ESTHETICS IN COMPLETE DENTURE
CONTENTS
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Introduction
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Review of Literature
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Dentogenics
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Discussion
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Conclusion
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Bibliography
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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.
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
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.
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.
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 ovoid, 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.
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.
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 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.
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 1/4th 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 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.
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.
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.
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 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.
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 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 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.
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.
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.
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.
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”.
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.
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.
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.
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.
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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