Esthetics / orthodontic courses by Indian dental academy

INTRODUCTION

An acceptable cosmetic effect in any dental restoration has always been

regarded as important to good dentistry. A well-made prosthesis will fail if it is

deficient in this respect.

Esthetics includes the appreciation and response to the beautiful in art

and nature. Esthetics has been given many definitions in dentistry but

according to Young. “It is apparent that beauty, harmony, naturalness and

individuality are major qualities” of esthetics. The dentist must visualize

esthetics in relation to the patient and then translate that visualization into an

acceptable esthetic result. The success of his efforts depends upon his artistic

ability, his powers of observation and his experience.

The selection of anterior teeth for an edentulous patient is a most

important and often difficult problem for the dentist. He should select teeth

which not only embody the proper form and size, but the most ideal shade as

well.

The art of selection of teeth for edentulous patients has been lost in the

maze of tooth guides, folders and pamphlets and the numerous methods of

selection advocated by researchers.

An attempt has been made in this seminar to briefly describe the various

methods advocated in the literature and to reach a practical method.

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For the sake of clarity and simplicity, the matter has been dealt with

under the following sub headings.

- Introduction

- Review of Literature

o Evolution of Techniques

o Dentogenics

o The Golden Proportion

- Discussion

- Conclusion

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REVIEW OF LITERATURE

I) Evolution of Techniques

Young in 1954 described the evolution of various techniques used in the

selection of the anterior tooth mold.

Technique 1

During the ivory age and early porcelain period, teeth were selected or

created mostly by dimensional measurements of the denture space and arch

size with little regard to esthetics.

Technique 2

Technique of ‘Correspondence and Harmony’ projected by J.W. White

in 1872. By this time, the temperamental theory was fading out of medicine but

white reached over and suggested that the temperaments called for similarity of

form in faces and teeth.

The temperamental theory is a theory of the fluids of the body,

especially the blood, the phlegm and the bile. It was conceived by Hippocrates

in the 5th century BC and was used continuously by the medical profession in

diagnosis and treatment until the nineteenth century, when it gave way to

demonstrate science.

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Choleric temperament – predominance of yellow bile characterized by anger,

irritability, a jaundiced view of life. Body structures are small and finely

textured.

Melancholic – due to predominance of black bile and characterized by

depression.

Phlegmatic temperament – due to abundance of phlegm in respiratory passages.

Alleged to make people stolid, apathetic and undemonstrative. A physical

decline occurs due to phlegm in the blood.

Sanguine temperament – attributed to a predominance of blood and

characterized by cheerfulness and optimism. Red complexion, large body,

strong musculature and vigorous action.

This was the introduction of the temperamental theory into dentistry –

but it was not widely used till after 1885 when temperamental forms of teeth

were manufactured as “named sets”.

Technique 3

The “Typical form” concept projected by W.R. Hall in 1887. This was

the initiation of the geometric theory later presented by Williams.

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The basis of this classification was two-fold, the major basis was the

tooth’s labial surface curvatures (transverse and gingivo-incisal), outline form

and neck width.

Hall gave the classification of overall tapering and square.

The minor basis was the labio-lingual inclination of the upper incisors in

relation to profile types. This classification apparently exerted little influence

on practice procedure at that time.

Technique 4

The “temperamental technique” was the first technique of selecting

tooth form from the point of view of influence and universal acceptance. It

required several years to associate and establish dental characteristics of the

temperaments and to incorporate them in manufactured tooth forms, this

occurred by 1885.

Dentists like Flagg, Laycock, Hutchinson, Kingsley et al and artists like

Madame Schimmelpeinik, spurzheim and Jacques contributed to the

development and acceptance of this theory.

However, only rarely could two dentists agree on exactly what the

theory meant, what it taught and what it required. It had an intangible quality

which could not be defined in any authoritative way.

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Technique 5

Berry’s biometric ratio method – 1906.

Berry projected in 1903 that the outline form of the inverted central

incisor tooth closely approximated the outline form of the face. Therefore the

outline form of the edentulous face indicated the outline form of the anterior

teeth to be chosen for a denture patient.

Berry’s continued investigation into the correlation between faceform

and tooth form resulted in the discovery that the maxillary central incisor was

1/16th the width of the face and 1/20th its length. Subsequent research by M.M.

House and others proved the 1/16th width ratio but the 1/20th length ratio which

was frequently not possible to use due to interference by ridge bulk. Difficulty

in practical applications discouraged the use of this technique.

Mavroskoufis et al in 1981 concluded that the inter-alar nasal width is a

reliable guide for selecting the mold of anterior teeth. The tips of the canines

were found to lie on a projection of two perpendicular lines drawn from the

outer surfaces of the nasal alae.

Thus the mesiodistal width of the artificial anterior teeth should be

determined by adding 7mm to the patient’s nasal width.

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They found no relationship between the nasal width and the total/overall

width of the four incisors.

The authors advocate that the tips of the canine be set on a line which

passes through the posterior border of the incisive papilla which proved to be a

stable anatomic land mark.

The incisive papilla can also be used as a guide for arranging the labial

surface of the central incisors at 10mm anterior to the posterior border of the

papilla.

Kern in 1967 studied various anthropometric parameters of tooth

selection by examining over 6000 skulls. He concluded that:

1. The bizygomatic measurement did not show a high percentage

consistency ratio to the width of the crowns of the maxillary central

incisors.

2. Nor did the skull length measurement prove reliable for the

determination of the length of the maxillary central incisor crown.

Significantly consistent ratios were found to occur in:

1. The nasiomenton (internasal and nasofrontal sutures and the chin)

measurement and the length of the maxillary central incisor crown

showed a 11:1 ratio in 81 per cent of skulls. However this has little

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significance in edentulous patients whose nasiomenton measurements

depends on the degree of mouth opening and the orientation of the

occlusal plane.

2. The cranial circumference and the widths of the maxillary anteriors

showed a ratio of 10:1 in 91 percent of skulls. This has been reported by

Sears also.

3. 93% of skull showed equal or near equal measurements between the

nasal widths, nasal aperture and the width of the four maxillary incisors.

4. The maxillary and mandibular anterior teeth showed a high percentage

ratio of 5:4 in 90% of skulls. Sears also reported similar findings.

Technique 6

“Clapp’s tabular dimension table method” – 1910.

Teeth were selected based on the overall dimension of six anterior teeth

arranged on the Bonwill circle and the vertical tooth space available in the

patient.

A table with illustrations of molds allowed the dentist to select and

specify the mold to be used by number.

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Technique 7

Valderrama’s “Molar tooth Basis” was projected in 1913. This method

of only historical value used varying measurements between combinations of

cusp points to indicate the size of the individual and overall tooth

measurements. The basic problem with this technique is that edentulous

patients have no molars.

Valderrama also predicted a selection of tooth size on a 1/4 th increment

of the size of a Bonwill triangle, determined by measuring the edentulous

mandible.

Technique 8

Cigrande 1913 advocated the use of the outline form of the fingernail to

select the outline form of the upper central incisor. The size was modified to

meet the requirements of tooth space and other relationships.

Technique 9

The Geometric method or Law of Harmony.

William’s “Typal form method” projected by J. Leon Williams in 1914

is based on the geometric pattern created by the outline form of the bony face

frame – the ovoid, square and tapering forms. William arrived at this

classification after extensive anthropological study and was able to interest a

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manufacturer. The Dentist’s supply company to produce his systematized

molds of teeth. Thus the typal form method or geometric method of anterior

tooth selection gained universal acceptance. However further investigation by

Wright in 1936, Bell in 1978 and Mavroskufis et al in 1980 invalidate this

method of selection. But this method is probably still the way in which most

dentists select anterior artificial teeth.

Technique 10

Young proposed the selection of tooth form by “Mold guide sample” as

the 10th technique (in approximate chronological order).

Technique 11

“Wavrin Instrumental Guide Technique” presented in 1920 was based

on Berry’s Biometric ratio method and William’s Typal form teeth but its use

was limited to a single manufacturer’s product.

Technique 12

“Maxillary Arch outline form” projected by Nelson in 1920. This

technique assumed that the arch outline form was a valid method since it was

related to an individuals anatomy. This was invalidated by changes in arch

form due to resorption.

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Technique 13

“Wright’s Photometric method” proposed in 1936 was based on using a

photograph of the patient with natural teeth and establishing a ratio by

comparative computation of measurements of like areas of the face and

photograph. The simple unknown mathematical fomula could be used to select

teeth or to create correct vertical dimension. Minute inaccuracies in

measurements tended to diminish greatly the reliability of the technique so it

has enjoyed little usage.

Technique 14

“The multiple choice method” introduced by Myerson in 1937 was

based on a need for a selective range in labial surface characteristic of

transparent labial and mesial surfaces, varying surface colour tone, and

chracterization of teeth by time and wear. Harmony of tooth size and shape

with face size and shape was associated with this technique.

Technique 15

“Stein’s coordinated size technique” presented in 1940 was based on the

coronal index of 70 to 100 commonly used in prosthetic on 4 model teeth

representing the range of maximum frequency of use and on the common

variability in size of individual natural teeth. The index is the width percent of

the length. The variability is 0.5mm ; model size varied from 7.2 to 8.7 mm.

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Technique 16

“Anthropometric – Cephalic index method” projected by Sears in 1941

was based on the fact that the width of the upper central incisor could be

determined by dividing either the transverse circumference of the head by 13 or

the bizygomatic width by 3.3. Tooth length was in proportion to face length.

Technique 17

“Frame Harmony method” by the Justi company in 1949, is based on the

fact that the size and proportions of the teeth are in harmony with the general

bony proportions of the skeleton. The overall tooth size is selected by a

mathematical formula, 1/7th the total dimension of the upper and lower

edentulous ridges, with the dimensions of the individual anterior teeth

correlated with a developed table of tooth dimensions to give the indicated

over-all dimension. Other characteristic of tooth form are based on genetics,

and the comparison of such dental qualities of a near relative.

Technique 18

“Bioform technique” proposed by the Dentist’s Supply company in

1950 is based on the geometric outline forms of face and teeth – the “House”

classification for 4 basic and 3 combination typal forms, and 3-dimensional

harmony of tooth form and face form. It is associated with the tabular and mold

guide systems. This is currently in use.

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Technique 19

The “Trubyte tooth indicator” or “Selection Indicator Instrument”

method advocated by the Dentist’s supply company which is correlated with

William’s and House’s Typal form theory and the Tabular technique.

Technique 20

“House instrumental method” of projecting typal outline and profile

silhouettes onto the face by means of a telescopic projector instrument and

silhouette form plates. This was correlated with designated mold numbers and

size variation. This was proposed by House in 1939 and by the Dentist’s

Supply company in 1950.

Technique 21

“Automatic instant selector guide” of the Austenal company in 1951

correlated form, size and appearance in such a manner that only a single

reading was required to select the appropriate tooth mold based on dimensions

of denture space and harmony of face and tooth form.

These were the twenty one techniques detailing the evolution of the

selection of anterior teeth as described by Young in 1954.

Then in September 1955 Frush and Fisher created a revolution in the

field of dental esthetics by the introduction of Dentogenics. In a series of six

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articles published between 1955 and 1959 they described various means to

more natural dentures and many tips on how to avoid the ‘denture look’.

Krajicek in 1956 proposed methods involving the duplication of the

patient’s natural teeth either before or after extraction. Klein (1960), Hayward

(1968), Kafandaris and Theodoros (1974) suggested incorporating the patient’s

natural teeth in the denture. Van Victor in 1963 proposed the mold guide cast

technique.

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DENTOGENICS

Frush and Fisher in the first, of a series of six articles, published in 1955

introduced the dental community to “Dentogenic restorations”. According to

them, there was nothing in the field of esthetics that had not been considered

before. Yet a vacuum existed and the ‘Denture look’ prevailed.

Dentogenics describes a denture that is eminently suitable to the wearer

in that it adds to the person’s charm, character, dignity or beauty in a fully

expressive smile. Dentogenics then means the art, practice and techniques used

to achieve that esthetic goal in dentistry.

The authors describe the origin of the concept – Frush in 1952 met in

Zurich, Switzerland, a master sculptor by the name of Wilhelm Zech – who

ground and formed teeth for his dentist father. Zech experimented with the

molding, spacing and arrangement of teeth in artificial dentures with an artist’s

concept of what belonged in the mouth of a living human. His work inspired

Frush to take a new look at denture prosthetics and the Swissedent foundation

was established in Los Angeles, California in 1952, from where through

seminars and workshops, the concepts of dentogenics have disseminated.

Frush and Fisher in 1956 advocated sex identity in dentures by the

application of “Dentogenics”. According to them, the feminine form is

characteristically spherical with a roundness, smoothness and softness that is

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typical of women. Whereas the masculine form is cuboidal, with the hard,

muscular, vigorous appearance which is typical of men.

The procedure therefore is to select a basically ‘Feminine’ or

‘Masculine’ mold and then harmonize it to the individual patient depending

upon the personality and age factors by modifying individual teeth.

The authors describe a procedure they call depth grinding which

involves the accentuation of the third dimensional depth to eliminate the first

appearance of the artificial upper anterior teeth. With a soft stone, the mesio-

labial line angle of the central incisor is ground in a definite and flat cut,

following the same curve as the mesial contour of the tooth in order to move

the deepest visible point of the tooth further lingually. After this cut has been

made, a careful rounding and smoothing of the sharp angle made by the stone

must be accomplished and a perfect polish must be given to the ground surface.

It is necessary to develop the desired effect in depth grinding by a

consideration of these main factors – A flat thin, narrow tooth is delicate

looking and fits delicate women and involves little depth grinding. Whereas a

thick, “Bony”, big sized tooth, heavily carved on its labial face is vigorous and

is to be used exclusively for men. This involves rather severe depth grinding.

For the average patient, a healthy women or a less vigorous man, the

depth grinding will be an average between delicate and vigorous, the feminine

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or masculine characteristics being given by other tooth shaping, incisal

grinding and the positioning of the teeth.

Depth grinding reduces the width of the central incisors according to the

severity of grinding to be accomplished. Therefore, to maintain the normal

harmony of contrast in size between the six anterior teeth, a larger sized central

incisor of the same mold should be selected.

Again in 1956, Frush and Fisher discussed another aspect of

Dentogenics – the personality of a patient. They stated that the foundation for

dentogenic restorations is the personality of the patient – simply because the

basic ‘male’ or ‘female’ tooth form is a refinement of that tooth form which has

its inception in the personality factor. Likewise age is a refinement of the

personality factor. They devised the personality spectrum and explained the

precise prosthodontic application of the otherwise abstract word personality –

by the 3 divisions of the personality spectrum.

1. Delicate – meaning fragile, frail, the opposite of robust.

2. Medium pleasing – meaning normal, moderately robust, healthy and of

intelligent appearance.

3. Vigorous – meaning the opposite of delicate, hard and aggressive in

appearance, the extreme male animal, muscular type almost primitive,

ugly.

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The personality spectrum can be used in our artistic endeavour to inject

a variety of tooth form and tooth position, at the comprehensive level of

individual patient personality analysis. A small percentage of patients are

delicate, and a slightly larger percentage are vigorous. The remaining majority

of patients fall into the medium section of the personality spectrum, but all of

these have either vigorous or delicate tendencies.

The use of the dentogenic concept is made easier by considering the

smile as the primary objective personality trait of the patient. This primary

objective personality trait and the personality spectrum is used for the selection

of the mold category. These fundamental shapes must then be subjected to the

refining procedure of sex and age modifications.

The age factor in dentogenics, considered by Frush and Fisher in 1957,

determines the selection of the shade of the mold to be used in the denture.

Light shades are considered appropriate for young people and darker shades are

considered esthetic for older people. Also bluish incisal tinges are preferred for

the young and grayish shades for the older. Mold refinement is done by

producing worn incisal edges and cuspid tips, attritional and abrasional facets,

development of diastemata to indicate tooth loss and subsequent drifting.

Thus the dignity of advancing age may be portrayed in the denture.

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In 1958, Frush and Fisher propounded the Dynesthetic interpretation of

the dentogenic concept. Dynesthetics is a compounded word. The prefix ‘dyn’

is from the Greek word ‘dynamis’ meaning power. It implies movement,

action, change and progression in the esthetic phase of prosthodontics. This

dynamic value has been described as making the difference between an artifact,

any object without “life-like effect” such as a spoon, and a work of art or visual

objects that are alive in meaning such as a statue.

Therefore the application of dynesthetics allows a denture to be a work

of art and have a life-like effect against a denture lacking artistic treatment and

thus remain an artifact.

The dynesthetic techniques are rules which concern the 3 important

divisions of denture fabrication.

1. The tooth.

2. Its position.

3. Its matrix (visible denture base).

The selection and modification of the tooth according to dentogenics has

already been described. The positioning and denture base considerations are

beyond the scope of this seminar.

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THE GOLDEN PROPORTION

Of particular interest is the so called Golden proportion that exists

between the perceived widths of the upper anterior teeth.

Lombardi in 1973 and Levin in 1978 demonstrated that the width of the

central incisor is in golden proportion to the width of the lateral incisor. The

width of the lateral incisor to the width of the canine is also in golden

proportion as is the width of the canine to the first premolar. The golden

proportion exists when the ratio between a larger part ‘B’ (for example) to a

smaller part ‘A’ (for example) is 1.618.

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DISCUSSION

A practical approach to the selection of the anterior teeth is to consider

the size, form and color.

SIZE:

May be determined from:

- Pre extraction records.

- Marking the corners of the mouth on the occlusal rim gives the width of

the 6 anterior teeth.

- Marking the inter alar width on the occlusal rim gives the width of the 6

anterior teeth from cuspid tip to cuspid tip.

- Length may be determined by noticing visibility of the incisal edges and

relating this to lip length and dentogenics.

FORM:

Inspite of the body of research that invalidates William’s Typal theory,

clinically, it is observed to provide esthetic results and as stated by William

“Observance of this rule will always give you perfect harmony – the harmony

of opposition of line”.

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The form may also be selected considering first the personality of the

patient and then modified according to the sex and age of the patient to

individualize the mold.

Pre extraction records may also be of value in the selection of the form

of the anterior teeth.

COLOR:

Color of the teeth is to be determined by the skin coloring of the

individual. The color selected should be so inconspicuous so as not to attract

attention to the teeth. The squint test may be helpful in evaluating colors of the

teeth with the complexion of the face. With the eyelids partially closed to

reduce light, the dentist compares prospective colors of artificial teeth held

along the face of the patient. The color that fades from view first is the one that

is least conspicuous in comparison with the color of the face.

The age of the patient will also effect the color of the teeth. The general

rule is that darker teeth are more appropriate in older patients and lighter teeth

are more harmonious in young patients.

This rule however must be overruled for the patient who does not smoke

and takes food of slight pigmentation and may continue to have a relatively

light tooth body together with the normal color texture. This is an application

of dentogenics to the color selection.

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CONCLUSION

The selection of anterior teeth is an important part of the esthetic phase

of denture fabrication. It is essential not to be embroiled by the various

techniques aimed at making the task easier. What is necessary is the

development of an esthetic sense by the observation of natural dentitions in

response as well as in function so as to be able to create dentures that are living

things – belonging to a human being and not just mere artifacts that are poor

replicas of what has been lost.

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BIBLIOGRAPHY

1. BELL R.A. : The geometric theory of selection of artificial teeth : Is it

valid ?. JADA 97 : 637, 1978.

2. CLAPP G.W. : How the science of esthetic tooth form selection was

made easy. J. Prosthet. Dent. 5 : 596, 1955.

3. Dorland’s Illustrated Medical Dictionary. W.B. Saunders, 28th Ed. Pg

1666.

4. FENN, LIDELOW, GIMSON (1989) : Clinical Dental Prosthetics, 3rd

Ed., Wright.

5. FRUSH J.P. and FISHER R.D. : Introduction to dentogenic restorations.

J. Prosthet. Dent. 5 : 586, 1955.

6. FRUSH J.P. and FISHER R.D. : How dentogenic restorations interpret

the sex factor. J. Prosthet. Dent. 6 : 160, 1956.

7. FRUSH J.P. and FISHER R.D. : How dentogenics interpret the

personality factor. J. Prosthet. Dent. 6 : 441, 1956.

8. FRUSH J.P. and FISHER R.D. : The age factor in dentogenics. J.

Prosthet. Dent. 7 : 5, 1957.

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9. FRUSH J.P. and FISHER R.D. : The dynesthetic interpretation of the

dentogenic concept. J. Prosthet. Dent. 8 : 558, 1958.

10. HAYWARD D.E. : Use of natural upper teeth in complete dentures. J.

Prosthet. Dent. 19 : 359, 1968.

11. HICKEY J.C., ZARB G.A., BOLENDER C.L., (1985) : Boucher’s

prosthodontic treatment for edentulous patients, 9th Ed., Mosby, S.

Louis.

12. HEARTWELL C.M. and RAHN A.O. (1986) : Syllabus of complete

dentures, 4th Ed., Lea and Febiger, Philadelphia.

13. KERN B.E. : Anthropometric parameters of tooth selection. J. Prosthet.

Dent. 17 : 431, 1967.

14. KAFANDARIS N.M. and THEODOROU T.P. : Complete denture

technique using natural teeth. J. Prosthet. Dent. 33 : 571, 1974.

15. KLEIN I.E. : Immediate denture prosthesis. J. Prosthet. Dent. 10 : 14,

1960.

16. KRAJICEK D.D. : Personalized acrylic resin anterior teeth. J. Prosthet.

Dent. 6 : 29, 1956.

17. LEVIN E.I. : Dental esthetics and the Golden proportions. J. Prosthet.

Dent 40 : 244, 1978.

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18. MAVROSKOUFIS F. et. al : The face form as a guide for the selection

of maxillary central incisors. J. Prosthet. Dent. 43 : 501, 1980.

19. MAVROSKOUFIS F. et. al : Nasal width and incisive papilla as guides

for the selection and arrangement of maxillary anterior teeth. J. Prosthet.

Dent. 45 : 592, 1981.

20. PICARD C.F. : Complete denture esthetics. J. Prosthet. Dent. 8 : 252,

1958.

21. SEARS V.H. : Selection of anterior teeth for artificial dentures. JADA

23 : 1512, 1936.

22. VAN VICTOR A. : The mold guide cast – It’s significance in denture

esthetics. J. Prosthet. Dent. 13 : 406, 1963.

23. WRIGHT W.H. : Selection and arrangement of artificial teeth for

complete dentures. JADA 23 : 2291, 1936.

24. YOUNG H.A. : Selecting the anterior tooth mold. J. Prosthet. Dent. 4 :

748, 1954.

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CONTENTS

Introduction

Review of Literature

Dentogenics

Discussion

Conclusion

Bibliography

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