Pontic design / orthodontic straight wire technique
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Published on: Mar 4, 2016
Transcripts - Pontic design / orthodontic straight wire technique
INDIAN DENTAL ACADEMY
Leader in continuing dental education
• Pre treatment assessment
• Properties required of a pontic
• Pontic design
• Prefabricated pontics
• Pontic classification
• Pontic modification
• Available pontic materials
• References www.indiandentalacademy.com
• Name pontic is derived from latin word, ‘PONS’
• It is an artificial tooth of a fixed partial denture that
replaces missing natural tooth.
• It is not a simple replacement, because placing an
exact anatomic replica of the tooth in the space would
be hygienically unmanageable.
• Design of the prosthetic tooth will be dictated by
esthetics, function, ease of cleaning, maintenance of
healthy tissue on edentulous ridge and patient
• The pontic is a suspended member of fixed partial
denture which replaces the lost natural tooth, restores
function and occupies the space of the missing tooth.
• An artificial tooth of a fixed partial denture that
replaces a missing natural tooth, restores its function
and usually fills the space previously occupied by
1. Pontic space : One function of pontic is that it
prevents tilting or drifting of adjacent tooth into the
If tilting has occurred then orthodontic repositioning
is required because smaller pontic is unacceptable &
2. Residual ridge contour : Ideally ridge should be
smooth, regular surface with attached gingiva, which
facilitates maintenance of a plaque free
Its height and width should allow placement of a
pontic that appears to emerge from ridge and mimics
appearance of neighboring tooth.
Siebert’s classification of residual ridge deformity:
• Class 1: faciolingual loss of tissue width with normal
• Class 2 : loss of ridge height with normal ridge width.
• Class 3 : Combinations of loss in both dimensions.
• Class ‘n’ : minimal deformity
1. The Roll technique:
It uses the soft tissue from lingual side of edentulous
side. Epithelium is removed, the tissue is thinned
and rolled back upon itself, thereby thickening the
facial aspect residual ridge.
2. The pouch technique:
Pouches are prepared on facial aspect of residual
ridge, into which sub epithelial or sub mucosal grafts
harvested from palate or tuberosity is inserted.
3. Class 2 and 3 defects:
a) Interpositional grafts:
In this, wedge shaped connective tissue graft is
inserted into a pouch preparation on facial aspect of
b) Onlay graft :
Thick free gingival graft is harvested from partial or full
thickness palatal donor site.
Allen’s modification :
1. Mild : less than 3 mm.
2. Moderate : 3-6 mm.
3. Severe : more than 6 mm.
Properties required of a pontic
2. Good esthetics
3. Color stability
5. Non irritant to soft tissue
6. Should not overload abutment toothwww.indiandentalacademy.com
Factors to be considered while designing a pontic :
1. Intrproximal embrassure : should be large for
2. Tissue covered : should be kept small on buccal
aspect for esthetic reasons.
Cantilever bridge is ideal to keep it clean, by passing
the floss easily by patient.
3. Occlusal surface :
- It should roughly correspond to the tooth it replaces.
- In posterior side, should be confined within the
margins of abutment teeth.
- It is better to reduce 20% width to reduce torque on
retainers and abutments.
-angulations of cusps depend on opposing teeth and
4. Tissue contact :
-Ideally, should be glazed porcelain. If it cant be done,
then gold should be used. Acrylic causes gingival
irritation and calculus deposition.
-A junction of two different materials on fit surface
should be avoided.
-Pontic should always have to be in approximately 0.2
mm. ,on the model.
-Space between pontic and mucosa is 0.1mm or less.
5. Length of span :
-Longer the span of pontic area, greater will be stress
on the pontic and solder joints should be stronger.
6. Relationship of ridge form and pontic :
-Sharp ridge is favorable because it is self cleansing.
-Flat ridge is difficult for hygiene maintenance, mainly
in closed bite and when vertical height is less.
They are classified according to mode of retention
employed for facing.
3. Cores and posts
4. Bonding to the metal
5. Mechanical locking
1. Retention by rails :
It is of 2 types-
a) Vertical line of insertion- Steeles slotted pontic
b) Horizontal line of insertion- Trupontic
a) Vertical insertion :
>There is a rail on to which is slotted a porcelain
facing. Gold is added to the backing on its lingual
aspect so as to reinforce it and produce correct
>It is relatively fragile facing because porcelain is
weakened by slot cut and also it is impossible to
protect incisal edge.
b) Horizontal insertion :
> It is of 2 types-
• Gold occlusal surface & porcelain at tissue surface-
• Porcelain occlusal surface & gold at tissue surface-
Steeles all porcelain.
• It is mainly used in the posterior region.
1. It has horizontal line of withdrawal.
2. Occlusal surface is protected by gold.
3. Tissue contact is achieved by porcelain.
1. Unsuitable when vertical dimension is less.
• Steeles all porcelain occlusal pontic :
> Aesthetically it is pleasing but fragile and should
only be used when bite is favorable.
: 2. Retention by pins
-It is most versatile of manufactured facings.
-Most popular form is long pin pontic in which pins are
taken right through the gold and riveted on its lingual
aspect, thus providing positive retention.
>It permits good thickness of gold on occlusal surface
and all porcelain on tissue surface.
>It can be used in closed bite cases or if spaces is
>Its failure rate is less and can be used where
Trupontic cant be used.
3. Cores and posts :
a) Cores –
>These are in shapes of porcelain jacket crown
>It is gold sub frame with porcelain jacket crowns
placed on it.
>Extremely good esthetics.
>Further more facing can be adapted easily.
>Gingivally placed solder joints are not good for
>Soldered junctions lead to weakness in porcelain
>There is gold tissue contact, not porcelain.www.indiandentalacademy.com
b) Posts :
>They are tube tooth, alumina tube pontic.
>Extremely strong oval alumina tube is positioned at
30 degree to occlusal plane.
>These tubes have 3.5-4.5 mm diameter with wall
thickness of 1 mm.
>This will allow for gold post of 1.5-2.5 mm which is
adequate if hard gold is used.
>On tube alumina core porcelain is fired which is built
upto 0.5 mm of final tooth contour and then veneer
porcelain is applied.
>Its main advantage is that it has all porcelain in tissue
4. Bonded pontics :
• Ideal combination is porcelain bonded to gold.
• Strength of gold is obtained with excellent esthetics
and tissue contact with porcelain.
• Advantage is pontic of different size and shapes can
• Only disadvantage is in lower anterior region where
limited space is available to accommodate both facing
5. Mechanical locking :
>Acrylic pontic is prepared and cured on gold work.
>Mechanical retention is obtained by surface
irregularities of gold.
>Whole of fit surface should be made of gold for
minimum gingival irritation.
Classification of pontics
• It is classified in 2 general groups :
1. Those that contact oral mucosa –
a) Ridge lap pontic
b) Modified ridge lap pontic
c) Ovate pontic
d) Conical pontic
2. Those that do not contact oral mucosa :
a) Sanitary pontic
b) Modified sanitary pontic
1. Sanitary or hygienic pontic :
• It is used in non appearance zone, mainly mandibular
• It restores occlusal function & stabilize opposing tooth.
• Occlusogingival thickness should not be less than 3
mm. and there should be adequate space to facilitate
• It is made in all convex configuration faciolingually and
• Undersurface of pontic is round without angles which
allows easy flossing. This design is called “Fish belly”.
• Its primary design feature is to allow easy cleaning.
• Its main disadvantage is food entrapment, that may
lead to tongue habit & this annoys patient.
2. Ridge lap or saddle pontic :
• It almost looks like a tooth, replacing all the contour of
a missing tooth, simulating the emergence profile of
missing tooth on both sides of ridge.
• It forms large concave contact with ridge, obliterating
the facial, lingual, & proximal embrasure.
• It is called ridge lap because it overlaps facial & lingual
surfaces of the ridge.
• It is impossible to clean and causes tissue
inflammation, so should not be used.
3. Modified ridge lap pontic :
• It combines the best features of hygiene & saddle
pontic design, combines esthetics with easy cleaning.
• This design overlaps the residual ridge on facial
surface but remains clear of the ridge on lingual
• Gingival surface should not have any depression or
hollow. It should be as convex as possible from mesial
to distal side for easier oral hygiene.
• The tissue contact should resemble letter “T” whose
vertical arm ends at crest of ridge.
• It is mostly used in maxillary & mandibular anterior
teeth maxillary premolars & 1st
4. Conical or bullet shaped or heart shaped pontic :
• It is recommended for mandibular posterior teeth
where esthetics is of lesser concern.
• Facial & lingual contours are dependent on width of
• It is made as convex as possible with only 1 point
contact at center of residual ridge.
• It is easy for patient to keep it clean.
• This design is unsuitable for broad residual ridge
because it may cause food entrapment ( sanitary
pontic is choice in this situation )
5. Ovate pontic :
• It was described by Dewey & Zugsmith in 1933.
• It is most esthetically appealing pontic design in use.
• Its convex tissue surface resides in a soft tissue
depression in residual ridge. It makes it appear that
tooth is emerging from gingiva.
• Careful treatment planning is required.
• Socket preservation technique should be performed at
the time of extraction to create tissue recess.
• Its broad convex geometry is stronger than modified
ridge lap pontic. Unsupported thin porcelain that exists
at gingivofacial extent of pontic is eliminated.
• It can be used in both anterior & posterior quadrants.
-Tooth fractured because of trauma, dental caries or
structural defects & has intact buccal plate.
-Medically compromised patients or unwilling patient for
• Contraindications :
-Facial or lingual or coronal or apical height is
inadequate to create bone & tissue contour necessary
to mimic dentogingival complex.
Ovate pontic formation procedure :
• Tooth preparation adjacent to extraction tooth is done.
• Impression with irreversible hydrocolloid is taken.
• Extract tooth, protect lateral papilla and buccal/ lingual
• Pour impression with die stone.
• Fit stent is made from stone model to verify stable fit.
• Use acrylic trimming bur to form pontic site in stone.
Coat stone preparation &ovate pontic site with
• Mix provisional material & pour into stent. Orient it
onto stone cast & place it in pressure pot.
• Trim the flash from provisional, adjust pontic for
correct depth & occlusion.
• Cement the provisional restoration with temporary
• Monitor it at monthly intervals, repolish the ovate
pontic at each visit.
• When healing is over then definitive prosthesis is
- It allows immediate replacement of a “ questionable”
tooth that is stable.
- Time is allowed for necessary healing to verify
esthetics, phonetics, & comfort factors.
- When a condemned tooth is removed carefully, it can
control tissue & bone contours.
- Ease of cleaning is better than other pontic with
proper formation of apex in provisional restoration.
• Patient may be reluctant to accept tooth preparation
lateral to lost tooth.
• Pontic formation is time consuming.
• Detailed attention to existing provisional restoration is
necessary for acceptable marginal fit.
• Final impression should be made immediately after
removal of provisional or tissue can rebound
1. Black triangles :
• They are very unaesthetic, collect plaque &
interferes with passage of floss.
• Pink porcelain is added to gingival embrasure area of
pontic to simulate interdental papilla, although the
exact shade rarely matches.
• Gingival extension of the porcelain must be supported
by metal framework.
2. Andrew’s bridge system :
a) Patients with excessive alveolar bone & tissue loss
but abutments are capable of supporting FPD.
b) Patients requiring diastemas to harmonize natural
c) When residual ridge has relationship to opposing
dentition that would prohibit esthetic placement of
• Appropriate bar is selected from preformed
curvatures available using diagnostic casts.
• Bar should follow the residual ridge & positioned at
center of replacement teeth.
• Tooth preparation is same but requires more reduction
of surface adjacent to edentulous space. It provides
adequate space for mechanical lock of bar in crown &
reduces distortion of margins during soldering.
• There should be sufficient clearance between bar &
tissue for oral hygiene.
• After abutment preparation cast is poured, wax
pattern is made, bar is positioned & casting is done.
• A sleeve is then placed over the bar, teeth are
positioned & flange completed in wax for try in.
• Lingual surface finished restoration can be made with
metal which is less bulky & stronger.
• Path of withdrawal of flange portion should be
divergent from the displacing forces exercised on fixed
1. More stable because it is totally tooth borne &
occlusal forces are directed more towards long axis
2. Pontic teeth are arranged during esthetic try in
3. Pontic assembly is removed for oral hygiene.
(The only disadvantage is failure of bar due to inadequate
3. Modified sanitary pontic or Perel pontic :
• It presents a free flowing archway in the region
adjacent to residual ridge.
• Makes food retention impossible.
• Makes easy for patient to remove debris.
• Prevents undue flexure of fixed prosthesis.
• Reshapes & reinforces the critical solder joint.
Gingival aspect –
• Concave mesiodistally.
• It gives additional room occlusogingivally to enhance
• Gingival aspect is slightly convex.
• It has rounded angles so no irritation to tongue.
• A high polish is mandatory.
Occlusal aspect –
• It is in harmony with adjacent & opposing tooth.
Proximal surface –
• Solder joints are elongated that increases the
• Each joints takes the form of normal buccal & lingual
sluiceways & an occlusal minor embrasure.
Occlusogingival depth –
• It should be thick enough to minimize the danger of
flexure, however at least occlusal third of
occlusogingival depth should be used.
• Amount of thickness will also depend on topography of
residual ridge & length of prosthesis.
4. Hygienic multiple pontic design : (Zuckerman)
• It is well suited for long span FPD because metal
casting is extremely rigid.
• Significance of this design is completely developed
labiogingival embrasure between adjacent pontics,
elimination of linguogingival embrasure adjacent
pontics & wide embrasure between pontic & retainers.
• This open embrasure facilitate oral hygiene.
• Pontics are formed with well rounded linguogingival
• Gingival facing surface make light contact with crest.
5. Modified ovate pontic : ( Steve )
• It overcomes the problems encountered with ovate
• It involves moving the height of contour at tissue
surface from the center of base a more labial position.
• It does not require much faciolingual thickness to
create emergence profile.
• It is easier to clean & major advantage is no need of
surgical ridge augmentation.
• Tissue surface is less convex than ovate pontic.
• It is indicated in anterior & posterior teeth with high
6. Arc-fixed partial denture design : (Tjan)
• It is designed for lower posterior arch. It is a modified
hygienic pontic & its connectors.
a) Buccal & lingual axial contour –
It retains 2/3rd
of occlusal portion of buccal surface &
half of occlusal portion of lingual surface to support
cheek & tongue. It is comfortable to patient.
• Undersurface should be slightly convex or flt
buccolingually to keep it clean.
• Junction between undersurface & buccal and ligual
surface must be round.
Occlusal surface –
• Buccolingual width of pontic should not be reduced to
maintain maxillary occlusal relationship with opposing
tooth & to protect tongue and cheek by providing
sufficient horizontal overlap.
c) Connector design –
• It should be 2 mm above residual alveolar ridge.
• The arcing undersurface, mesiodistally , will increase
the depth of connectors & will increase the strength of
7. Fused multiple pontic : (Behrend)
• In multiple pontics, ‘V’ shaped notches between
pontics on tissue surface causes plaque
• By fusing multiple pontics on tissue surface gives
smooth unbroken surface.
• Pink porcelain is used to fill interpontic embrasure.
• When anterior ridge is reduced then a layer of pink
porcelain is added over labial surface for esthetics.
8. Free end pontics : (Schweitzer)
• Restoration success depends on length, strength &
oval form of cuspid root, and labiolingual thickness of
• Lever arm is shortest & most favorable when lateral
incisor is supported by a cuspid or by a central incisor.
• When central incisor is supported by a central or
lateral incisor then lever arm is longest & least
9. Broken stress FPD :
• It is a type of free end pontic having only one soldered
or fixed end.
• Opposite end of pontic has a lug resting in a lug seat
in abutment tooth.
• It is used to replace single bicuspid where adjoining
teeth are strong & space is not large mainly in young
10. Hollow pontic design : (Shoher & Whitman)
• It has reinforced porcelain system that involves the
placement of concavities on the external surface of
• This design places the porcelain in compression
during firing cycle & results in great strength.
• It consists of hollow configuration with supporting belts
on buccal & lingual surfaces.
> Reduces casting weight by 40%.
> Reduces cost of metal.
> Decreased porosity from solidification shrinkage.
> Greater porcelain thickness to improve esthetics.
11. Scew connected FPD : (Gidden, Ecles & Day)
• It is used for tilted abutment tooth that cant be aligned
during tooth preparation.
• It has 2 parts which is attached by screw.
Clinical procedure :
• Prepare abutment tooth without attempting to make
• Make slicone impression & make provisional.
Lab procedure :
• Pour impression with stone with removable dies for
abutment & a further set of individual dies.
• Make transfer coping in cold cure acrylic on 2nd
die & fit accurately at margins.
Clinical procedure –
• Check fit of copings & it should be clear from opposite
• Record centric occlusion by addition of cold cure
Lab procedure –
• Mount maxillary & mandibular cast in centric
• Wax the restoration with a platform extending into the
edentulous space 1 mm clear of opposing occlusion.
• Sides of platform should taper occlusally.
• Mill 3 guiding grooves on 3 sides of platform parallel to
abutment tooth. It involves screw, collar & tube.
• Position the threaded tube at center of platform,
remove it & cast the retainer & platform and polish it.
• Reposition the tube in casting & solder into position
• Position the screw with collar into threaded tube so it
is clear of opposing tooth.
• Wax up other retainer & extend wax pattern to confirm
the platform & collar & head of screw. Invest & cast
incorporating the collar.
Clinical procedure –
• Check the fit, contour & occlusion. Seat the part with
platform first, when cement is still soft, place the screw
& tighten it.
12.Telescopic pontic :
• It is durable , color stable & eliminated the need for
processed acrylic or manufactured facing which are
difficult to obtain.
• By combining the dissimilar metals, it is possible to
take advantage of material properties of each.
• After tooth preparation, impression making, mounting
casts & sectioning of dies, anterior retainer is waxed &
• Before it is cast, 27 gauge gold zepher wire loop 3 is
attached to wax pattern.
• Posterior onlay & pontic substructure is then waxed &
cast as unit.
• Patient recalled to check fit & burnish the type 3 alloy
casting. Combination of resin & wax is used to make
pontic superstructure which is cast in Jelenko ‘O’ gold.
• Bibond porcelain is baked & glazed on this segment.
• No. 5 round bur hold provides adequate access for
soldering & produces rigid connector.
• This size opening is drilled through cast occlusal
surface of casting.
• Then flux & antiflux is applied, post soldering
procedure is carried out.
• Solder plug is made by heating the end of a piece of
solder in a Bunsen burner to allow a ball to form.
• The occlusal adjustments are completed after finishing
& FPD is cemented in place.
13. Natural tooth pontic : (Binkley, Noble, Wilson)
• Extracted natural tooth are used as pontic on acid
etched resin bonded metal FPD.
> Duplication of original tooth shade & morphology.
> Elimination of need of reglaze porcelain.
> Less complicated & less costly.
Non – Rigid Connectors :
• In some situations non-rigid connectors are used
either to relieve stress or to accommodate malaligned
Eg. – 1) Dove tails
2) Split pontics
3) Cross pins & wings
1) Dove tails :
• This technique is best suited for relieving stress at
midpoint on long axis.
• Align the path of insertion of keyway with that of distal
• Wax pattern is fabricated on cast for retainer on pier
• Deep box is carved into distal surface of wax pattern
to create space for placement of plastic keyway
• Surveying is done. Pattern is invested, burn out &
casting is done.
• Place casting on working cast & place prefabricated
plastic pattern for key into the keyway.
• Pontic wax pattern is attached with plastic key.
• Pontic wax pattern is completed, invested, burn out &
casting is done.
• Try in is done to verify the fit.
• Cement mesial unit first, then distal unit immediately.
2) Split pontic :
• It is an abutment that is placed entirely within the
• It is used in tilted abutment cases, where conventional
dove tail will cause preparation of very deep boxes in
distal part of pier abutment.
• Wax pattern of anterior 3 unit is fabricated first, with
distal arm attached to pier retainer.
• Underside of arm is shaped tissue contacting area of
• Surveyor is used ti position key & keyway.
• Invest, burn out & cast the mesial 3 & half unit
segment. Then seat it on working cast.
• Wax the distal retainer & disto occlusal 2/3rd
pattern. Casting is done.
• Try in & final adjustment is done.
• Cement the mesial segment first & then distal
segment with no cement between segments of pontic.
3) Cross pins & wings :
• Cross pins & wings are working segments of 2 piece
pontic system that allows the 2 segments to be rigidly
fixed after the retainers have been cemented.
• This design is mainly used in abutments with
desperate long axis.
• Attach a vertical wing to mesial surface of distal
retainer wax pattern. Wing should be parallel to path
• Extend it 3 mm mesially from distal retainer, have 1
mm thickness faciolingually & 1 mm short of occlusal
• Invest, burn out & cast the distal retainer with wing.
• Seat retainer on cast, drill 0.7 mm hole through wing.
• Place pencil lead through hole & build wax pattern
around lead & wing.
• Remove lead, withdraw the retainer pontic wax pattern
& fabricate the pin with same alloy.
• Cement the retainer with wing first followed by retainer
pontic system. Seat the pin in hole with punch &
• Remove excess of pin from buccal & lingual side.
Available pontic materials
1. Metal ceramic pontic :
It is strong, easy to keep clean & looks natural.
However mechanical failure occur if framework design
Principles of framework design –
a) It must provide uniform veneer of porcelain ( about
1.2 mm ).Excess of porcelain will cause inadequate
support & fractures.
b) Metal surface should be smooth & free of pits.
Surface irregularities cause incomplete wetting by
porcelain slurry, leading to voids.
c) Sharp angles at veneering areas should be rounded.
d) location of external metal-porcelain junction requires
attention, or will lead to chipping of porcelain. So
centric contacts should be 1.5 mm. away from
2. Resin veneered pontic :
a) Abrasive resistance is lower than enamel &
b) Dimensional change occur by water absorption &
c) No chemical bond at resin & metal framework.
d) Causes leakage at metal resin interface & discolors.www.indiandentalacademy.com
• Advantages :
a) Easy to manipulate & repair.
b) Do not require high melting range alloys.
3. Fiber reinforced composite resin pontics :
- It can be used without metal framework.
-Impregnated glass or polymer fibers provide structural
- It has excellent marginal adaptation & esthetics.
4. All acrylic pontics :
-It is used for fabrication of temporary bridge.
-It’s strength is less, low wear, low tissue tolerance, no
color stability, so it is unsatisfactory.
5. All porcelain pontic :
- It is only for all ceramic bridge.
- It gives excellent esthetics but it faces seldom
- It has all porcelain retainers in either side which is
more likely to fail.
6. All gold pontic :
- It is used in 2 instances ----
a) When there is limited space & esthetics is of little
b) Sanitary pontic- When esthetics is of less
importance & appreciable ridge resorption is present.
7. Castable glass ceramic pontic :
- It is used for partial veneer FPD, when a tooth
bounded edentulous areas require restoration.
Dicor – It is esthetic & durable dental material.
It is first cast as glass & then heat treated to
partially crystalline into a glass ceramic.
Composition is mainly Tetra silicic fluoromica
crystals which gives it strength.
• For a good pontic design, surface finish & ability to
maintain a hygienic state are more significant factors
affecting tissue response.
• Modification of edentulous ridge prior to pontic
placement must also be evaluated.
• Srapping the cast to attain better pontic contact
should be avoided. Positive contact without tissue
blanching is desirable.
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