Transcript SELECTION AND ARRANGEMENT OF ARTIFICIAL TEETH

SELECTION AND ARRANGEMENT OF
ARTIFICIAL TEETH IN COMPLETELY
EDENTULOUS PATIENTS
Short Learning Objectives
• Anterior teeth selection
• Posterior teeth selection
• Arrangement of Teeth
INTRODUCTION
• The selection of artificial teeth for edentulous
patients requires a knowledge and
understanding of a number of physical and
biologic factors that are directly related to
each patient.
• Careful examination of the faces and teeth of
people with natural teeth will develop a sense
of dentofacial harmony that is the objective of
tooth selection and esthetics.
• There must be harmony of color, form, size,
and arrangement of teeth
Anterior tooth selection
• The factors of shade selection are:1. Age.
2. Sex.
3. Complexion.
4. Patient -preference
METHODS USING PRE-EXTRACTION GUIDES
It includes• Diagnostic casts,
• Photographs,
• Radiographs,
• Extracted teeth
Anterior tooth selection
• Factors to be considered for selection of
anterior teeth:
A. Shade (color)
B. Size
C. Form
METHODS USING ANTHROPOLOGICAL
MEASUREMENTSThese methods measures certain anatomical
dimensions and derive the size of teeth using certain
formula-
Circumference of the head
Width of the upper CI=------------------------------------------13
bi-zygomatic width
Total Width of the upper anterior =--------------------------------3.36
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Total Width of the lower anterior =---- Width of the upper
anteriors
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METHODS USING ANATOMIC LANDMARKS
Seven anatomic entities are used as guides to selection of
anterior teeth for size:
1. Size of the face
2. Size of the maxillary arch
3. Incisal papilla and the cuspid eminence or the Buccal
Frenum
4. Maxillomandibular relations
5. The contour of the residual ridges
6. The vertical distance between the ridges
7. The lips
Resorption Pattern in maxilla and
Mandible
• THE VERTICAL DISTANCE BETWEEN THE RIDGES:
– The length of the teeth is determined by the available
space between the existing ridges.
• THE LIPS
– When the teeth are in occlusion and the 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.
– It is best demonstrated when the letter F, as in fifty five is
pronounced
FORM OF ANTERIOR TEETH:• The form and outline of the anterior teeth can be
determined using the following factors:
1. Shape of the patient’s face or facial form
2. Patient’s profile
3. Dentogenic concept
Typal form theory: Leon Williams (1917)
According to this, the shape of the teeth should
be inverse of the shape of the face. Teeth
form can be• square,
• ovoid and
• tapering
Dentogenic concept
Dentogenics is the art, practice and technique of creating
the illusion of natural teeth in artificial dentures and is based
on the elementary factor influenced by sex, personality and
age of the patient.
It was first described by Frush and Fisher.
Dentogenic concept:
Sex:
– In female, the incisal angles are more rounded and
the teeth have lesser angulation while in males, the
incisal angles are rounded to a lesser degree.
– The incisal edge of the CI is parallel to the lips and
the laterals are above the occlusal plane in males
But in females it follows curve of the lower lip (CI &
LI)
– The distal surface of CI are rotated posteriorly for
females, LI overlapping CI.
– Reverse in males, providing masculine features.
Dentogenic concept:
Age:
– separated into young, middle or elderly.
– Due to decrese in muscle tone, sagging
of the cheeks and the lower lips occur.
To prevent cheek biting, horizontal
overlap of the posterior teeth can be
increase.
– Inter occlusal distance reduces with age.
Hence, mandibular teeth are more
visible than the maxillary teeth.
– In old patients the teeth tend to have
square form due to attrition, round
features disappears and line angle quite
prominent in those patients.
Dentogenic concept:
Age:
– Old patient have gingival recession, & can be reproduced
in the dentures
– The color of the teeth also changes with age.
Personality:
– It seems reasonable that a large vigorous type of persons
have teeth of a size and form with prominent markings,
different from those of a delicate appearing patient.
Arrange teeth according to personality
Dentogenic concept
MATERIALS OF TEETH:There are two main types:
1. Porcelain,
2. Acrylic
Porcelain teeth:
- vacuum fired and air fired. The vacuum is better because
they are harder and have luster. Generally porcelain teeth
are preferred particularly for young person because they look
more vital, very smooth and difficult to abrade.
MATERIALS OF ANTERIOR TEETH:Acrylic teeth:
They are made from acrylic resin, indicated when there is
insufficient inter-occlusal distance, and grinding becomes
necessary, also in situation where there are opposing natural
teeth, partial denture and gold bridge. They are inferior
when they are compared with porcelain because they can
not maintain luster for long time and abraded easily.
MATERIALS OF ANTERIOR TEETH
ACRYLIC TEETH :
PORCELAIN TEETH :
1- Not brittle, but poor abrasion 1- Brittle, more resistance to
resistance.
abrasion
2- Esthetic very good.
2- Excellent (does not stain).
3- Chemical bonding with
3- Mechanical bonding by pins
denture base.
or undercuts holes.
4- Easily ground and polish.
4- Difficult to grind and polish.
5- Transmit fewer forces to the 5- More forces to the mucosa.
mucosa.
6- Clicking on contact.
6- No clicking on contact.
7- Much lower than acrylic
7- Thermal expansion same as causes stresses in acrylic
acrylic denture base.
denture base.
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Posterior tooth selection
Posterior teeth are selected for color, buccolingual width,
mesiodistal length, vertical height (occluso-gingival length)
and occlusal form.
1- Shade (color):
- should be harmonized to the shade of anterior teeth,
maxillary first premolars are sometimes used for esthetic
more than function, so it's advisable to select premolar
teeth with lighter color than the other posterior teeth,
but not lighter than anterior teeth. Generally the shades
of posterior teeth are slightly darker than anterior teeth.
2-Bucco-lingual width:- should be slightly narrower than natural teeth to decrease
occlusal surfaces which direct less stress during function to
supporting tissue, and also enhance the development of the
correct form of polished surfaces of the denture.
3- Mesio-distal width:
-Narrower than natural ones.
-should be equal to the distance between canine line and
anterior border of maxillary tuberosity for upper teeth. For
lower teeth should be equal to distance between canine line
and anterior border of retro molar pad area.
4- The occluso-gingival height
- Controlled by the available inter-arch distance. The length
of the maxillary first premolar should be comparable to that
of maxillary canine to have the proper esthetic effect. The
height of posterior teeth usually divided into long, short,
medium. Long posterior teeth are generally more esthetic in
appearance than are shorter teeth.
5- Occlusal form:
Selecting the tooth to be used is based on the concept of
occlusion to be developed, the philosophy of occlusion to be
fulfilled, and the accomplishment approached. It is given in
the table below.
COMPARISION OF DENTURE TOOTH MOLDS AND OCCLUSAL CONCEPTS
TOOTH MOLD OCCLUSAL CONCEPT
20 or 30degree cusp
teeth
•
•
Monoplane 0- •
degree
•
•
•
•
ADVANTAGE
Centric jaw record, face bow,
protrusive records to semiadjustable.
Set upper anterior and
posterior teeth, then lowers
to cross-arch contact or
“balanced-occlusion”
•
Centric jaw record only
Simple articulator
Set 12 anterior teeth with
Overjet but no overbite
Set lower teeth in flat plane to
middle of retromolar pad
Set upper to match; no
attempt on contact on
excursions
•
•
•
•
DISADVANTAGE
SELECTION
Reported slightly more •
efficient in chewing tests
Posteriors appears more •
natural
•
•
•
•
Simplest of all recordings •
Simplest articulators
Quick arrangement of
•
teeth
Wide range of posterior •
tooth positions possible
No lateral stresses on
mucosa with parafunction
Easier for patients with
uncoordinated closures
Most time and
complexity of records
Limitations of
anterior tooth
positions
Restriction of
posterior tooth
positions to that
allowed by Cuspal
anatomy
Flat premolars may
appears less esthetic
Reported as less
aesthetics
Anterior esthetics
need more Overjet
and no overbite
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COMPARISION OF DENTURE TOOTH MOLDS AND OCCLUSAL CONCEPTS
TOOTH MOLD OCCLUSAL CONCEPT
Flat teeth
with
compensating
curve or
second molar
ramp




Combination 
or

“lingualized”
occlusion

Centric jaw record
Semi-adjustable articulator
Anterior teeth with Overjet
and slight overbite
Posterior set to contact on at
least 1 point on non-working
or balancing side
ADVANTAGE


Centric jaw record

Monoplane lower posterior
teeth set to retromolar pad

Anatomic upper posterior
teeth set with only lingual, not 
buccal cusp touching
SELECTION
DISADVANTAGE
Simple to set up; allows for 
more esthetic overlap of
anterior teeth

The posterior point contact
maintain denture base
stability on excursion or
parafunction
Upper premolars appear
natural
Some range of posterior
tooth position allowed
Reported slightly better
chewing than monoplane

Slightly more
laboratory set up
Premolars appear
flat if visible
Some grinding
needed to create
upper cusp
tip/lower fossa
contacts
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Posterior tooth selection
10°
SELECTION
20°
33°
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ARRANGEMENT OF THE TEETH
Arrangement Of Anterior Teeth
It is important that the artificial anterior teeth
are placed in the same antero-posterior position
and at the same length as natural teeth to
provide adequate esthetics and phonetics.
RESIDUAL ALVEOLAR RIDGE
• In patient with long edentulous period, much
bone could have been lost from the residual
alveolar ridge. In this situation, artificial teeth
should not be placed against the ridge
• As a general rule: the longer the natural teeth
have been out the farther the artificial teeth
should be from the ridge
• The teeth should be placed closer to the residual
ridge when there is less shrinkage and farther
from ridge when there has been more resorption
Arch Form And Shape
RELATIONSHIP TO INCISIVE PAPILLA
• Incisive papilla is a guide to anterior tooth position
because it has a constant relationship to the natural
CI.
• A line marking the centre of the incisive papilla on the
cast is extended forward onto the labial surface of the
cast and CI are set on either side of this line. However
in few cases, where facial mid line doesn’t coincide
with papilla, better to take facial midline as guide.
• Incisive papilla is also a guide to the antero-posterior
position of the teeth. Labial surfaces of the CI are
usually 8-10 mm in front of the papilla
 Incisive papillae
Midline of upper denture
Dr Abhilash
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Role of Incisive papillae
Maxillary anterior teeth arrangement
Arrangement of the mandibular
anterior teeth:
Horizontal overlap (over jet) and
Vertical overlap (over bite):
Arrangement Of The posterior Teeth
Standardized parameters
1. Curve of Wilson' as transversal compensating
curve.
2. Curve of Spee' as sagittal compensating curve.
3.Optimum intercuspation of the antagonists.
Curve of Wilson
Curve of Spee
Common errors in arrangement of
teeth.
1. Lack of rotation of anterior teeth to give a narrower effect.
2. Setting mandibular anterior teeth too forward in order to
meet maxillary teeth.
3. Failure to make the canine the turning point of the arch.
4. Setting mandibular 1st premolar to the buccal side of the
canines.
5. Setting the mandibular posterior teeth too far to the
lingual side in the 2nd molar region which cause tongue
interference and mandibular denture displacement
6. Failure to establish the occlusal plane at the proper level
and inclination.
7. Establishing the occlusal plane by an arbitrary line on the
face.
Take Home Message…..
• Teeth selection should be in harmony in color, shape
and size with the patient’s face, sex and age for a
successful fabrication of complete denture prosthesis.
• Teeth should be positioned in harmony with intraoral
and circumoral muscle activity and adjusted so that
they occlude and articulate evenly.
• Several different prosthetic tooth molds have been
produced, and each has some purported advantages.
In the absence of a clear advantage, tooth molds,
selected should be esthetically pleasing and have a
simple procedure to set up.
MCQs
1.
a.
b.
c.
d.
Dentogenic concept was given byBoucher
Frush and fisher
Rudd
Winkler
2. Distance of labial surfaces of the central
incisors from incisive papilla isa. 5-7mm
b. 6-8mm
c. 8-10mm
d. 10-12mm
3. Total width of upper anterior as compared to
bizygomatic width isa. ½
b. 1/3
c. ¼
d. 1/5
4. Antero-posterior compensating curve is
provided bya. Curve of Wilson
b. Curve of Monson
c. Curve of spee
d. Curve of Berry
5. Total Width of lower anterior as compared to
upper anterior is
a. 2/3
b. ¾
c. 4/5
d. 5/6