SELECTION OF ARTIFICIAL
TEETH FOR COMPLETE
DENTURE
.
.
Introduction
A knowledge and understanding of a number of physical and
biological factors directly related to the patient are required to
appropriately select artificial teeth to rehabilitate the occlusion.
The goals for this phase of therapy are to construct complete
dentures that (1) function well, (2) allow the patient to speak
normally, (3) are esthetically pleasing, and (4) will not abuse
the tissues over residual ridges. The prosthodontist is the best
person to accumulate, correlate, and evaluate the
biomechanical information so that the artificial teeth selected
will meet the individual needs of the patient. The selection and
arrangement of artificial teeth is a relatively simple non-time
consuming procedure, but it requires the development of
experience and confidence.
ANTERIOR TOOTH SELECTION
•
•
•
•
•
Pre extraction guide
Post-extraction record
Size of anterior teeth
Form of anterior teeth
Color of teeth
ANTERIOR TEETH SELECTION
Clinical judgment and experience still remain the final
criteria in selection of the proper width and mold, The following are
among the most widely used and suggested methods for anterior tooth
selection.
A. Patient pre extraction records:
1. Diagnostic casts of the patient's natural or restored teeth prior to
extraction of the remaining teeth.
2. Request the most recent photographs of the patient before loss of his
teeth.
3. Measurements may also be made from radiographs of the teeth,
making allowances for lengthening or foreshortening .
4. The use of facial photographs is usually of far more help to the
dentist in determining the placement of anterior teeth, arch form, and
lip support than for the actual size of the mold of an artificial tooth.
5Teeth of close relative – This method is usually followed only if other
records are not available.
B. Postextraction examination— if the patient is edentulous and
wearing complete dentures, examine the patient with the dentures he
presently wears, paying attention to the following:
1. Do the teeth appear lost in the face (too small or set too far
in)? .
2. Do the teeth appear too small, regular, and set like a picket
fence?
3. Are the teeth set too high, and are they almost lost from view
during speaking and smiling?
4. Are the teeth overbearing, too large, but of proportion in their
length and breadth to the size and dimensions of the face and head?
5. Do the maxillary teeth show in smiling, and the mandibular
teeth during speech?
All of these observations should be used in arriving at a
determination of which teeth should be selected for the trial denture. On
the basis of the teeth the patient is wearing, determine whether to
choose teeth that are larger or smaller, longer or shorter, wider or
narrower, flatter or having a more curved labial surface.
SIZE OF THE ANTERIOR TEETH
• Size of the face
• Size Of Maxillary Arch
• Incisive papilla and the canine eminence
• Maxillo-Mandibular Relation
• Contour of the residual ridge
• Vertical distance between the ridges
• Lips
SIZE OF THE ANTERIOR TEETH
Anatomic entities used as a guide for anterior teeth
size:
Size of the face:
Width of the central incisor = one sixteenth of the bizygomatic width of the face.
Combined width of the six anterior teeth = slightly less
than one third of the bizygomatic breadth of the face.
Size Of Maxillary Arch
The mold be used to make measurements of the maxillary cast.
Accurately contoured occlusal rims are required. Make the
measurements from the crest of incisal papilla to the hamular
notches and from one hamular notch to the opposite notch. The
combined length of the triangle in millimeters is used on the
selector. The circular slide rule indicates the tooth sizes, anterior
and posterior, for both arches.
LIMITATION
These criteria’s will not be usable in situations like spacing, rotating
and overlapping. The excessive or unusual loss of bone may also
influence the size of anterior teeth (length)
When the discrepancy between the size and related arch exist the
selection of anterior teeth is more governed by face size than the
arch size
• Incisive papilla and the canine eminence – the
combined width of the six anterior teeth is equal
to the length of a line drawn on the cast at the
distal termination of one canine eminence to the
other.
•
Intra-orally, the patient is requested to relax
with the lips touching. A mark is made at the
corners of the lips. The distance between the two
marks on either side is equal to the combined
width of all the anterior teeth.
• . Maxillo-Mandibular Relation – Any
disproportion in the size between the maxillary
and mandibular arches influences the length,
width and position of the teeth. If mandible is
protruded; anterior teeth are larger, if mandible is
retruded; anterior teeth are smaller.
• . Contour of the residual ridge – teeth should be
placed in relation to follow the contour of the
residual ridges that existed when natual teeth
were present.
• Vertical distance between the ridges – according
to the available inter-arch space length of the
teeth can be selected. Minimal of the denture
base should be visible in the final prosthesis.
• . Lips – During relaxed state the labial surface of
the maxillary anterior teeth support the upper lip.
When the teeth are together the incisal edge of
the maxillary incisors supports the superior
border of the lower lip
• FORM OF THE ANTERIOR TEETH
•
•
Factors governing the form of the anterior
teeth:
Form and contour of the face: from the frontal
aspect the shape of the face can be classified as
–
–
–
–
–
Square
Square tapering
Tapering
Ovoid
Shapes of the artificial teeth chosen to be in harmony with
the size of the patient’s face
• From the lateral aspect the facial profile can be
classified as:
–
–
–
–
Straight
Concave
Convex
Form of the artificial anterior teeth should conform to
the form of the face.
• The labioincisal contour of the teeth usually
conforms to the profile of the individual
The geometric figures-square, tapering, ovoid,
and combinations there of serve as a starting
point in selecting the tooth form as it is
viewed from the frontal aspect .
• To determine the facial profile, observe the relative
straightness or curvature of the profile. 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. If the points of the forehead and of
the chin are recessive, the profile is curved
• Sex: Curved features are associated with feminity
and square features are associated with
masculinity. Teeth selected for females are more
ovoid or tapering; whereas for males are more
squarish, and sharp edged.
• Age: Aging process affects the entire masticatory
apparatus in general including the teeth. Teeth
wear at the incisal edges, labial surface becomes
more flatter and outline appears more squarish.
Dentogenic concept
Dentogenics is the art , practice, and technique of creating
illusion of natural teeth in artificial dentures and is based on
the elementary factors suggested by the sex , personality and
age of the patient.
Frush and Fischer established the dentogenic concept of
denture construction.
These authors wrote that gender, personality, and age could be
used as guidelines for tooth selection, arrangement, and
characterization to ‘‘enhance the natural appearance of the
individual.’’
COLOR OR SHADE OF ANTERIOR TEETH
Color is the sensation resulting from stimulation of the
retina of the eye by light waves of certain lengths. Shade is the
degree of darkness of a color with reference to its mixture with
black. When a tooth is viewed for the purpose of determining its
color, two principal colors yellow and gray are evident. The yellow
is more prominent in the gingival third, and the gray is more
prominent in the incisal third. The principal modifications are
termed hue. The degree of intensity of the hue, as measured by its
freedom from mixture with white, is saturation. Hue of the tooth is
actually the quality that the prosthodontist attempts to
duplicate. One other slight modification appears in teeth with thin
incisal edges. The yellow disappears, and the edge appears blue
gray. This is the only place that blue appears in a tooth.
The position of the patient and the source of light are very
important in color selection. The patient should be in an
upright position. The dentist should be in a position so that
the teeth are viewed in a plane perpendicular to the dentist's
plane of vision.
The teeth should be observed from different angles to
make certain that the shadows do not influence the color. The
patient's mouth should not be opened too wide but should
remain a dark cavity as in ordinary conditions.
White light is considered suitable. White light may be
secured from artificial sources if provided with the proper
filters. Eyes fatigue to color perception very rapidly and for
this reason they should not be focused on a tooth for more
than a few seconds
• If the proper shade is hard to establish the tooth and the
shade guide should be viewed from a distance of 6 or 8
feet.
• The color of the teeth, like the form, must be in harmony
with the surrounding environment if they are to appear
pleasing. Harmony should exist between the color of the
teeth and the color of the skin, hair, and eyes. The color
of the skin is a more reliable guide.
• A female patient’s cosmetics must be considered in
harmonizing with the complexion.
• Selecting The Color Of Artificial Teeth
• Observations of the shade guide teeth should be
made in three positions:
outside the mouth along the
side of the nose, will
establish the basic hue,
brilliance, and saturation
2) 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
3) under the lips with only the
cervical end covered and the
mouth open, will simulate
exposure of the teeth as in a smile.
Basic considerations are the harmony of tooth color with
the color of the patient's face and the inconspicuousness
of the teeth. The color selected should be so
inconspicuous that it will not attract attention to the
teeth.
The color of the teeth should be observed on a bright day
when possible, with the patient located close to natural
light. The teeth should also be observed in artificial light,
since denture patients are often seen in this environment.
The "squint test" may be 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 view first is the one
that is least conspicuous in comparison to the
color of the face.
• Although some person’s natural teeth become darker
with age, there are many exceptions to this; it is
therefore incorrect to establish a rule that prescribes
light teeth for young patients and darker teeth for older
ones.
• Tooth color must be in harmony with the facial coloring
at the time the dentures are made. Color of a tooth
changes immediately when it is removed from the
mouth and becomes non vital; it blanches further as the
tooth dries out.
• Thus, extracted teeth are valuable for size and form
selection but should not be used for color selection.
Posterior Teeth Selection
The selection of posterior teeth likewise involves
shade, size, number, and form
SHADE OF POSTERIOR TEETH
The shade of the posterior teeth should harmonize
with the shade of the anterior teeth. As noted
previously, the maxillary premolars are sometimes
used more for esthetic than for functional purposes.
Bulk influences the shade of teeth, and for this reason
it is advisable to select a slightly lighter shade for the
premolars if they are to be arranged for esthetics.
• Buccolingual Width of Posterior Teeth
The buccolingual widths of artificial teeth
should be less than the widths of the natural
teeth they replace. Artificial posterior teeth
that are narrow enhance the development of
the correct form of the polished surfaces of
the denture by allowing the buccal and lingual
denture flanges. to slope away from their
occlusal surfaces. These narrower forms,
especially in the lower denture, assist the
cheeks and tongue in maintaining the
dentures on the residual ridge.
Mesiodistal Length Of Posterior Teeth
The length of the mandibular residual ridge from the
distal of the canine to the beginning of the retromolar pad
is usually available for artificial posterior teeth. If the
residual ridge anterior to this point slopes upward, smaller
or fewer teeth must be used to avoid having a tooth over a
pronounced incline at the distal end of the ridge. This
shortened occlusal table will often prevent the lower
denture from sliding forward when pressure is applied on
the molars.
• The total mesiodistal width in millimeters of the four
posterior teeth is often used as a mold number. For
example, mold 32L signifies that the four posterior teeth
have a total mesiodistal dimension of 32 mm and a long
occluso-cervical length.
• The posterior teeth should not extend too close to the
posterior border of the maxillary denture because of the
danger of cheekbiting. However, if the posterior teeth
do not extend far enough posteriorly, the forces of
mastication will place a heavier load on the anterior part
of the residual ridges.
Posterior teeth are not arranged over the
retromolar pad, because:
• the pad is too soft and too easily displaced, has
glandular tissue which is hurt
• Putting teeth over it will allow the denture to tip
during mastication.
• Tendon of Tempolaris is inserted in the
retromolar region tends to displace the denture
Vertical Height of the Facial Surfaces of Posterior Teeth
It is best to select posterior teeth corresponding to the interarch
space and to the height of the anterior teeth. Artificial posterior
teeth are manufactured in varying occlusal cervical heights.
The height of the maxillary first premolar should be
comparable with that of the maxillary canines to have the proper
esthetic effect. Without this relationship, the denture base material
will appear unnatural distal to the canines. Ridge lapping the
posterior teeth can be done without sacrificing leverage or
esthetics.
The form of the dental arch should copy, as nearly as
possible, the arch form of the natural teeth they replace.
Types of Posterior Teeth According to Materials
For many years, porcelain was the favorite tooth material because of the
rapid wear of acrylic resin. However, with the tendency for porcelain to
chip and fracture, acrylic resin teeth have gained in popularity. Improved
acrylic resin teeth and newer composite resin teeth are more wear
resistant, and they have supplanted porcelain during the past two decades
Acrylic resin or composite resin posterior teeth are specifically called for
when they oppose natural teeth or teeth whose occlusal surfaces have
been restored with gold. These resin teeth reduce the possibility that the
artificial teeth will cause unnecessary abrasion and destruction of the
natural or metallic occlusal surfaces of the opposing teeth
SELECTION OF MATERIAL FOR ARTIFICIAL
TEETH
Porcelain Teeth
Advantages: Wear is clinically insignificant over
a long period of time.
No significant loss of vertical dimension.
Can be ground and polished and will hold shape
for years.
Allow for total rebasing procedures.
Maintain efficiency for years.
Disadvantages: Difficult to grind and fit into
close inter ridge space without fracturing or loss of
retention in the base.
Cause dangerous abrasion to opposing gold crowns and natural
teeth.
Have a sharp impact sound.
Ground surfaces must be highly polished to reduce friction and
prevent chipping.
Will not bond to the base material.
Potential for marginal staining due to capillary leakage .
Acrylic Resin Teeth
Disadvantages: Wear is clinically significant.
Loss of occlusal vertical dimension due to wear.
Occlusal surface altered by wear is such that in five to seven years they
are inefficient and usually worn to a reverse curve.
Advantages: Do not chip, and have softer impact sounds. Self adjusting
and self-polishing.
Easy to grind into close inter ridge space. Potential for bond to base
material.
Types of Posterior Teeth According to Cusp
Inclines
Posterior artificial teeth are manufactured with cusp inclines that
vary from steep to flat. 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 of both of
these goals with the least complicated approach .
A- teeth to be balanced in centric and eccentric positions – cusp
teeth (anatomic teeth)
B- posterior teeth to disocclude in eccentric jaw movement –
cusp or monoplane teeth (semi anatomic teeth)
C – posterior teeth to be arranged in flat plane and balanced in
centric occlusion position only- monoplane teeth (non anatomic
or zero degree teeth)