prosthodontics

2. Selection of teeth according to material
•Acrylic resin
•* porcelain
•*metals
•*combination between acrylic resin & teeth

3. Acrylic resin teeth
advantage
•Lighter in weight
•*can be modified by girding
& polishing (less hardness)
so can be used in close inter
arch space
•*chemical union with acrylic
denture resilient (absorb the
force)
•*used in flat & flabby cases
•*less noise in use
disadvantage
Wear easily duo to (less
abrasion resistance
•Easily distorted by heat
•*crazing may occur duo to
action of organic solvent if
not cross linked
•*less perfect esthetic)

4. Porcelain teeth
*difficult to be modified by girding
(remove the glaze) & polishing
(more hardness) so can not be
used in close inter arch space
*mechanical union with acrylic
denture less ( pins, holes & raised
dots resilient (transmitte more
force)
* not used in flat & flabby cases
*more noise in use
•brittle
•higher in weight
* Not wear easily duo to (more
abrasion resistance
* Not easily distorted by heat
*more resistant to the action of
organic solvent
*more perfect esthetic)
advantagedisadvantage

5. 1(Artificial teeth attached to denture bases by an
intermediate layer of acrylic resin:
allows for changing the position of teeth in the waxed-up
denture to produce natural appearance
Porcelain and acrylic resin teeth are produced in a wide variety of
shades, colour and forms that could perfectly match the
remaining natural teeth resulting in good esthetic
Porcelain teeth are mechanically retained to the denture bases.
→The posterior porcelain teeth are attached by acrylic resin in their
diatoric holes.
→The anterior teeth are attached by acrylic resin around retentive
pins located on the lingual surfaces of teeth.
→Acrylic resin teeth are retained by chemical union with the acrylic
resin covering metallic denture bases during laboratory processing

8. 2(Acrylic resin or porcelain facings cemented
to denture bases
Acrylic resin or porcelain facings are cemented to metal
backings. The metal backing forms the lingual half of the tooth&
is an extension from the partial denture framework
Tooth replacements in the form of facings are fabricated by the
laboratory and cemented by the dentist at the time of denture
insertion. This causes difficulty in obtaining
satisfactory occlusion and in providing adequate contours
Advantages of facings:
-Facings are inter-changeable and can be easily replaced.
•Disadvantages:
1-Facings have poor esthetic quality as they lack depth& give
a flat appearance.
2-The metal backing influences the shade of the plastic facing.
3-The opposing teeth may strike against the metal backings resulting
in rapid wear.
4-Adding a labial flange for the denture is difficult.
•Indications:
1-In restricted spaces exhibiting little horizontal overlap where
strength is of great concern.
2-In cases exhibiting minimal inter-occlusal space

9. REPLACED TEETH - ANTERIOR
Material:
Porcelain Acrylic
Acrylic denture
teeth on classs IV
RPD. The standard
denture tooth type
used for rpd’s and
cd’s at the U. Of M.
Porcelain denture teeth
are rarely used since
they are difficult to set.
Porcelain facings as
shown on left were used
for many years but not
now. The backing of the
facing is framework
metal with the facing
adjusted to fit the
buccal mucosa so no
acrylic is associated
with this area. The
facings can come off
during ultrasonic
cleaning so beware.
Source: Jeff Shotwell,
University of Michigan, 2008

11. 3(Tube teeth& Metal Post:
Tube teeth consist of either acrylic resin or porcelain denture
teeth which are prepared by drilling a channel from the base of the
tooth upwards to form a tube. They are usually used as single
tooth replacements, where a maximum of three teeth are used.
The metal partial denture framework should contain posts to which
tube teeth are cemented.
Disadvantages:
-Tube teeth are not strong replacements hence, they should not be
used when the mesiodistal or occluso-gingival space is restricted

14. 4(Reinforced acrylic pontic
RAP are new replacements which contain the good features of
facings and tube teeth and lack their short comings. They are made
of modern cross-linked copolymers which enable the dentist to
process acrylic resin teeth directly to the framework. The gingival
half of the lingual surface consists of metal projections or loops
around which the acrylic tooth is processed. The incisal half
is a solid, hard plastic which provides good esthetics and shade
control.
•Advantages:
-Better attachment to the metal base compared to cementation.
-Long, short, wide or narrow teeth could be created to fill edentulous
spaces that cannot
be easily filled by commercially available teeth.
-Occlusion on resin teeth may be re-established to compensate for
wear.

18. 5(Metal teeth
Metal teeth are usually used as replacements of posterior teeth
where space is limited for the attachment of an artificial tooth.
Second molars may be replaced as part of partial denture
casting as a space filler to prevent migration of an opposing
second molar.
.
•Disadvantages:
a- Metal teeth are esthetically unsatisfactory.
b- Difficult to attain any occlusal adjustment.
c- Metal teeth are abrasion resistant, hence occlusal
contact should be held to a minimum to avoid damage
to the periodontium of the opposing teeth.

20. Maxillary cast molar designed as integral part of
framework. Interocclusal space limitation necessitated using
metal rather than another form of artificial posterior teeth.
Note overlays on premolar and molar teeth used to resist
tooth wear.

21. mbination between acrylic resin & teeth
For decreasing the wear of the resin teeth and
preserving a degree of their resiliency and to
combine the advantage of both acrylic resin & metal
teeth.
Porcelain or resin backed with metal

23. REPLACED TEETH - POSTERIOR
- Material:
Acrylic posterior
denture teeth -
standard tooth used
on rpd’s and cd’s.
Much easier to set
and adjust than
porcelain. Clinical
wear helps dissipate
occlusal forces.
Gold occlusal surfaces
added to acrylic
denture teeth
opposite fixed partial
denture gold occlusal
surfaces to even out
wear potential
Occlusal chrome
surfaces on this
maxillary class III
RPD are an
extension of the
framework. Acrylic
facings are placed
on the buccal for
esthetics.
Note- Not used very
Source: Jeff Shotwell, University of Michigan, 2008

25. 6(Replacements with chemical bonding:
Recent developments provide means of direct chemical bonding of
acrylic resin to metal frameworks without using loops, mesh or
mechanical locks.
The section of the metal framework to support the teeth is
roughened with abrasives,
treated with vaporized silica coating then a resin bonding agent is
applied to which a thin film of resin is added for later attachment
with acrylic resin teeth