Pontics

1. PONTICS.
Definition.
The pontic is the fixed partial denture component
that replaces the missing natural tooth to restore
function,esthetic and compatible with continued
oral health and patient comfort.
The pontic is attached to the retainer by a rigid
connector such as solder joint or nonrigid
connector in special cases such as key and
keyway.

2. Design
To peform proper pontic design careful analysis
of the dimensions of the edentulous area
(pontic space) mesiodistally,occlusocervically
and buccolingually also the form and shape of
the residual ridge must receive attention to
provide hygienic requirements and prevent
gingival irritation.

3. Pontic space.
Tilting or drifting of the adjacent teeth into the
edentulous space may occur reducing the
available space for the pontic,so repositioning
the abutments ortodontically when esthetics
is important or modification of the abutments
with complete coverage retainers is done.

4. Residual ridge contour.
An ideally shaped ridge will be smooth to
maintain plaque free.
Patients who have irregular hyperplastic
tissue,may need surgical removal of excess
fibrous tissue.
Bone resoption following tooth loss due to
trauma may be present;this will affect
aesthetic and biologic demands so;

5. a.)Augmentation with hydroxylapatite ships may
be one solution.
b.)Another solution is to create a roll of soft
tissue labial to the pontic site.

6. Pontic classification.
Pontic designs are classified into two general
groups; those that contact the oral mucosa and
those that do not.
Pontic selection depends primarily on esthetics
and oral hygiene.
In anterior region where esthetics is a concern
the pontic should be well adapted to the tissue to
make it appear that it emerges from the gingiva.

7. • In the posterior region (mandibular premolar
and molar areas),esthetics can be
compromised in the interest of designs that
are more amenable to oral hygiene.
1.) Sanitary pontic.
The primary design feature of the sanitary
pontic allows easy cleaning because its tissue
surface remains clear of the residual ridge.

8. • A modified version of the sanitary pontic has
been developed.
• Its gingival portion is shaped like an archway
between the retainers.
• This geometry permits increased connector
size while decreasing the stress concentrated
in the pontic and connectors.

11. 2.)Modified ridge lap pontic.
The modified ridge lap design overlaps the residual
ridge on the facial surface (to achieve the
appearance of a tooth emerging from the gingiva)
but remains clear of the ridge on the lingual
surface.
To enable optimal plaque control , the gingival
surface must have no depression rather it should
be as convex as possible from mesial to distal(the
greater convexity ,the easier the oral hygiene).

12. • Tissue contact should resemble a letter T
whose vertical arm ends at the crest of the
ridge.

14. 3.)Conical pontic.
Often called egg-shaped,bullet-shaped or heart-
shaped, the conical pontic is easy for the patient
to clean.
It should be made as convex as possible ,with
only one point of contact at the center of the
residual ridge.
This design is recommended for the replacement
of mandibular posterior teeth where esthetics is
a lesser concern.

16. • The facial and lingual contours are dependent
on the width of the residual ridge, a knife-
edged residual ridge will necessitate flatter
contours with a narrow tissue contact area.
• If used with a flat ridge, large triangular
embrasure spaces around the connectors will
result leading to food impaction.

17. 4.)Ovate pontic.
Is the most esthetically appearing pontic
design.
Its convex tissue surface resides in a soft
tissue depression or hollow in the residual
ridge ,which makes it appear that a tooth is
actually emerging from the gingiva.

18. • Socket-preservation techniques should be
performed at the time of extraction to create
the tissue recess from which the ovate pontic
form will emerge.

20. Biologic principles of pontic design
• This pertains to maintenance and preservation
of the residual ridge, abutment and opposing
teeth and supporting tissues.
• Factors of specific influence are:
1. Pontic ridge contact
2. Amenability to oral hygiene
3. Direction of occlusal forces

21. 1. Ridge contact
• Pressure – free contact between the pontic and the underlying
tissue is indicated to prevent ulceration and gingival inflammation.
• If any blanching on the gingiva is observed at try-in, the pressure
area should be eliminated until tissue contact becomes passive.
When the pontic rests on the mucosa, some ulceration may appear.
• In the anterior region of the mouth where esthetics is important,
the pontic should contact the gingival tissue on the labial or buccal
surface to give a more natural appearance. Special care must be
paid to the gingival surface of the pontic to prevent tissue
impingement and ulceration at the contact area.
• In the posterior region, more attention should be paid to occlusion,
function and hygiene.

22. • According to the shape of the gingival surface and its
relationship with the underlying mucosa, the pontic
may be classified into two groups:
a. Mucosal contact
i. Ridge lap
ii. Modified ridge lap
iii. Ovate
iv. Conical
b. Non – mucosal contact
i. Sanitary( hygienic)
ii. Modified sanitary ( hygienic)

25. • With mucosal contact types, the excellent
hygiene habits must be developed by the patient,
and the use of proxy brushes, pipe cleaners,
super floss and dental floss are highly
recommended.
• The pontic that overlaps the buccal and lingual
sides of the residual ridge is called saddle shaped
pontic, should be avoided because of its concave
gingival surface which cannot be easily cleaned
by the patient.

26. 2. Dental plaque
• The main cause of ridge irritation is the release of
toxins from microbial plaque which accumulate
between the gingival surface of the pontic and
the residual ridge.
• To enhance plaque control, the patient must
perform efficient oral hygiene techniques
especially on the gingival surface of the pontic.
• The shape of the gingival surface of the pontic, in
relation to the ridge and the material used for
pontic fabrication will affect dental plaque
control.

27. 3. Pontic materials
• The materials used should provide good esthetics
when needed, biocompatibility, rigidity, strength to
withstand occlusal forces and longevity.
• FPDs should be as rigid as possible because any flexure
during mastication or Para function may cause pressure
on the gingiva and cause fractures of the veneering
material.
• Occlusal contacts should not fall on the junction
between metal and porcelain during centric or
eccentric tooth contacts , nor should a metal ceramic
junction occur in contact with the residual ridge on the
gingival surface of the pontic.

28. • Two important factors in biocompatibility of materials:
i. The effects of the materials
ii. The effects of surface adherence
• Glazed porcelain- generally considered the most
biocompatible of available pontic materials. The critical
factor is the material’s ability to resist plaque accumulation.
• Well polished gold- smoother, less prone to corrosion, less
retentive of plaque than unpolished or porous casting.
• Although glazed porcelain looks very smooth, under a
microscope, its surface shows many voids and is rougher
than polished gold or acrylic resin. Nevertheless, highly
glazed porcelain is easier to clean than other materials.

29. 4. Occlusal forces
• Reducing buccolingual width of the pontic by as much
as 30% has been suggested as a way to lessen occlusal
forces on and thus the loading of abutment teeth. This
practice continues today, though with little scientific
basis.
• Critical analysis show that forces are lessened only
when chewing food of uniform consistency. Potentially
harmful forces are more likely to be encountered if a
FPD is loaded by accidental biting on a hard object or
parafunctional activities like bruxism. These forces are
not reduced by narrowing the occlusal table.

30. • In some cases, narrowing the occlusal table
may impede or preclude the development of a
harmonious and stable occlusal relationship.
Like in a malposed tooth, it may cause
difficulties in plaque control and may not
provide proper cheek support. This is why
pontics with normal occlusal widths on the
occlusal thirds are recommended.

31. MECHANICAL PRINCIPLES

32. • Its influenced by
• Choice of material
• Tooth preparation
• Framework design
• Occlusion
• Interference of the above factors will result to
fracture of the restoration or displacement of
retainers

33. Long-span posterior FPDs are particularly susceptible to
mechanical problems. There is significant flexing from high
occlusal forces and because the displacement effects
increase with the cube of the span length . Therefore,
evaluating the likely forces on a pontic and designing
accordingly are important. For example, a strong all-metal
pontic may be needed in high-stress situations rather than
a metal-ceramic pontic , which would be more susceptible
to fracture. When metal-ceramic pontics are chosen,
extending porcelain onto the occlusal surfaces to achieve
better esthetics should also be carefully evaluated. In
addition to its potential for fracture, porcelain may abrade
the opposing dentition if the occlusal contacts are on
enamel or metal.

34. Available pontic material
• 1-prefabricated porcelain pontis; once used
but are no longer used
• 2-metal ceramic pontic;is strong easy to clean
and natural appearing

35. • 3-resin veneered pontics; used as long term
restoration because they have low abrasive
resistance, they have dimensional change due
to low water absorption and thermo cycling.
The resin must be retained to underlying
metal by mechanical means due to its
dimensional change
• Leakage may occur leading to discoloration
and failure of bond

36. Advantages of resin
• Easy to manipulate
• Easy to repair
• Do not require high melting range alloys that
are needed for metal ceramic

37. • 4-fiber reinforced composite resin pontics
• It can be used without a metal substracture.
The substructure matrix of impregnated glass
or polymer fiber provides structural strength
• It has good marginal adaptation and esthetics.

38. 2;PROPER FRAMEWORK DESIGN
• 2. The metal surfaces to be veneered must be smooth and free of
pits. Surface irregularities will cause incomplete wetting by the
porce lain slurry, leading to voids at the porcelainmetal interface
that reduce bond strength and increase the possibility of
mechanical failure.
• 3. Sharp angles on the veneering area should be rounded. They
produce increased stress concentrations that can cause mechanical
failure.
• 4. The location and design of the external metalporcelain junction
require particular attention.Any deformation of the metal
framework at the junction can lead to chipping of the porcelain .
For this reason, occlusal centric contacts must be placed at least 1.5
mm away from the junction. Excursive eccentric contacts that might
deform the metalceramic interface must be watched carefully.

39. ESTHETIC PRINCIPLES
• An esthetically successful pontic will replicate
the form, contours, incisal edge, gingival and
incisal Embrasure
• Special attention should be paid to the
contour of the labial surface as it approaches
the pontic-tissue junction to achieve a
"natural" appearance.

40. • This cannot be accomplishedby merely
duplicating the facial contour of themissing tooth,
because after a tooth is removed, thealveolar
bone undergoes resorption and/or remodeling.If
the original tooth contour were followed,the
pontic would look unnaturally long
incisogingivally. To achieve the illusion of a
naturaltooth, an esthetic pontic must deceive
observers into believing they are seeing a natural
tooth.

41. • LIGHT AND SHADE;In normal situations, light falls from
above, and an object's shadow is below it. Unexpected
lighting or unexpectedly placed shadows (Fig. 20-33)
can be confusing to the brain. Because of past
experience,the brain "knows" that a tooth grows out
of the gingiva,and it therefore "sees" a pontic as a
tooth unless telltale shadows suggest otherwise.
Special care must be taken when studying where
shadows fall around natural teeth, particularly
around the gingival margin. If a pontic is poorly
adapted to the residual ridge, there will be an
unnatural shadow in the cervical area that looks odd
and spoils the illusion of a natural tooth

42. Correct incisogingival height is critical to esthetic
pontic design. A, Esthetic failure of a four-unit FPD
replacing the right central and lateral incisors. The
pontics
have been shaped to follow the facial contour of
the missing
teeth, but because of bone loss they look too
long.
B, The replacement FPD. Note that the gingival
half of each
pontic has been reduced. Esthetics is much
improved.
C, This esthetic failure is the result of excessive
reduction.

43. • 2;propotion
• Teeth are considered to be propotional if all of
them are in proportion both the pontcis and
adjacent teeth
• 3-balance
• Position of midline should be placed properly

44. • with moderately severe bone resorption,obtaining a
natural appearance by exaggerated contouring of the
pontics may still be possible. In areas where tooth loss
is accompanied by excessive loss of alveolar bone,
however, a pontic of normal length would not touch
the ridge at all.One solution is to shape the pontic to
simulate a normal crown and root with emphasis on
the cementoenamel junction. The root can be stained
to simulate exposed dentin . Another approach is to
use pink porcelain to simulate the gingival tissues.
However, such pontics then have considerably
increased tissue contact and require scrupulous plaque
control for long-term success

45. Abnormal mesiodistal width
Edentulous space may be greater or smaller than
the width of the contralateral tooth,due to tooth
movement that occurred when a tooth was
removed and not replaced ,this should be
corrected by;
1;Orthodontic treatment
2;by changing the relative positions of the
mesiofacial and distofacial line angles and hence
the overall surface shape and contour and light
reflection between line angles