Guide to Selecting Anterior Tooth Size and Shape

Anterior Tooth Selection.
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


Introduction.


Anterior teeth selection and
arrangement is an area of
prosthodontics where art dominates
science,where esthetics is the major
concern,and where knowledge must
be applied to create a pleasing
appearance while simultaneously
maintaining oral function.

Introduction.
The anterior teeth are primarily
selected to satisfy esthetic
requirements.
 Posterior teeth's are selected to
satisfy masticatory functional
requirements.
Technically, the anterior teeth are
composed of 6 maxillary and 6
mandibular teeth's.



Introduction.
Exceptions:
o Sometimes maxillary first premolar is
considered more for esthetics than for
masticatory function.
o Sometimes in class 2 situations
maxillary cuspids assume a functional
role by addition of lingual centric stops.




Patients expect 3 basic things form
their complete dentures.
• Favorable appearance.
• Comfort.
• Chewing ability.


Studies conforming
importance of esthetics in
complete dentures
1. Brewer, Reibel and Nassif
1967:

JPD

• 12 patients received 7 sets of
dentures each made by 7 dentists.
• Each patient preferred the best
looking dentures.


2. Straus et al. JPD 1977
• 64 patients were asked how their new
complete dentures improved their self
image.
• Nearly all the patients responded that
the new dentures improved their
appearance,increased self
confidence,and provided an overall
sense of well being.



1.
2.
3.
4.

There are four main considerations
in selecting the anterior teeth.
Tooth size
Tooth mold
Color
Tooth material


Pre-Extraction Guides.


Photographs







More accurate than any other guide.
Shows the natural teeth or at least the
incisal edges.
Provides information about width and
outline form of the teeth.
Known factors:
• Width/length on photo.
• interpupillary distance on photo
• Interpupillary distance on patient





Unknown factor: length or width of
teeth to be selected.
Recent photographs are of much value.

•Natural teeth at 20 years

•65 years:
Poor
esthetics
with 15
year old
dentures.

New
denture
s made
with the
help of
phtogra
ph

Bindra et al JPD 2001




The technique described by wehner
et al is of proven value in calculating
the width of a central incisor when
the only available evidence is a preextraction photograph.
However, it is of value only when the
photograph is a full-face portrait of
sufficient size.

Diagnostic Casts.




Diagnostic casts of patients natural
or restored teeth.
Size and form of the anterior teeth
can be determined.


Radiographs.




Can help in knowing size and form of
the lost teeth.
Disadv
• Are always slightly enlarged.
• Distortion may be there.


Teeth of Relatives.


Sons or daughters tooth size , color,
and arrangement can be effectively
used in selecting and arranging
artificial teeth for their parents.


Extracted teeth.




Provides information as to the size
and form.
Not to be used for selecting color.


Selection of Size.


There are 2 dimensions to consider
• The
• The

mesiodistal width.
inciso-gingival length.


Measurement edentulous
casts.




Inaccurate due to resorption of
ridges.
Occlusal rims to be constructed for
accurate measurements.






Gives the estimation of placement
of apex of upper canines.
Extension of parallel lines from the
lateral surfaces of the alae of the
nose onto the labial surface of the
upper occlusion rim.


Relationship between
intercanine distance and nose
width



It falls in the
range 28-45mm
Since anterior
teeth are
arranged in an
arc. the divider
has to be opened
by 3-4mm more
than the value of
the nose width.




Distal surfaces of the natural canines
is usually located neat the corner of
the mouth.


Sketching on occlusion rims
By Kitzis.
occlusion rim
reduced till 1-2 mm
visible.
Proper contour is given
.
Some wax trimmed
from labial aspect
and replaced with
warmed aluwax.







Wax to be molded by patient with
functional movements of patients
and manual movement by dentist
The incisal portion of the rim is
adjusted to follow the contour of
the line of the lower lip.







Mark the midline of the
face.
Sketch in desirable
shape ,size ,and
contour of the teeth.
This gives more
accurate indication of
the actual
portion(incisal) of the
anterior teeth that will
show during speech
and smiling.


General guide .


Upper anterior teeth whose overall
width is less than 48mm are
relatively small teeth. Those listed as
over 52mm are relatively large teeth.


Anthropometric measurements.
Found from a study of 555 skulls.
 Greatest bi zygomatic width /
16
-gives
approximation of the width of
the upper central incisors.
- also known as house
and loop’s rule.
 Greatest bi zygomatic width /
3.3
-Overall width of the
upper six anterior teeth.





Lateral incisor are approximately 2
mm narrower and canine 1 mm
narrower than the central incisors.
A facebow maybe used utilized to
obtain these measurement.


The ratio of cranial circumference to
the width of the upper anterior teeth
10: 1
In 90% of 509 subjects in a study be
kern,1967



Length of central incisor


Facial measurement method
• Distance from the hair line to the
gnathion in millimeters with the face at
rest and divide this by 16.



Wax rim method.
• Instruct the patient to smile
• Place a line on the rim at that point to
which the lip elevates.
• General guideline: the maxillary lip
comes close to the gingival neck of the
tooth when a patient smiles broadly






Amount of central incisor visible in
young-3 mm.
In old – 11/2 mm.
The amount of tooth seen depends on
following factors.
•
•
•
•

Length of upper lip
Mobility of upper lip
Vertical height of occlusion.
Overbite.

Using trubute tooth indicator.


Size of the maxillary arch.


Mold selector method.
• Accurate contoured occlusal rims are
required.
• Make the measurements from the crest of the
incisal papilla to the hamular notches and
from one hamular notch to the opposite
hamular notch.
• the combined length of the 3 legs of the
triangle in millimeters is used on the selector.
• When discrepancies between face size and
related arch size exist,the selection of
anterior teeth should be governed more by
face size than by arch size.

Universal dental company mold
selector








Superimpose median
line
and move scanner to
touch the cuspid line
Mold width is
indicated in lower
scale.
Read the mold length
in the transparent
area.


Incisal papilla – cuspid
eminence/buccal frenum.






A line is placed on the cast at the
distal termination of the eminence.
When eminence are not discrenible a
line is placed slightly anterior to the
attachment of buccal frenum.
Ruler should follow contour of the
ridges and in midline should be
placed on the anterior border of the
incisive papilla.

Maxillo-mandibular relations.






In protruded mandible the anterior
teeth's are frequently larger than
normal.
If mandibles are retruded, the
mandibular anterior teeth are
frequently smaller.
In protrusion the face is usually
longer and longer faces usually
require longer teeth's.

Vertical distance between the
ridges.




The length of teeth is determined by
the space between the ridges.
When space is available it is
advisable to use long teeth.


Lips.







Help in determined the length of the teeth.
The maxillary incisal edge extends inferior to
or slightly below the lip margin.
When teeth are in occlusion and lips are
together,the labial incisal third of the
maxillary anterior teeth supports the superior
border of the lower lip.
In speech the incisal edges of the maxillary
anterior teeth contact the lower lip at the
junction of the moist and dry surfaces of the
vermilion border. As in pronouncing fifty five.

Inner canthal distance




Inner canthal distance
can be used to estimate
the mesiodistal width of a
maxillary central incisor
for an edentulous patient.
Aleem abdullah JPD 2002









Size of the teeth should be in
proportion to the size of the face
and head.
Larger persons have larger teeth
But a large person may have small
teeth with spaces between the
teeth.
Or a small person may have large
irregular aligned teeth.








Woman have smaller teeth than
men.
Lateral incisor should look more
delicate in woman.
Size difference between central and
lateral incisors should be more
distinct in woman.

Selection Of Form(shape or
mold).







Form of artificial anterior teeth should
harmonize with the shape of the
patients face.
Outline form is considered from a front
view of the patient.
The face from is identified by
connecting the following points on the
lateral aspect of the face;
•
•
•

the forehead,
the zygomatic arch
Angle of the mandible.

4 basic Outlines of faces


This was firs considered important by
williams and house and loop (Leon
williams classification)
• Square


Square tapering

• Tapering
• ovoid






The shape of
the maxillary
central incisor
should
resemble the
shape of the
face if it were
inverted.
This method
selection is
also called as
Geometric








Most dental manufacturers base
their entire systems of tooth
selection on these typal forms.
As ovoid teeth are not usually
seen in an ovoid shaped face
,Scientifically this method of
selecting teeth form is flawed.
Wright found that 60.7% of his
subjects had natural maxillary
central incisor that were not the
inverted facial forms.







Bell examined the maxillary central
incisors of 31 subjects whose natural teeth
were considered esthetically acceptable.
There was no correlation between the
form of face and the form of the maxillary
central incisors.
Conclusion: though flawed this approach
may be reasonable from an artistic point
of view.

Lee 1962








Compares the
width of face
and teeth at
At level of
foreheadgingival third
At level of
zygomata.maximum width
At level of lips.at incisal tip.


Relation between tooth shape
and arch shape


Tooth curvature


The form of the tooth should
conform to the contour of the face as
considered from the
labial,mesial,distal and incisal
aspects.

Tooth manufacturers labels its tooth
molds F(flat ) or C (curved)
according to the labial surface.







The shape of labial surface is more
important than outline form.
Labial surface when viewed from the
mesial should show a contour
similar to that when viewed in
profile.
“This approach to the
problem,although scientifically
unsound,was used by many tooth
manufacturers and is ,perhaps,the
basis of tooth selection most often
used today.”
-sharry








Check three points: the forehead,the
base of the nose,and the point of the
chin.if these three points are in
line ,the profile is straight.
3 types of profiles are
Convex
straight
concave



Labial surface of
the tooth when
viewed from the
incisal should show
a convexity or
flatness similar to
that seen when the
face is viewed
from under the
chin or from the
top of the head.

Selection of Shade.


Color has 4 qualities.


hue






Hue it is the specific color produced
by a specific wavelength of light
acting on the retina.
The hue of the teeth must be in
harmony with the color(Hue) of the
the patients face.
In teeth guides yellow is the
dominant hue.



Saturation (chroma)
• It is the amount of color per unit
area.
• Some teeth appear more yellow than
other .I.e hue is same but there is
more of it.



Brilliance (value) it is the lightness
or darkness of an object.
• The relative amount of white or black
in the teeth determines their
lightness or darkness.



People with fair complexions
generally have teeth with less color
and colors are less saturated.




Translucency








It is the property of the object that permits
the passage of light through it but does not
give any distinguishable image..
The apparent color of teeth is different
when the lightening of the interior oral
cavity is changed.
When the mouth is nearly closed,the teeth
will appear darker than when it is open
wide and the interior well lighted.
When light is reflected through the teeth
from the oral cavity,the teeth will appear
lighter and more pink than in other light
situations.






The basic caucasian color is yellow.
Complementary color of yellow is
blue.
Staring at blue card or cloth for 30
seconds make a more accurate
observation of the yellow color.


The color of hair




is unreliable and can be inaccurate
because hair color changes more
rapidly than tooth color.
People can change the color of hair
from week to week.


Color of eyes.




Color of eyes has been suggested as
guide to select the color of teeth.
Not a sound method since color of
Iris is so small compared to total
face and the eyes are not close to
the teeth.

Color of face.


It should be the basic guide to select
tooth color.


Age and color








Color of natural teeth progressively
darkens with age.
Pulp chamber becomes smaller with age
due to deposition of secondary dentin
This makes the tooth more opaque and
reduces the effect of pulp color.
As wear occurs due to abrasive forces the
tooth becomes smoother and more
reflective.






Wearing of incisal edges, losing of
enamel and translucency and dentin
picks up stain.
Teeth’s take a brownish tinge
particularly the incisal edges of lower
anterior.


Jaw relation and color.






Class 1 same selected for both the
arches.
Class 3 : prognathic patient slightly
darker teeth for the lower arch than
the upper as lighter teeth will stand
out.
Class 2 : lighter teeth than the
upper to give the illusion that the
teeth are more anterior than they
really are.

Selecting the color.





It should be done in 3 positions
Outside the mouth along the side of
the nose.
It will establish the basic
hue,brilliance,and saturation.










Under the lips with only
the incisal edge exposed.
Will reveal the effect of
the color of the teeth
when the patient’s mouth
is relaxed.
Under the lips with only
the cervical end covered
and the mouth open.
Will simulate the
exposure of the teeth as
in a smile.

Squint test






Helpful in evaluating colors of 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 the view first is
the one that is least conspicuous in
comparison to the color of the face.

Hallarman, 1971


There is no correlation between tooth
color and
• Natural hair color
• eye color.
• Skin color of forehead or cheek.






Canines are darker than central
incisors
Color darkens with age.
Females have lighter natural teeth.

Selection of tooth material.






Conventional acrylic resin
Interpenetrating polymner
network(IPN) acrylic resin
Composite resin teeth
Porcelain.


Indications for resin teeth.





Recent extractions
Immediate dentures
Limited interocclusal distance.
If current denture producing clicking
sound.


Interpenetrating polymner
network(IPN) acrylic resin





By dentsply international.
This tooth material is non filled
,highly cross linked copolymer with
an interpenetrating polymer network.
It is harder more abrasion
resistant,more stain resistant and
more heat resistant than
conventional resins.

Composite resin teeth






Vivosit (orthosit- posterior teeth) by
Ivoclar.
It consists of an organic filler and liquid
matrix based on a modified Bowen resin.
Liquid matrix and the organic filler
contain approximately 20% Pyrolytic
silicium dioxide,which is used as a
thickening and strengthening agent.








Pyrolytic silicium dioxide has particle
size of 10 to 400 A which is less than
wavelength of visible light- it makes
for a highly esthetic appearance.
It chemically bonds with the denture
base material.
It has better wear resistance than
the conventional acrylic resin.

Porcelain teeth.








Highest wear resistance.
Good stain resistance.
Disadv: clicking sound in
nervous patients and with
those having neuromuscular
coordination problems.
More prone for chipping and
fracture.
Cannot be given when
interarch space is less.

Resin anteriors and porcelain
posteriors.


Maxillary anterior
• Opposing mandibular natural teeth with distal
extension partial denture.
• It allows for wear of acrylic anterior if ridge
resorption and settling takes place over a
period of time and patients do not return for
proper denture Rebasing services.



Mandibular anteriors
• Accn to payne “ longer lingual slopes, are less
apt to chip and will wear as settling
occurs.they can be ground and reshaped to
look more natural and their incisal edges can
be easily stained with darker cold cured resin
where desirable.

Dentogenic concept




By frush and fisher on 1957
Also called SPA theory
Sex
• male
• Female



Personlity

• Vigrous delicate



Age
•
•
•

Young
Middle age
Old.

Thank you
For more details please visit


Guide to Selecting Anterior Tooth Size and Shape

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Andere mochten auch

Andere mochten auch (16)

Ähnlich wie Guide to Selecting Anterior Tooth Size and Shape

Ähnlich wie Guide to Selecting Anterior Tooth Size and Shape (20)

Mehr von Indian dental academy

Mehr von Indian dental academy (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Guide to Selecting Anterior Tooth Size and Shape