Al Azhar university Removable Prosthodontics Lama El Banna Dr. Waseem Moshtaha

1. Tooth selection
Dr. Waseem Bahjat Mushtaha
Specialized in prosthodontics

2. Tooth selection
The selection of teeth for complete dentures is
classified into:
I- anterior teeth selection.
II- posterior teeth selection.

3. The anterior teeth are primary selected to
satisfy esthetic requirements, whereas the
posterior teeth are primarily selected to
satisfy masticatory functional
requirements . both the anterior and
posterior teeth must function in harmony
with, and be anatomically and
physiologically compatible with the
surrounding oral environment.

4. I-anterior teeth selection
1-maxillary anterior teeth:
there are three basic considerations when
selecting the maxillary anterior teeth. These
are size, form and shade.

5. A- size of anterior teeth
four anatomic landmarks are used as guide for the
selection of the size of anterior teeth.
1-size of face:
the average width of the maxillary cental incisor is
estimated to one sixteenth(116) of the bi-
zygomatic width. The combined width of the six
maxillary anterior is slightly less than one third
(13) of the bi-zygomatic width of the face. The
face-bow can be used as a caliper to record the bi-
zygomatic width of the face.

6. 2-The cuspid eminences:
After the occlusal rim has been properly
contoured for esthetic, the approximate
location of the cuspid eminence (the apex of
the upper natural canine) can be determined
by extending parallel lines from the lateral
surfaces of the ala of the nose, corners of
the mouth onto the labial surface of the
upper occlusion rim. The distance between
the two marks following the contour of the
arch is the combined width of the six
maxillary anterior teeth.

7. 3-the vertical distance between the ridges:
the length of the teeth is determined by the
available space between the existing ridges,
when space is available, it is more
esthetically acceptable to use a tooth, long
enough to eliminate the display of the
denture base.

8. 4-the lip:
when the lips are relaxed and apart, the labial surface of the
maxillary anterior teeth should support the upper lip.
Frequently the incisal edges of maxillary anterior teeth
extend inferior to or slightly below the lip margin. During
speech, the incisal edge of the maxillary anterior teeth
contact the lower lip at the junction of the moist and dry
surfaces of the vermilion border. This is best demonstrated
when the letter f is pronounced by the patient. The
properly contoured maxillary occlusion rim should include
this position as the incisal edge position that will aid in
determining the length of the teeth . also, the lower lip line
and the high lip line marked on a properly contoured
occlusion rim aid in determining the length of maxillary
anterior teeth.

9. B-form of the teeth
three factors are used as guides in the selection of the
form of the anterior teeth:
1-the form and contour of the face:
the general outline form of the tooth should conform
to the general outline of the face when viewed
from the frontal aspect. Also a tooth viewed from
the mesial and distal aspect should conform to the
contour of the facial profile.

10. A-the general outline of the face:
it can be grouped into square, tapering, ovoid or combination.
This can be determined by, imagining two lines on either
side of the face running about 2.5 cm in front of the tragus
of the ear and touching the angle of the mandible,
1-if these lines are parallel of the face is square.
2-if they converge towards the chin the face is tapered
3-if they diverge away from the chin, the face is ovoid.
B-the facial profile:
)to determine the facial profile observe the relative
straightness of curvature of the profile). The labial surface
of the teeth should be in harmony with the facial profile. If
the face presents a curved profile than a tooth should be
selected to harmonize with that profile.

11. 2-sex
curved facial features are always associated
with femininity, while square features are
always associated with muscularity. There
for , the teeth of females are more ovoid or
tapered rather than square , those for males
are usually square.

12. 3-shape of the dental arch
The form of central incisors should not only
harmonize with the form of the face but also
with the form of the dental arch. Patients
with predominantly square dental arches
often have square teeth. The same principle
of the harmony apply to the square tapering
and ovoid types, i.e. V-shaped arch is
associated with incisors that are narrower at
the neck than at the incisal edge.

13. C-color or shade of anterior teeth
1-the color of the teeth, like the form must be in
harmony with the surrounding environment if they
are to appear natural. Harmony should exist
between the color of the teeth and the color of the
skin, hair and eyes.
2-the patient's age:
The color of natural teeth change with age they get
progressively darker as a result of deposition of
secondary dentine. The general rule is that darker
teeth are more suitable for old patients while,
lighter teeth are suitable for young patients.

14. Most of natural teeth have the following
characteristics:
A- the neck of the tooth have a more pronounced
yellow color than incisal third.
B-the incisal edge is more translucent than the body
of the tooth because it is composed entirely of
enamel.
C-the upper central incisors are the lightest teeth in
the mouth. The upper lateral ,lower centrals and
laterals are slightly darken. The upper and lower
canines are more dark.
D-teeth darken slightly with age.

15. 2-mandibular anterior teeth
Selection of the lower six anterior teeth is
relatively a simple procedure. Each set of
the upper anterior teeth has a corresponding
set of lower anterior teeth which match in
the size, form, and color.

16. II-posterior teeth selection
The selection of posterior teeth involves
shade, size, number and form:
A-shade of posterior teeth:
the shade of posterior teeth should harmonize
with the shade of anterior teeth.

17. B-size and number of posterior teeth:
the posterior teeth must support the cheeks and
tongue and function in harmony with musculature
in swallowing, speaking and mastication.
1-the buccolingual dimension:
Of the artificial teeth should be less than that of
natural teeth to reduce the size of the occlusal
table, and stresses transmitted to the underlying
supporting structures. This will also permit forces
from the cheeks and tongue maintain the dentures
in their position or the residual ridge. However,
this reduction should not be accomplished at the
expense of losing support for the cheek.

18. 2-the anteroposterior dimension:
Of posterior teeth is determined by the edentulous between
the distal surface of the canine and the ascending are of the
mandible which is usually situated slightly anterior to the
retro molar pad. Placing teeth on the ascending area of the
mandible will direct the masticatory forces at an inclined
plane. Forces directed at an inclined plane are more
dislodging than forces directed at right angles to the
supporting structure.
3-the vertical length:
Of posterior teeth depends on, the available interarch distance
and the length of anterior teeth. The length of maxillary
first premolars should be comparable to that of the
maxillary canines to have proper esthetic effect.

19. c- form of posterior teeth:
the form of occlusal surface of posterior teeth
may be classified according to their cuspal
inclination into:
I-anatomic form
II-non anatomic form.

20. I-anatomic form
The anatomic form has cusps, grooves and inclined planes . the cusp
angle ranges from 20-45 with average 33.
II-the non anatomic form:(cuspless or flat teeth(:
Has flat occlusal surface with shallow grooves and no cusps.
Selection of a suitable form of posterior teeth depends on individual
requirements.
The anatomic forms of posterior teeth are commonly used for patients
having normal ridge relations and well developed ridges.
Non anatomic form; however, may be used in the following condition:
A- cross-bite ridge relation. In this condition, the lower posterior teeth are
in a buccal relation to the upper posteriors which is the reverse of that
in normal ridge relation.
B-cases suffering from T.M.J. disturbances.
C-in nervous or hysterical patients, or in patients where neuro-muscular
coordination has been lost.
D-in cases with advanced ridge resorption.

21. Tooth material
Artificial teeth may be made from:
1-acrylic resin
2-porcelain
3-metal

22. 1-acrylic resin teeth
Properties of acrylic teeth:
A-acrylic teeth unite with the denture base resin by chemical union, they
can be used in cases having insufficient inter-arch distance.
B-they are less harmful to the underlying tissues because of their great
resilience.
C-they have low specific gravity(light in weight), and can be easily
modified by grinding.
D-acrylic resin posterior teeth are used when oppose natural teeth or teeth
whose occlusal surface have been restored with gold. This reduces the
possibility of the artificial acrylic teeth, causing unnecessary abrasion
and destruction to the opposing natural or metallic occlual surfaces.
Acrylic resin teeth have low co-efficient of wear than gold and
enamel.
E-acrylic resin teeth on the other hand may become worn up with
consequent loss of the established occlusal vertical dimension

23. II-porcelain teeth
1-Properties of porcelain teeth:
Porcelain teeth unite to the denture base by mechanical means, anterior
porcelain teeth have pins in their lingual surfaces while posterior teeth
have holes in their under surfaces. The pins and holes act as a retentive
device for mechanical union with the denture base.
2-porcelain teeth have high degree of abrasion resistance and therefore
maintain their luster longer than acrylic resin teeth and preserve the
established occlusal vertical dimension.
3-porcelain teeth are brittle, and thus susceptible to fracture.
4-the under surface of porcelain teeth cannot be ground much of fit
limited inter-arch distance without losing their retentive device.
Further more, any occlusal grinding must be followed by careful
polishing in order to reduce the co-efficient of friction.

24. The combined use of porcelain teeth in the maxillary
denture occluding with acrylic teeth in the
mandibular denture has the following advantages:
1-sharp impact sound of porcelain teeth is reduced
2-chipping and fracture of porcelain teeth is reduced.
3-the occlusion can be easily adjusted by grinding
only the acrylic teeth.
4-the efficient sharp cusps are retained.
5-as long as the glaze on the porcelain remains
intact, a good quality acrylic teeth can resist wear,
thus maintaining the vertical dimension.

25. Tooth arrangement
Factors governing the position of artificial teeth:
I-anterior teeth:
Anterioposterior positioning of anterior teeth is
important for esthetic and phonetic because of the
support that teeth give to lips. Therefore it is
important to place anterior artificial teeth in the
same position or in a position as close as possible
to that occupied by natural teeth to maintain
proper support of these tissues and natural patient
appearance

26. The crest of the residual ridges aids in positioning
the artificial teeth if the natural teeth are recently
extracted. As resorption progresses, the crests of
the residual ridges do not remain in their relative
position, due to the pattern of alveolar bone
resorption. The loss of bone structure is usually
greater on the buccolabial aspect of the maxillary
ridge than one the palatal aspect. As a result the
crest of residual ridge becomes more palatal than
it was prior to extraction of the teeth. For this
reason the incisive papilla is used as a useful
anatomic guide in determining the anterioposterior
and mediolateral position of maxillary anterior
teeth, because of its constant relationship to the
natural teeth.

27. A line drawn on the cast anterioposteriorly
bisecting the midsagital suture, incisive
papilla and the labial frenum coincide with
the midline of the upper dental arch.
Mediolaterally, the central incisors are set
on either side of this line.
Anterioposteriorly, the central incisors are
positioned so that the distance from the
center of the incisive papilla to the labial
surface of the central incisors is about 8-10
mm.

29. II-posterior teeth
Posterior teeth are generally placed to enhance the
stability of the mandibular denture. This is done
by arranging the teeth, so that the mandibular
posterior teeth are over, or slightly lingual to the
crest of the mandibular residual ridge.
The retromolar pad is used as a guide in determining
the buccolingual position of posterior teeth, a line
drawn from the center of the retromolar pad to the
canine area, marks crest of the mandibular ridge

31. Arranging the maxillary anterior
teeth
To establish points of reference to the correct
arrangement of the teeth, extend the midline
and the cuspid line on both sides to the
margins of the cast and the mounting
plaster. The midline coincides with the
contact point between the two central
incisors.

32. Procedure:
1-remove a small section of wax from the
occlusal rim, corresponding to the position
of the maxillary left central incisor from the
occlusal rim. Then soften the wax where the
occlusion rim has been cut away with a hot
spatula until the wax pools.

33. The maxillary central incisor is placed in this
position, so that,
1-its mesial surface coincides with the midline.
2-its long axis shows a slight distal inclination to the
sagittal plane or to the perpendicular.
3-the incisal edge is on the occlusal plane.
4-the neck of the tooth should be slightly depressed.
However the facial surface of the tooth is nearly
perpendicular to the occlusal plane.
5-in a similar manner, place the adjacent central
incisor to preserve the midline.

34. 2-place the lateral incisors following the same procedure, so that,
1-the incisal edge is raised approximately 12,1mm from the occlusal
plane.
2-its long axis shows more distal inclination than the central incisors.
3-the neck is depressed more than the central incisors.
4-the facial surface is in the line with the central incisors
3-place the maxillary canines in place, following the same procedure so
that,
1-the long axis is almost vertical or it may have a slight distal inclination.
2-the incisal tip is on the occlusal plane.
3-the neck is prominent in order to support the corner of the mouth.
4-the distal surface of the canine is rotated in a posterior direction with
the crest of the posterior alveolar ridge i.e. the canine is the turning
point of dental arch . normally when positioned properly the
mesiolabial aspect of the canine will be visible from the anterior view.
5-remove excess wax on the palatal surface with hot spatula.
6-examine the anterior teeth from- the occlusal aspect, the facial surfaces
of the teeth should follow the original contours of the dental arch.

37. Arranging the mandibular anterior
teeth
Following the same procedures,
1- the mandibular central incisors :
are placed with their long axis perpendicular to the
occlusal plane with the necks depressed
2-the mandibular lateral incisors:
Are placed with a slight distal inclination at the neck
and with the facial surface at a right angle to the
occlusal plane.

38. 3-the mandibular canines:
1-Are placed with amore distal inclination and the necks are
prominent.
2-the distal incline of the maxillary canine should occlude
against the mesial incline of the mandibular canine.
3-the distal surface of the canine is rotated in a position
direction to form the turning point of the dental arch.
4-the horizontal plane used for aligning lower anterior teeth is
above the actual occlusal plane, a distance described as the
vertical overlap or overbite, which consequently affects the
incisal guidance
5-the mandibular incisors should never touch the maxillary
incisors in centric occlusion and the incisal guide angle
should be kept as low as possible to enhance free
movement of the teeth in protrusive and lateral excursions.

41. Arranging the posterior teeth
To determine the buccolingual position of posterior
teeth, mark the crest of the mandibular ridge from
the center of the retromolar pad to the canine area
on both sides.
-extend this line to the land area of the cast at the
anterior and posterior borders on both sides.
-mark a line on the occlusion rim corresponding to
the line drawn on the crest of the ridge.
This line serve as an aid in checking the alignment
and position when setting the maxillary posterior
teeth.

42. a-arranging the maxillary posterior teeth:
maxillary first premolar:
a position of wax is removed, the remaining wax is softened and the
maxillary first premolar is placed in position so that:
1-the bucall surface of the first premolar harmonized with the canine.
2-both buccal and the palatal cusps are on the occlusal plane. The palatal
cusp lies over the line on the occlusal rim, representing the crest of
mandibular ridge.
3-the long axis of the tooth is at right angle to the occlusal plane.
Maxillary second premolar:
Place the maxillary second premolar so that:
1-its long axis is at right angle to the occlusal plane.
2-the buccal and palatal cusps are on the occlusal plane.
3-the palatal cusp is over the crest of the lower ridge.
4-the facial surface of the second premolar harmonizes with that of the
first premolar and canine i.e. forming a straight line.

43. Maxillary first molar:
Place the maxillary first molar so that:
1-its long axis has slight mesial inclination at the
neck.
2-the mesio-buccal cusp is slightly off the occlusal
plane. The distobuccal is slightly a greater off the
plane. The mesio-palatal cusp is on the plane. The
distopalatal cusp is slightly off the plane
3-the mesio-buccal cusp should be aligned with the
two premolars.
4-the mesio-palatal is the only cusp touching the
plane.
.5-the palatal cusps lie over the crest of the lower
ridge.

44. Maxillary second molar:
1-place the maxillary second molar in a
similar manner. All cusps are raised from
the occlusal plane.
2-follow the same procedure in placing the
posterior teeth on the opposite side.

47. Arranging the mandibular posterior teeth:
In centric occlusion, the buccal cusps of
mandibular teeth fit into the central fossae
of the maxillary teeth while the lingual
cusps of the maxillary teeth fit into the
central fossa of the mandibular teeth. this
position establishes the proper buccal over
jet i.e. the buccal cusps of maxillary teeth
extend beyond the facial surfaces of the
mandibular teeth.

48. Mandibular first molar:
The mandibular first molar is the key-tooth in articulation and
setting of mandibular posterior teeth.
Procedure:
1-a section of the mandibular rim is removed to make room
for the mandibular left first molar. The wax is soften to
permit placement of the tooth.
2-the mandibular first premolar is placed in position. so that:
A-the mesiopalatal cusp of the maxillary first molar fits into
the central fossa of the mandibular first molar to establish
the proper buccal over jet, and the mesiobuccal cusp of the
upper first molar fits into the buccal groove of the lower
first molar.
b-the mesioplatal cusp of the upper first molar fits in the
central fossa of the lower and the mesiobuccal cusp of the
lower first molar fills the embrasure between the upper
second premolar and first molar

49. mandibular second molar:
following the same procedure. The mandibular second molar is positioned
so that, the mesiobuccal cusp of the maxillary second molar fits into
the buccal groove of the second molar, and the mesiobuccal cusp of
the mandibular second molar fits into the embrasure between the
maxillary first and second molar.
Mandibular second premolar:
Following the same procedure place the mandibular second premolar with
the tip of the buccal cusp fitting into the embrasure between the
maxillary second and first premolar and contact the mesial marginal
ridge of the upper second premolar
Mandibular first premolar:
In some instances there may not be sufficient space for the mandibular
first premolar, in such case grind the tooth mesially and distally until it
fits into the available space. The tooth is positioned with the tip of the
buccal cusp in contact with the mesial marginal ridge of the upper first
premolar
-following the same procedures , place the posterior teeth on the opposite
side.