Pontics Flashcards
Although unpredictable, a greater amount of
alveolar ridge loss following extraction usually occurs
in the — dimension and affects the —
bone of the ridge.
In fact, –% of alveolar bone
dimension can be lost after tooth extraction, with
losses reported of up to —. Two-thirds of this loss
of bone volume can occur within the first —
months of tooth extraction.
horizontal
buccal
50
6–7 mm
three
Loss of — ridge height can also occur and usually
takes place along the — aspect of the ridge to a
— degree than horizontal ridge loss. Corresponding
reductions in vertical ridge height ranging from — mm
have been noted. The combination of this resorptive
pattern results in a ridge that has moved in a
— direction and has atrophied vertically.
vertical
buccal
lesser
2–4
palatal/lingual
Sockets that were preserved with bone
grafting and/or membrane on average lost —
mm less of ridge width, — mm less of ridge
height, and had —% more bone volume when
compared to sockets that were not
grafted. — sites lost more than
— sites, and most ridge resorption
occurred on the buccal aspect of the ridge.
2
1
20
Maxillary, mandibular
The Edentulous Ridge – Classification of Deformities
Class I:
Class II:
Class III:
Normal:
F-L Width (32%)
O-G Height (3%)
F-L and OG Height (56%)
(8%)
skipped
Pre-Treatment Assessment
Evaluate
(3)
Evaluate the dimensions of the
Edentulous space
Evalutate the positions of the abutment
teeth to assess the favorability for a bridge
Evaluate the possible occlusal outcomes
Evaluate the dimensions of the
Edentulous space
Evalutate the positions of the abutment
teeth to assess the favorability for a bridge
Evaluate the possible occlusal outcomes
Is there a need to reposition the teeth
orthodontically prior to fixed work?
— up is key to answer these questions
before you begin treatment
Diagnostic Wax
What Materials are used for Pontics?
(3)
Cast Metal
Metal-Ceramic
(Many configurations)
Zirconia or
All Ceramic
When two materials are
used, the finish line for their
joining should not be on
the
edentulous ridge.
What are the ideal characteristics we look for in a
pontic design?
(3)
Esthetic
Biologic
Mechanical
Esthetic
(2)
-Appearance of replacement
-Replication of “emergence” from ridge
Biologic
(4)
-Ability for the patient to clean well around
the bridge/pontic area
-Allows for healthy tissue
-Patient comfort of bridge
-Harmonious occlusion
Mechanical
(1)
-Rigid framework to resist deformation or
fracture
Esthetic Considerations
Ideally, a pontic should have the same — height as the original or
neighboring tooth.
When resorption of the bone has taken place, the pontic changes shape in order to
keep in contact with the —
Contour needs to be blended smoothly to avoid a ledge at the cervical.
inciso-gingival
ridge concavity
Esthetic Considerations
Contour in — should approximate the length of the adjacent teeth
The facial surface is altered to curve gently from the
Apical ½
gingival-facial to the middle of the
facial surface
Esthetic Considerations
Ideally, the pontic should adapt to the ridge well
When the pontic does not adapt well, (3) can
become troublesome
esthetics, speaking, and food impaction
Biological Considerations
Pontic ridge contact should ideally be on — tissue. When on non-keratinized tissue,
(2) can occur.
Pontic contact with ridge should not inflict — on the tissue.
Contact with the — should be minimal. Pontic shape in contact with tissue should also be —
keratinized
ulceration and constant irritation
pressure
tissue, convex
Delicate balance of light to slight tissue contact
-Contact too heavy?
-Contact too light?
Contact area should be small and shape of pontic convex
Tissue/bone resorption
Food impaction, esthetics compromised
Biological Considerations
Convex shape of gingival aspect of pontic allows for
easier cleaning for patient
“Fullness” of pontic shape and proper gingival embrasures block out and keep food
and debris from being trapped under pontic.
Biological Considerations
Oral Hygiene
(5)
Floss Threader
Super Floss
Proxabrush
Rubber Tip
Water Pik
Physical Considerations – Strength
Pontic connectors need appropriate size to be strong
— Occlusal-Gingivally
— Facial-lingually
4mm
3-4mm
Material Strength
Metal > Zirconia > Porcelain > Acrylic
Pontic connectors should not impinge on –
embrasures
Physical Considerations – Position
Pontics placed outside of the
inter-abutment axis creates
torque on the connectors and
abutments which can lead to
failure
Recall that — is the biggest reason why we see mechanical failure in
bridgework. So replacing as ideal occlusion as possible extends the life of the
restoration.
occlusion
Physical Considerations – Occlusion
Occlusion development with a bridge should replace ideal occlusion
MI contacts, Working and Non-Working contacts in lateral excursions, Protrusive
contacts, and canine guidance
Ridge Lap
-Also known as a — pontic
-Not used any longer
-Forms a large — contact area with ridge
-Patient not able to —
-Creates
Saddle
CONCAVE
clean
tissue inflammation leading to tissue ischemia and necrosis
Hygenic Pontic
-Also known as – Pontic
-No contact with –
-at least — of space between the
ridge and the pontic
-Patient can easily clean without the
pontic being a —
-Only for use in —
-Design and shape is — in all
directions.
Sanitary
Ridge
2-3mm
food trap
non-esthetic areas
CONVEX
Pontic Design
– Modified Hygenic Pontic
-Perel Modification
To increase — of
bridge in connectors with
hygenic pontic
— is increased
with less occlusal gingival
height. So, lets beef up
those connectors!
strength
Deflection
Conical Pontic
-Passive contact with —
-Rounded and cleansable
-Triangular embrasure space can
-Best suited for —
-Also not best for — areas.
ridge crest
trap food
thin mandibular ridges
esthetic
Modified Ridge Lap
-Passive contact — side of ridge crest
-Can appear very —
— tissue surface contact
-Used frequently in the — areas.
-Shape can help keep
— much easier for patients
facial
esthetic
Convex
esthetic
food from trapping
Cleansibility
Pontic Design – Modfied Ridge Lap Pontic
Convex in all directions except for
a small concavity on the lingual
side of the facial-gingival aspect
of the pontic
Pontic Design – Modfied Ridge Lap Pontic
Contact area is meant to be —
— side needs to be smooth
and highly polished
Tissue contact ok but should not
put — on the tissue.
Keep tissue contact on —
Tissue contact shape is ideally
shaped like a —
minimal
Lingual
pressure
Keratinized tissue
T
Pontic Design – Ovate Pontic
Blunt rounded Pontic shape that is set into a
— by well educated and motivated patients
Highly —
concavity in the tissue of the edentulous ridge
Cleansable
Esthetic
Pontic Design – Ovate Pontic
Generally requires planning
(3)
-Pre-Prosthetic surgery via immediate
provisionalization after extraction
-Surgery/modification with provisional to
develop tissue shape and contour
-Ovate Pontics keep a slight pressure on the
tissue to maintain the effect of
emerging from the ridge
— requires lots of planning, possible
surgery, and a patient willing to work to
clean and maintain the area.
Ovate
Modfied Ridge Lap then is the most
common type of pontic because it is
esthetic but requires much less effort on
the part of the doctor and patient.
Connector design is important for the — of the FPD.
strength
Connector design is important for the strength of the FPD.
Can be challenging to get appropriate —
with short or crowded dentition.
height and width
Typical Connector dimensions:
Height –
Width –
Gingival Embrasure form better to be
Consideration needs to be made to design an
appropriate cross-sectional area
3-4 mm
3-4 mm
U shaped than V shaped
Connectors are shaped to be concave in the
Buccal Lingual AND the Mesial Distal
TOWARD the ridge.
U shape from Occlusal to Gingival
(2)
-U shape is stronger than a V shape.
-U shape provides stronger fracture
resistance.
Remember… Minimum height is — mm
3-4
Remember… Minimum height is 3-4mm
-if you increase the height, you increase the
strength
-Height x2 = increased strength by a cube
Connectors are designed large enough to
prevent fracturing, but not to impinge on
embrasure and physiological contouring
Anterior connectors are placed more —
for esthetics
Anterior connectors are longer —
for strength
lingually
inciso-gingivally
Anterior connectors considered ”—
Drop” shape
Tear
Posterior Connectors
— height is more important
than — width for strength
Posterior connector shape is considered “—”
Getting appropriate 3-4mm height can be
challenging in some posterior
situations.
Occluso-Gingival, buccal-lingual
heart shaped
Connector size is at least — and possibly needs to
be larger
4mm
U shaped connectors need a large radius at the
gingival embrasure
Full strength Zirconia shows increased fracture
resistance compared to all ceramic, but as of yet,
research shows the need for connectors in size
similar to all ceramic
Strength is a challenge thus far and there is an
increased — potential with all ceramic
bridges
fracture
-Metal frameworks are assembled in two ways:
(2)
-Cast/milled as one piece
-Two or more pieces are soldered together (metal
only).
**(Laser Welding in Titanium alloy situations can be
used)
**(CAD/CAM can be used to make a one piece
bridge framework with ceramics/Zirconia)
Strength is a challenge thus far and there is an
increased — potential with all ceramic
bridges
fracture
(2) are still the standard that others
are measured against
PFM and Full Gold bridges
Single Piece casting issues to watch for:
-Distortion –
greater the length, the increased distortion
Can be very challenging to verify the fit of all the
retainers and therefore to over reduce the
interior/intaglio of the framework to get it to seat
fully
Due to these problems, often longer span bridges are cast in
multiple pieces and soldered together. The idea is that two small pieces are easier to fit than
one longer one.
Also, if an FPD metal framework you are trying in does not fit due to distortion, you can
cut between a
pontic and retainer, re-seat each smaller piece to
verify each individual fit, and then capture the new
seating with acrylic. This can be sent to the lab to
solder the two pieces together.
If your framework has distorted or you have two large
pieces of framework to try in, how do you reconnect
them? What is soldering and how is it done?
Soldering –
(3)
joining of metals by fusion of filler metal bonding
to each of the parts being joined.
-The bond is created by wetting the surface of parent
metals with liquified solder
-The metal framework does not melt during this
Brazing –
A specific form of soldering when the filler
material has a melting temperature above 450
degrees Celsius.
skipped
Dental Solder – What do we desire solder to do
for us?
(6)
-Resists tarnish and corrosion
-The fusion temperature 100-150 degrees Fahrenheit below
that of the substrate metal
-Free flows when melted
-Resists pitting
-Is strong
-Matches color of the two parts being joined.
How do we classify Solder? And WHY?
Solder is classified by Fineness
-Fineness is the parts per thousand of gold in a
solder
-650 fine =
Higher Fineness increases the
Higher Fineness increases
Higher Fineness results in
650 parts gold per thousand parts
melting range
resistance to tarnish or corrosion
decreased hardness
What factors affect the accuracy and
prognosis of soldered connectors?
(3)
- Connector Space
- Metal Surface Preparation
- Indexing Technique for Investment
Connector Space
A proper space between the two metal
surfaces allows the
solder to flow in-
between
A proper space allows for (2) of the solder
thermal expansion
and shrinkage
A proper space is small enough to minimize
distortion from the solder shrinkage as it
cools
A proper space is also large enough to allow
for a
strong connector
A proper space is
parallel and flat with a space
for thickness the size of a business card
(0.2mm)
Metal Surface Preparation
Metal Surface needs to be (2)
Metal Surface needs to have a — finish instead of
highly polished.
clean and uncontaminated
satin
Indexing Technique for Investment
2 steps
- Flow auto-polymerizing acrylic resin into space to hold two pieces together.
Each side should be fully seated with margin integrity checked and
verified. - Make an occlusal plaster index to send to the lab for soldering. Framework should be
solidly planted in plaster index so that enough of the coronal portion is covered so
framework can be held in place.
Flux –
Enables solder to wet and spread over clean
metal surfaces. Flux removes oxides, and
prevents further oxide formation
-contains Borate
Anti-Flux –
Limits the spread of the solder.
-Contains graphite or rouge
Pre-Ceramic Veneer Soldering
(5)
Uniting components of the same alloy
BEFORE porcelain is fired.
Uses high-fusing solder
Melt solder with a torch
Solder has lower melting temp than alloy,
but higher melting temp than porcelain
firing temperature
Less Technique Sensitive
Post-Ceramic Veneer Soldering
(7)
Uniting components of the same alloy AFTER
porcelain is fired
Uses low-fusing solder
Melt solder in oven
Solder has lower melting temp than alloy and
porcelain
More Technique sensitive
*Can compensate for slight discrepancies or
distortions that occur AFTER the porcelain is
fired.
*Porcelain can crack in area of solder joint
during solder process
Open Contact with a All metal or PFM
crown?
Addition Soldering –
Adding material to contact area
Smoothing and shaping contact area
Voila! Contact!
Can add contacts to Zirconia too but not
to Lithium Disilicate
