicate the natural variation of the tooth color, but also to create and enhance illusion through manipulation of shape.

Darker stains optical illusion of smaller size

Increasing the value ( increase whiteness) closer area

Decreasing the value(increase grayness) less prominent area