Bridge and Pontic Design 2023,by dr. Mohammed Alqadasi. talking about the principles and considerations for proper bridge and pontic design , the pretreatment assessment and evaluation ,type of fixed partial denture and type of pontic , stage of design,and materials that used.

1. | ‫صفحة‬
1
Bridge and
Pontic Design
DONE BY
Dr. Mohammed Nabil Alqadasi
B.D.S Sana'a University
2023
SANA'A UNIVERSITY
FACUALITY OF
DENTISTRY

2. | ‫صفحة‬
2
PART ONE
Designing and
planning
bridges

3. | ‫صفحة‬
3
Introdaction
Fixed partial dentures (FPDs) are "dental prostheses that are luted, screwed, or
mechanically attached or otherwise securely retained to natural teeth, tooth
roots, and/or dental implant abutments.
"' During the past decades, many types of FPDs or "bridges" have been used to
replace missing teeth. With the introduction and widespread use of
osseointegrated implants, many missing teeth are now being replaced in this
manner rather than with FPDs. Dental bridges can, of course, still be used
successfully, and this article will briefly review the many methods of bridge
construction and relate them to their applicability and current acceptance of the
practicing dentist and the treated patient.
These will include: cast-gold, stress-broken bridges; resin-bonded, etched
retainers; porcelain-fused-to-metal (PFM) bridges; and all-ceramic bridges,
including zirconia.
Principles of design
In different areas of the mouth the relative importance of these will alter. The
principles guiding the
design of the bridge are:
• Cleansability
• Appearance
• support
• Conservation of tooth tissue
PRETREATMENT ASSESSMENT
1. Biomechanics :- Bending or deflection of prosthesis varies directly with the
cube of length and inversely with the cube of the occlusogingival thickness of
connector (Fig 5). Fig 5: Deflection of a fixed dental prosthesisunder load
To minimize flexing due to long span, pontic
designs with a greater occlusogingival dimension
should be selected and biomaterial with high
yield strength (eg.Nickel –chromium) is the
material of choice to fabricate to prosthesis .
2. Arch curvature :- Pontic acts as a lever arm
when it lies outside the interabutment axis line.
It can produce a torquing movement during
occlusion, which is most common in replacing maxillary four incisors. To offset

4. | ‫صفحة‬
4
the lever arm a counter balancing retention is provided by including 1st premolar
as secondary abutment
3. Abutment evaluation
a. Crown root ratio - Is the measurement of the length of tooth occlusal
to the alveolar crest of the bone compare with the length of root embedded in the
bone .The crown -root ratio is evaluated from radiological findings. The optimum
ratio is 2:3 whereas 1:1 can be accepted for further treatment. Antews low » The
root surface area (pericemental area )of the abutment teeth should be more or at
least equal to the rootsuface area (pericemental area )of the missing teeth being
replace.
b. Root configuration - Configuration of roots is also an important factor.
Roots with parallel sides and developmental depressions are better able to resist
heavy occlusal forces than smooth sided conical roots. Multirooted teeth
generally provide greater stability than single rooted teeth.
c. Periodontal ligament area - Periodontal ligament area is also called
root surface area or area of periodontal ligament attachment of the root to the
bone. In 1926 Irwin H Ante presented in his paper that - the total periodontal
membrane area of the abutment teeth must be equal or exceed that of the teeth
to be replaced. So root surface area is an important parameter when long span
FPD is considered (Fig 7A & B).
4. Span length :- Longer the span of a bridge the greater will be the stress
imposed on the abutment teeth and on all components of a bridge i.e. pontics,
retainer, connectors. To prevent periodontal overloading larger number of
abutment teeth has to be selected. The components of bridge must be enough to
bear heavy occlusal stress.
5. Occlusion and Biting force :- Treatment planning and prognosis of long span
FPD also depends on amount of biting force .Amount of biting force also
depends on whether it generated by natural dentition or any prosthesis, muscular
activity, parafunctional habits etc. Excessive occlusal forces can cause loosening
of the prosthesis through flexure or can cause fracture of ceramic components or
tooth mobility.

5. | ‫صفحة‬
5
6. Materials:- Components (connectors, retainers, pontics) of long span FPD
should
be fabricated of materials with high yield strength to prevent flexion (eg. Nickel –
Chromium).
7. Esthetics :– In most situations FPD provides the most esthetic means of
replacing missing teeth, provided no large defect in edentulous ridge is present
8. shape of ridge :- The contour of the saddle area will be taken into account in
determining whether a bridge with a movable buccal veneer or a partial denture
should be made, or whether
surgical ridge augmentation should be considered When a bridge is to be made,
the shape of the
ridge will affect the appearance of the pontic, and if this is likely to be a critical
factor, in other words if the neck of the pontic shows and the patient is very
concerned about their appearance, then one of the procedures described below
should be followed to ensure an acceptable final result.
9. Consideration of the whole patient:- With crowns, the choice may be
between crowning a tooth or extracting it, and the decision may well be to make
a crown even though many factors, for example, the patient’s age, attitude to
treatment or oral hygiene are less than ideal. With bridges, there is often the
alternative of a partial denture, a minimum-preparation bridge or a conventional
bridge or an implant, and so it may not be necessary to make so many
compromises. If there is any doubt, it is better to make a partial denture first.
THE BRIDGE CONSISTS OF:
1. Retainer: it is the part of the bridge which is cemented to the abutment teeth
.it could be full metal, full veneer with facing, partial veneer, post crown or inlay
etc
The main types:-
Major retainer: for a conventional posterior bridge should not be less than
an MOD inlay with full occlusal protection. For anterior teeth it is usually a
complete crown.
Minor retainer: do not need full occlusal protection may be a complete or
partial crown or a two- or three-surface inlay without full occlusion protection.
Minimum preparation where the occlusion is favorable.
2.Pontic: Is the part of the bridge which represent the missing tooth and it
connected to the retainer by a connector.

6. | ‫صفحة‬
6
3. connector: the part of the bridge which connect the pontic and the retainer, it
maybe rigid (solid joint) or movable joint (precision attachment, key and key way)
Types of connectors: Connectors are those parts of a fixed partial denture (FPD)
or splint that join the individual retainers and pontics together.
Usually this accomplished with rigid connectors, although nonrigid connectors
are used occasionally
The latter are usually indicated when it is impossible to prepare a common path
of insertion for the abutment preparations for an FPD.
The main types
a. Rigid:- cast connectors , soldered connectors, porcelain connectors
b. non rigid :- tenon mortise connectors ,loop connectors ,split pontic
connectors ,cross pin and wing connectors
4. abutment: Is the natural tooth which support the bridge and on which the
retainer 1s cemented (tooth or root)
Types of bridges
There are 4 main type of bridges
1. fixed _ fixed bridge
2. fixed movable bridge
3.cantilever bridge
4.resin bonded bridge (conservative bridge )
 Fixed _fixed bridge
In this type the pontic is attached to theretainers (mesial and distal)by rigid
connector(solid joint) so they should haveone path of insertion . This is the most
commonly used FPD
Advantages
1. maximum retention and support.
2. abutment teeth are splinted together.
3. the design is most practical for larger bridges .

7. | ‫صفحة‬
7
disadvantages
1.require preparation to be parallel
2. All the retainers are major retainers require extensive ,destructive preparation
of the abutment teeth.
3.Has to be cemented in one piece.
 Fixed movable bridge
In this type the pontic is attached toone distal major retainer(distal end of the pontic)
by fixed connector while the other end is attached to the minorretainer (in front of
pontic )by movable joint .it s indicated in case ofdrifted abutment teeth and difficulty
to obtaining parallel abutments.
Advantages:
1. preparations do not need to be parallel to each other.
2. more conservative of tooth tissue because preparations for minor
retainers are less destructive.
3. parts can be cemented separately .
Disadvantages
1.more complicated to constructin laboratory than fixed fixed bridge .
2. difficult to make temporary bridge .
 Fixed Movable partial Denture
It is defined as ,A fixed partial denture having one or more non rigid connectors ,
here a non rigid connector Is used to connect the components of the fixed partial
denture , commonly used non rigid connectors include Tenon Morti connector
(TMC), loop connector, split pontic connectors and cross pin and wing connectors
 Fixed Removable Partial dentures Removable Bridges
One of the major disadvantages of long span fixed partial denture is that If one
abutment fails, the entire prosthesis has to be sacrificed , to overcome this
disadvantage. Fixed removable bridges were introduce, these dentures cannot be
removed by the patient but can be easily removed by the dentist.

8. | ‫صفحة‬
8
 Modified Fixed Removable partial Dentures
They were developed by Andrew , hence they are also known as Andrew's bridge
systems. These denture are indicated for edentulous ridge with severe vertical
deficit, The prosthesis consists of a fixed component and a removable component
 Cantilever bridge
areas of your mouth that are under less stress, such as your front teeth, a cantilever
dental bridge may be used. A cantilever dental bridge is when the “false tooth” is
only supported on one side. The result is just as aesthetic but has the benefit that
fewer teeth have to be treated.
 Spring Cantilever
It is a tooth and tissue supported bridge. A pontic is supported at some distance
from the retainer . It is a type of cantilever bridge. Strong retention is required as for
all cantilever bridges and double abutments are usually necessary. The retention of
a spring bridge is severely tested when force is exerted in apicoincisal direction as
seen on biting sticky food as the retainer is subjected to detrimental stresses. To
avoid this, two retainers in adjacent teeth are used together to give added strength.
This bridge design is used while replacing anteriors with diastema or in case of
existing existiendodontically treated tooth posteriorly. This design cannot be used in
lower arch because of lack of suitable tissue support. The bar should follow the
natural contours of the rugae in the palate, so that it lies obscurely in the valleys and
its lateral margins do not represent an attraction to the tongue. The cross — section
of the bar should be a flat,oval or a rounded —T shape[8]. The model should be
lightly scraped to ensure firm seating on the soft tissue and minimize food trapping.
High platinized gold or spring metal is used. Class IV casting gold is ideal. The
Achilles heel with this design is the junction of retainerand the bar and the leverage
on the abutment.
 resin bonded bridge
A resin-bonded fixed partial denture is aprosthetic construction which can replace| or
several teeth in an occlusal system and which comprises a pontic element which is
adhesively attached to 1 or more abutment teeth. To compensate for the limited
shear strength of the adhesive layer, the Jixed partial denture is occlusally supported
by the abutment(s). A direct resin-bonded fixed partial denture is made of
composite, reinforcedor not by a frame of flexible metal or fiber material. For an
indirect resin- bonded fixed partial denture, a metal, fibre-reinforced composite or
ceramic substructure is fabricated in a dental laboratory. The basic principle of a
resin-bonded fixed partial denture is minimal invasiveness. However, a restoration in

9. | ‫صفحة‬
9
an abutment tooth requires a certain occlusal space which is realized by tooth
preparation. Resistance preparations may be performed to improve the longevity of
resin-bonded fixed partial dentures. Both financially and biologically, a resin-bonded
bridge is a cost-effective prosthetic construction. The longevity is limited, but when
the construction fails the negative consequences for the abutments are generally
limited, which leaves open several types of other treatments.
Resin retained bridges
1. Bonded pontic
2. Rochette bridge
3. Viginia bridge
4. Maryland bridge
5. Adhesive bridge
1. Bonded pontic
Introduced by Ibsen and Portnoy in 1973, these are the earliest resin retained
prosthesis[9]. They are the resin tooth or patient’s natural tooth bonded directly to
the etched enamel. These are meant for short term replacements. The limiting factor
was the weakness of the composite resin connector.
2.Rochette bridge
CAST PERFORATED RESIN-RETAINED FPDS (MECHANICAL RETENTIO In
1973, Rochette introduced the concept of bonding metal to teeth using flared
perforations of the metal casting to provide mechanical retention. He used the
technique principally for periodontal splinting but also included pontics in his design.
Howe and Denehy recognized the metal framework's improved retention (as
compared to bonded pontics) and began using FPDS with cast-perforated metal
retainers bonded to abutment teeth and metal-ceramic pontics to replace missing
anterior teeth. Their design recommendation, extending the framework to cover a
maximum area of the lingual surface,suggested little or no tooth preparation.Patient
selection limited these FPDs to mandibular teeth or situations with an open occlusal
relationship. The restorations were bonded with a heavily filled composite resin as a
luting medium. This concept was expanded toreplacement of posterior teeth by
Livaditis. Perforated retainers were used to increase resistance and retention. The
castings were extended interproximally into the edentulous areas and onto occlusal
surfaces. The design included a defined occlusogingival path of insertion by tooth

10. | ‫صفحة‬
10
modification, which involved lowering the proximal and lingual height of contour of
the enamel on the abutment teeth.
These restorations were placed in normal occlusion; many have survived and have
been seen on recall for up to 13 years Despite this success, the perforation
technique presents the following limitations: e Weakening of the metal retainer by
the perforation Exposure to wear of the resin at the perforations Limited adhesion of
the metal provided by the Perforations Clinical results with the perforated technique
were followed for 15 years in a study at the University of lowa.'-' The results from this
well-controlled study suggest that for anterior fixed partial dentures, 63% of the
perforated retainer prostheses fail in about 130 months.'6 Later data'-'indicate that
50% fail in about 110 mounths
3.MARYLAND BRIDGE
ETCHED CAST RESIN-RETAINED FPDS (MICROMECHANICAL RETENTION-
"MARYLAND BRIDGE")
Based on the work of Tanaka et al" on pitting corrosion for retaining acrylic resin
facings and the metal etching studies of Dunn and Reisbick," Thompson and
Livaditis at the University of Maryland developed a technique for the electrolytic
etching of Ni-Cr and Cr-Co alloys.
Etched castm retainers have definite advantages over the castperforated
restorations:
Retention is improved because the resin-toetched metal bond can be substantially
stronger than the resin-to-etched enamel. The retainers can be thinner and still resist
flexing. The oral surface of the cast retainers is highly polished and resists plaque
accumulation. During the course of this work, the need for a composite resin with a
low film thickness for luting the casting became apparent. This led to the first
generation of resin cements, which permitted micromechanical bonding into the
undercuts in the metal casting created by etching while providing adequate strength
and allowing complete seating of the cast retainers. Comspan,* the first of these
cements, was moderately filled (60% by weight) with a film thickness of
approximately 20 um.21 Such cements are not chemically adhesive to the
metal.Electrolytic etching of base metal alloys proved to be critically dependent on
the base metal alloy and attention to detail in the laboratory. Initial etching methods
were developed for a Ni-Cr alloy* and a Ni-Cr-Mo-Al-Be alloy. These methods were
followed by simplified techniques, chemical etching, 23 or attempts at gel etching. 24
They all yield similar results, provided the technique is optimized for a specific alloy.
Proper etching requires evaluation of the alloy surface with a scanning electron
microscope. The degree of undercut created by this etching process can be seen in

11. | ‫صفحة‬
11
Figure 26-3. Lack of attention to detail can result in electropolishing or surface
contamination .26 With time, both severely degrade bond strengths in a moist
environment. Highly variable results were reported for dental laboratories when
etching the same alloy . Etchingand bonding techniques were adopted based on
bond strength testing of specimens only subjected to 24 hours or 7 days of water
exposure. When resin-tometal test specimens were aged for 6 monthsin water and
then thermally stressed by 10,000 or more thermal cycles, large reductions in bond
strengths were recorded. Therefore, data from specimens that have not been aged
and thermally stressed should be viewed skeptically. Even particle abrasion will
provide initially high resin-to-metal bonds, which can degrade to almost zero with
time . Well-researched and tested resin systems for direct adhesion to metal
surfaces have now completely supplanted metal etching as retention mechanisms.
4.VIRGINIA BRIDGE
MACROSCOPIC MECHANICAL RETENTION RESINRETAINED FPDS ("VIRGINIA
BRIDGE")
As a result of concerns about etching base metal and the desire to use alternative
alloys, several methods have been developed to provide visible macroscopic
mechanical undercuts on the inner surface of FPD retainers. The first was
developed at the Virginia Commonwealth University School of Dentistry and is
known as the "Virginia Bridge. It involves a "lost salt crystal" technique. On the
working cast, the abutments are coated with a model spray, and a lubricant is then
applied. Within the outlines of the retainers, specially sized salt crystals* (150 to 250
um) are sprinkled over the surface in a uniform monolayer, leaving a 0.5-mm border
without crystals at the periphery of the pattern.
This is followed by application of a resin pattern. After pattern investment, the salt
crystals are dissolved from the surface of the pattern. Adequate bond strengths are
possible with this method, but the thickness of the casting must be increased to
allow for the undercut thickness.
Although no long- term results have been reported with this technique, it does
permit the use of almost any metal-ceramic alloy An alternative technique for
macroscopic retention is the use of a cast mesh pattern on the internal surface of the
retainers. The mesh, usually made of nylon,* should be adapted to the lingual and
proximal surfaces of the abutments. The mesh is then covered by wax or resin; this
must be done carefully to prevent occluding the mesh with the pattern material.
Investing and casting then followThis method is technique sensitive but can provide
adequate retention with a resulting thick lingual casting. The cast mesh and the lost

12. | ‫صفحة‬
12
salt crystal method have been supplanted by direct adhesion with resin, which is
possible for most casting alloys if the correct surface treatment is provided
5. Adhesive Bridges
Inspite of electrochemical etching being very popular in America, alloy etching and
macroscopic retention is obsolete in Japan since 1980s . As a result of extensive
research chemically active adhesive cements were developed for direct bonding to
metal . These cements rely on chemical adhesion to the metal and not on
microretention in the surface of the metal for bond strength. Etching was no longer
necessary[ 19] Adhesive bridge shows chemical bonding between the metal and the
resin luting agent. Direct bonding involves the chair side and lab systems.
Metabond is first of these resin systems. It 1s based on formulation of Methylmetha
acrylate (MMA) polymer powder and MMA liquid modified with adhesion promoter 4
META (4-methacryloxyethyl trimellitate anhydride). Unique tributyl borane catalyst
1s added to liquid. On base metal alloys, Superbond has highest initial bond
strengths of any adhesive resin systems[20]. But, it gives weak bond with high gold
alloys and the bond shows hydrolytic instability. Introduction of Metabond was
followed by Panavia which can be used both with high gold ( after tin plating) and
base metal alloy. Tin plating can be done in lab, chair side or intraorally. Intraoral tin
plating 1s done by tin amide solution. Adhesive monomer used in Panavia 1s
MDP(10- methacrylolyloxydecyl dihydrogen phosphate). The phosphate end reacts
with Calcium of tooth and with the metal oxide. Bond strength to etched base metal
is greatly exceeded to that of tooth. Lab system for adhesive bonding have been
developed. Silicoater Classical ( Tiller et. al , 1984) 1s based on the need for an
intermediate layer containing silica as this provides sufficient bonding of the resin via
a silane bonding agent. New version of Silicoater MD was introduced in 1998.This
uses a special oven that burns a chrome endowing silica layer onto the surface.
Pyrosil Pen Technology (1998) is the chairside version of silicoater. Rocatec
System is a novel acrylic and metal bonding system which uses a tribochemical and
thermal embedding of a silica layer by means of sand blasting on the metal
surface[22]. Metal is thus rendered more reactive to resin via silane. [t is unfortunate
that this treatment modality 1s not very popular amongst dentist but if the case
selection 1s proper it offers outstanding conservatism with tremendous bond
strength.

13. | ‫صفحة‬
13
stages in the design process
 Selecting abutment teeth
After the general examination of the patient and whole mouth, individual potential
abutment teeth should be examined and a note made of the presence of caries or
restorations and the extent
and quality of any restoration present. The periodontal state should be examined,
including the presence of plaque and other deposits, gingival bleeding and
periodontal pockets. The vitality and mobility of the tooth should be tested and a
periapical radiograph obtained. Usually any major problems with the individual tooth
should be dealt with first by appropriate treatment, but sometimes the more sensible
solution is to extract the tooth and replace it as an additional pontic on the bridge
rather than retain a dubious tooth as an abutment when its presence may well
jeopardize the future of the whole bridge. An example of this is where three lower
incisor teeth are already missing and the
fourth has very little bone support. The lower canines are sound and will make good
abutment teeth. They will have to be used in any case to support the bridge.
Including the remaining incisor will not add significantly to the support of the bridge
and may well detract from its long term prognosis.
A judgement must be made as to the prognosis of all the teeth in the vicinity of the
bridge and in the rest of the mouth to reduce the risk of another tooth having to be
extracted shortly after the bridge is made.
 Selecting the retainers
The list of potential alternative retainers will include minimum-preparation, complete
and partial crowns retainers. The choice of a crown is inevitable when the tooth is
already heavily restored. The choice between a minimum-preparation retainer and a
crown will depend upon whether the abutment teeth have restorations in them, the
occlusal clearance and the appearance of the abutment teeth. If the only difficulty
with minimum-preparation retainers is the lack of occlusal clearance.
 Selecting the pontics and connectors
The design of pontics and connectors is the responsibility of the dentist and not the
technician.
Detailed instructions should be given to the technician, particularly on the contour of
the

14. | ‫صفحة‬
14
ridge surface of the pontic . When the technician is unfamiliar with the dentist’s usual
requirements, the details of the design should be drawn and sent to the technician
as part of
the prescription for the bridge. Where a metal–ceramic pontic is to be made, the
dentist should indicate where the porcelain should be finished. In some cases an all-
porcelain occlusal surface is required; in others the porcelain covers only the buccal
surface and buccal cusp, leaving the remainder of the occlusal surface in metal.
Again, this should be specified.
 Planning the occlusion
The first decision to be made is whether to articulate study casts and, if so, whether
it is necessary to use a simple hinge or semi-adjustable articulator. With small
bridges it is helpful to mount casts on at least a simple hinge articulator. With most
large bridges a semi-adjustable or fully adjustable articulator should be used. The
second decision is whether any occlusal adjustment is necessary prior to tooth
preparations for the bridge. With posterior bridgework it is often necessary to adjust
an over-erupted opposing tooth The anticipated occlusal relationship of the pontic
with the opposing teeth may influence the basic design of the bridge as well as the
details of the occlusal surface of the pontic; although this step is listed as the final
one in the sequence, and it is usually considered last. If the bridge design is
influenced by it, it will be necessary to introduce feedback loops to earlier stages

15. | ‫صفحة‬
15
PART TWO
Pontic
Design

16. | ‫صفحة‬
16
Introdaction
Pontics are the artificial teeth of a partial fixed dental prosthesis (FDP) that
replace missing natural teeth, restoring function and appearance. They must
enable continued oral health and comfort. The edentulous areas where a fixed
prosthesis is to be provided maybe overlooked during the treatment-planning
phase. Unfortunately, any deficiency or potential problem that may arise during
the fabrication of a pontic is often identified only after the teeth have been
prepared or even when the definitive cast is ready to be sent to the laboratory.
Proper preparation includes a careful analysis of the definitive dimensions of the
edentulous areas: mesiodistal width, occlusocervical distance, buccolingual
dimension, and location of the residual ridge. To design a pontic that meets
hygienic requirements and prevents irritation of the residual ridge, particular
attention must be given to the form and shape of the gingival surface. Merely
replicating the form of the missing tooth or teeth is not enough. The pontic must
be carefully designed and fabricated not only to facilitate plaque control of the
tissue surface and around the adjacent abutment teeth but also to adjust to the
existing occlusal conditions. In addition to these biologic considerations, pontic
design must incorporate mechanical principles for strength and longevity, as well
as esthetic principles for satisfactory appearance of the replacement teeth
Because the pontic mechanically unifies the abutment teeth and covers a portion
of the residual ridge, it assumes a dynamic role as a component of the prosthesis
and cannot be considered a lifeless insert of gold, porcelain,
or acrylic resin.
Principles of design
Pontics are designed to serve the three main functions of a bridge:
• To restore the appearance
• To stabilize the occlusion
• To improve masticatory function.
In different areas of the mouth the relative importance of these will alter. The
principles guiding the
design of the pontic are:
• Cleansability
• Appearance
• Strength.
1. Cleansability
All surfaces of the pontic, especially the surface adjacent to the saddle, should be
made as cleansable as possible. This means that they must be smooth and
highly polished or glazed, and should not contain any junctions between different
materials. In a metal–ceramic pontic the junction between the two materials
should be well away from the ridge surface of the pontic.

17. | ‫صفحة‬
17
It is important too that the embrasure spaces and connectors should be smooth
and cleansable.
They should also be as easy to clean as possible. Access to them and the
patient’s dexterity should be taken into account in designing pontics. When a
conflict exists between cleansability
and appearance, priority should be given to cleansability.
2. Appearance
Where the full length of the pontic is visible, it must look as tooth-like as possible.
However, in
the premolar and first molar region it is often possible to strike a happy
compromise between a reasonable appearance for those parts of the pontic that
are visible and good access for cleaning
towards the ridge.
3. Strength
All pontics should be designed to withstand occlusal forces, but porcelain pontics
in the anterior part of the mouth may not of course be expected to withstand
accidental traumatic
forces. The longer the span, the greater the occlusal gingival thickness of the
pontic should be.
Metal–ceramic pontics are stiffer and withstand occlusal forces better if they are
made fairly thick
and if the porcelain is carried right round them from the occlusal to the ridge
surface, leaving only a line of metal visible on the lingual surface or none at all
In other word three important consideration:-
BIOLOGIC CONSIDERATIONS
The biologic principles of pontic design
pertain to the maintenance and
preservation of the residual ridge,
abutment and opposing teeth, and
supporting tissues. Factors of specific
influence are pontic-ridge contact,
amenability to oral hygiene, and the
direction of occlusal forces.
 Ridge Contact
Pressure-free contact between the
pontic and the underlying tissues
prevents ulceration and inflammation
of the soft tissues.If any blanching of
the soft tissues is observed at
evaluation, the pressure area should
be identified with a disclosing medium
(e.g., pressure-indicating paste), and

18. | ‫صفحة‬
18
the pontic should be recontoured until tissue contact is entirely passive. This
passive contact should occur exclusively on keratinized attached tissue. When a
pontic rests on mucosa, some ulceration may appear as aresult of the normal
movement of the mucosa in contact with the pontic . Positive ridge pressure
(hyperpressure) may be caused by excessive scraping of the ridge area on the
definitive cast. This was once promoted as a way to improve the appearance of
the pontic-ridge relationship. However, because of the ulceration that inevitably
results when flossing is not meticulously performed, the concept is not
recommended unless followed as previously described for an ovate pontic.
Although ovate pontics maintain positive
tissue contact to support the pseudopapillae, healthy mucosa can be maintained
if the contact to the mucosa is tight but noncompressive and the gingival portion
of the pontic is regularly cleaned
ESTHETIC CONSIDERATIONS
No matter how well biologic and mechanical principles have been followed during
fabrication, the patient evaluates the result by how it looks, especially when anterior
teeth have been replaced. Many esthetic considerations that pertain to single crowns
also apply to pontics. Several problems unique to pontics may be encountered in the
attempt to achieve a natural appearance.
 Incisogingival Length
Correctly sizing a pontic simply by duplicating the original tooth is not possible. Ridge
resorption makes such a pontic look too long in the cervical region. The height of a tooth
is immediately obvious when the patient smiles and shows the gingival margin (Fig. 20-
37). An abnormal labiolingual position or cervical contour, however, is not immediately
obvious. This fact can be used to produce a pontic of good appearance by recontouring
the gingival half of the labial surface (see Fig. 20-36). The observer sees a normal tooth
length but is unaware of the abnormal labial contour. The illusion is successful.
Even 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 (Fig. 20-38). Another approach is to use pink
porcelain to simulate the gingival tissues (Fig. 20-39). However, such pontics then have
considerably increased tissue contact and require scrupulous plaque control for long-
term success. Ridge augmentation procedures have been successful in correcting areas
of limited resorption. When bone loss is severe, the esthetic result obtained with a partial
removable dental prosthesis is often better than that obtained with an FDP

19. | ‫صفحة‬
19

20. | ‫صفحة‬
20
 Mesiodistal Width
Frequently, the space available for a pontic is greater or smaller than the width of the
contralateral tooth. This is usually because of uncontrolled tooth movement that
occurred when a tooth was removed and not replaced. If possible, such a discrepancy
should be corrected by orthodontic treatment. If this is not possible, an acceptable
appearance may be obtained by incorporating visual perception principles into the pontic
design. In the same way that the brain can be confused into misinterpreting the relative
sizes of shapes or lines because of an erroneous interpretation of perspective, a pontic
of abnormal size may be designed to give the illusion of being a more natural size. The
width of an anterior tooth is usually identified by the relative positions of the mesiofacial
and distofacial line angles, and the overall shape by the detailed pattern of surface
contour and light reflection between these line angles. The features of the contralateral
tooth (Fig. 20-41) should be duplicated as precisely as possible in the pontic, and the
space shape of the proximal areas. The retainers and the pontics can be proportioned to
minimize the discrepancy. (This is another situation in which a diagnostic waxing
procedure helps solve a challenging restorative problem.) Space discrepancy presents
less of a problem when posterior teeth are being replaced (Fig. 20-42) because their
distal halves are not normally visible from the front. A discrepancy here can be managed
by duplicating the visible mesial half of the tooth and adjusting the size of the distal half.

21. | ‫صفحة‬
21
 The Gingival Interface
An esthetically successful pontic replicates the form, contours, incisal edge,
gingival and incisal embrasures, and color of adjacent teeth. The pontic’s
simulation of a natural tooth is most often betrayed at the tissue-pontic junction.
The greatest challenge in this situation is to compensate for anatomic changes
that occur after extraction. To achieve a “natural” appearance, special attention
should be paid to the contour of the labial surface as it approaches the tissue-
pontic junction. This cannot be accomplished by merely duplication of the facial
contour of the missing tooth; after a tooth is removed, the alveolar bone

22. | ‫صفحة‬
22
undergoes resorption or remodeling, or both. If the original tooth contour were
followed, the pontic would look unnaturally long incisogingivally . For an esthetic
pontic to achieve the illusion of a natural tooth, observers must think that they are
seeing a natural tooth. The modified ridge-lap pontic is recommended for
most anterior situations; it compensates for lost buccolingual width in the residual
ridge by overlapping what remains. Rather than emerging from the crest of the
ridge as a natural tooth would, the cervical aspect of the pontic sits in front of the
ridge, covering any abnormal ridge structure that results from tooth loss.
Fortunately, because most teeth are viewed from only two dimensions, this
relationship remains undetected. A properly designed, modified ridge-lap pontic
provides the required convexity on the tissue side, with smooth and open
embrasures on the lingual side for ease of cleaning. This is difficult to
accomplish. Clinically, many pontics have suboptimal contour, which results in an
unnatural appearance. This can be avoided with careful preparation at the
diagnostic waxing stage . Sometimes the ridge tissue must be surgically
reshaped to enhance the result. In normal situations, light falls from above, and
an object’s shadow is below it. Unexpected lighting or unexpectedly positioned
shadows 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. The dentist must carefully study
where shadows fall around natural teeth, particularly around the gingival margin.
If a pontic is poorly adapted to the residual ridge, there is an unnatural shadow in
the cervical area that looks odd and spoils the illusion of a natural tooth. In
addition, recesses at the pontic-gingival interface collect food debris, further
ruining the illusion of a natural tooth. When appearance is of utmost concern, the
ovate pontic, used in conjunction with alveolar preservation or soft tissue ridge
augmentation, can provide an appearance at the gingival interface that is virtually
indistinguishable from that of a natural tooth. Because it emerges from a soft
tissue recess, this pontic is not susceptible to many of the esthetic pitfalls
applicable to the modified ridge-lap pontic. However, in most circumstances,
the patient must be willing to undergo the additional surgical procedures that are
necessary for placement of an ovate pontic
.
MECHANICAL CONSIDERATIONS
The prognosis of FDP pontics is compromised if mechanical principles are not followed
closely. Mechanical problems may be caused by improper choice of materials, poor
framework design, poor tooth preparation, or poor occlusion. These factors can lead to
fracture of the prosthesis or displacement of the retainers. Long-span posterior FDPs are
particularly susceptible to mechanical problems. Inevitably, significant flexing occurs as a
result of 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, rather than a metal-
ceramic pontic, may be needed in high-stress situations, in which it would be more
susceptible to fracture. When metal-ceramic pontics are chosen, extending porcelain

23. | ‫صفحة‬
23
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.
PRETREATMENT ASSESSMENT
Certain procedures enhance the success of an FDP. In the treatment-planning
phase, diagnostic casts and waxing procedures may prove especially valuable for
determining optimal pontic design:-
Pontic Space
One function of an FDP is to prevent tilting or drifting of the adjacent teeth into
the edentulous space. If such movement has already occurred, the space
available for the pontic may be reduced and its fabrication complicated.
In such circumstances, creating an acceptable appearance without orthodontic
repositioning of the abutment teeth is often impossible, particularly if esthetic
appearance is important. (Modification of abutments with complete-coverage
retainers is sometimes feasible.) Careful diagnostic waxing procedures help
determine the most appropriate treatment. Even with a lesser esthetic
requirement, as for posterior teeth, overly small pontics are unacceptable
because they trap food and are difficult to clean. When orthodontic repositioning
is not possible, increasing the proximal contours of adjacent teeth may be better
than making an FDP with undersized pontics. If there is no functional or esthetic
deficit, the space can be maintained without prosthodontic intervention.
Residual Ridge Contour
The edentulous ridge’s contour and topography should be carefully evaluated
during the treatment-planning phase. An ideally shaped ridge has a smooth,
regular surface of attached gingiva, which facilitates maintenance of a plaque-
free environment. Its height and width should allow placement of a pontic that
appears to emerge from the ridge and mimics the appearance of the neighboring
teeth. Facially, it must be free of frenum attachment and be of adequate facial
height to sustain the appearance of interdental papillae.
Siebert classified residual ridge deformities into three categories:-
• Class I defects: faciolingual loss of tissue width with normal ridge height
• Class II defects: loss of ridge height with normal ridge width
• Class III defects: a combination of loss in both dimensions
Loss of residual ridge contour may lead to unaesthetic open gingival embrasures
food impaction and percolation of saliva during speech.
Surgical Modification
Although residual ridge width may be augmented with hard tissue grafts, this is
usually not indicated unless the edentulous site is to receive an implant

24. | ‫صفحة‬
24
Gingival Architecture Preservation
By conditioning the extraction site and providing a matrix for healing, the dentist
can preserve the preextraction gingival architecture, or “socket.” Preparing the
abutment teeth before the extraction is the preferred technique. An interim FDP
can be fabricated indirectly, ready for immediate insertion. Because socket
preservation is dependent on underlying bone contour, the extraction of the tooth
to be replaced should be atraumatic, with the aim of preserving the facial plate
of bone. The scalloped architecture of interproximal bone forming the extraction
site is essential for proper papilla form, as are facial bone levels in the prevention
of alveolar collapse. If bone levels are compromised before or during extraction,
the sockets can be grafted with an allograft material (hydroxyapatite, tricalcium
phosphate, or freeze-dried bone).
The surfaces of a pontic
A pontic has five surfaces:
• The ridge
• The occlusal
• The approximal
• The buccal or labial
• The lingual or palatal.
Some of these will be similar to the natural tooth
being replaced; others will be very different.
The ridge surface
This surface of the pontic is the most difficult to
clean, and yet it also has a considerable influence
on appearance. The basic designs of
ridge surface (box 20-1).
1. Sanitary or Hygienic Pontic
As its name implies, the primary design feature of the sanitary pontic allows easy
cleaning because its tissue surface remains clear of the residual ridge (Fig. 20-
13, A). This hygienic design enables easier plaque control by allowing gauze
strips and other cleaning devices to be passed under the pontic and seesawed in
a shoeshine manner. Disadvantages include entrapment of food particles, which
may lead to tongue habits that annoy the patient. The hygienic pontic is the least
tooth like design and is therefore reserved for teeth seldom displayed during
function (i.e., the mandibular molars). A modified version of the sanitary pontic
has been developed (see Fig. 20-13, B and C). Its gingival portion is shaped like
an archway between the retainers. This geometry allows for increased connector
size and a decrease in the stress concentrated in the pontic and connectors.It is
also less susceptible to tissue proliferation that can occur when a pontic is too
close to the residual ridge (see Fig. 20-13, D).

25. | ‫صفحة‬
25
2. Saddle and Ridge-Lap Pontics
The saddle pontic has a concave fitting surface that overlaps the residual ridge
buccolingually, simulating the contours and emergence profile of the missing
tooth on both sides of the residual ridge. However, saddle or ridge-lap designs
should be avoided because the concave gingival surface of the pontic is not
accessible to cleaning with dental floss, which leads to plaque accumulation. This
design deficiency has been shown to result in tissue inflammation.
(a) A classic saddle or ridge lap pontic.
(b) A linguogingival ridge
(arrow) or extension past the crest of
the ridge, although less severe, still
constitutes a saddle
3. Modified Ridge-Lap Pontic
The modified ridge-lap pontic combines the best features of the hygienic and
saddle pontic designs, combining esthetics with easy cleaning. demonstrate how
the modified ridge-lap pontic overlaps the residual ridge on the facial side (to
achieve the appearance of a tooth emerging from the gingiva) but remains
clear of the ridge on the lingual side. To enable optimal plaque control, the
gingival surface must have no depression or hollow; rather, it should be as
convex as possible from mesial to distal aspects (the greater the convexity,
the easier the oral hygiene). Tissue contact should resemble a letter T whose
vertical arm ends at the crest of the ridge. Facial ridge adaptation is essential for

26. | ‫صفحة‬
26
a natural appearance. Although this design was historically referred to as ridge-
lap design, the term ridgelap is now used synonymously with saddle design The
modified ridge-lap design is the most common pontic form used in areas of the
mouth that are visible during function (maxillary and mandibular anterior teeth
and maxillary premolars and first molars).
4. Conical Pontic
Often called egg-shaped, bullet-shaped, or heart-shaped, the conical pontic is
easy for the patient to keep clean. It should be made as convex as possible and
should have only one point of contact: at the center of the residual ridge. This
design is recommended for the replacement of mandibular posterior teeth, for
which esthetic appearance is a lesser concern. The facial and lingual contours
are dependent on the width of the residual ridge; a knife-edged residual ridge
necessitates flatter contours with a narrow tissue contact area. This type of
design may be unsuitable for broad residual ridges because the emergence
profile associated with the small tissue contact point may create areas of food
entrapment . The sanitary or hygienic pontic is the design of choice in these
clinical situations.
Conical pontic used correctly with a thin
ridge (a) and incorrectly with a broad,
flat ridge (b). The arrows indicate
debris-trapping embrasure spaces.
5. Ovate pontic
The ovate pontic is a round-end design currently in use where esthetics is a
primary concern. Its antecedent was the porcelain root-tipped pontic, which was
used considerably before 1930 as an esthetic and sanitary substitute for the
saddle pontic. The tissue-contacting segment of the ovate pontic is bluntly
rounded, and it is set into a concavity in the ridge. It is easily flossed. The

27. | ‫صفحة‬
27
concavity can be created by placement of a provisional fixed partial denture with
the pontic extending one-quarter of the way into the socket immediately after
extraction of the tooth. It also can be created surgically at some later time. This
pontic works well with a broad, flat ridge, giving the appearance that it is growing
from the ridge.
The round-end ovate pontic fits into a
depression in the ridge.
The occlusal surface
The occlusal surface of the pontic should resemble the occlusal surface of the
tooth it replaces. Otherwise it will not serve the same occlusal functions and may
not provide sufficient contacts to stabilize the occlusal relationships of its
opponents. In some cases, when occlusal stability is less important (for example
when the pontic is opposed by another bridge), the pontic may be made narrower
bucco-lingually to improve access for cleaning. Other arguments for narrowing
pontics are less convincing .
 Occlusal Forces
Reducing the 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, although it has little scientific
basis. Critical analysis has revealed that forces are lessened only when food of
uniform consistency is chewed and that a mere 12% increase in chewing
efficiency can be expected from a one-third reduction of pontic width. Potentially

28. | ‫صفحة‬
28
harmful forces are more likely to be encountered if an FDP is loaded by the
accidental biting on a hard object or by parafunctional activities such as bruxism,
rather than by chewing of foods of uniform consistency. Narrowing the occlusal
surface does not reduce these forces. In fact, narrowing the occlusal surface may
actually impede or even preclude the development of a harmonious and stable
occlusal relationship. Like a malposed tooth, it may cause difficulties in plaque
control and may not provide proper cheek support. For these reasons, pontics
with normal occlusal widths (at least in the occlusal third) are generally
recommended. One exception is the situation in which the residual alveolar ridge
has collapsed buccolingually. Reducing pontic width may then be desired and
would thereby lessen the lingual contour and facilitate plaque-control measures.
The approximal surfaces
The shape of the mesial and distal surfaces of the pontic will depend upon the
design. With fixed–fixed bridges the approximal surface will consist partly of a
fixed connector. It is important that the embrasure space between the connector
and the gingival tissue be as open as possible to ensure that there is good
access for cleaning, particularly if the pontic is a ridge-lap or saddle pontic
(Figure 9.7). The gingival side of a movable joint is more difficult to leave entirely
smooth, and so it is again important that there should be good access for
cleaning. A balance has to be achieved to ensure that there is adequate
metal present to provide sufficient strength and rigidity for the connector as well
as allowing open embrasures for cleaning. The approximal surface of a cantilever
bridge on its free side will simply make normal contact with the adjacent tooth, or
in some cases there may be a diastema with no contact. Occasionally, where the
span is very short, a cantilever pontic may be made to overlap the adjacent tooth
to improve its appearance. In this case the pontic surface in contact with the
natural tooth should be as smooth as possible, although it may be slightly
concave. If the patient is taught to clean with dental floss, the natural tooth
surface should not be any more susceptible to caries than with a normal contact
point.
Figure 9.7 Well-contoured open embrasure spaces.

29. | ‫صفحة‬
29
The buccal and lingual surfaces
The buccal surface of a wash-through or domeshaped pontic does not resemble
the shape of a natural buccal surface, particularly gingivally. With ridge-lap and
saddle pontics the buccal surface is intended to look as much like a tooth as
possible for its entire length. The problem is that when a tooth is missing, so also
is some of the alveolar bone that supported it. This means that the alveolar
contour where the pontic touches the ridge never looks entirely natural, and the
pontic must also be shaped unnaturally to meet the resorbed ridge. The
aesthetic result is not good and there is greater difficulty than necessary in
cleaning. No ridge–pontic relationship can ever appear entirely natural, even
when the ridge has not resorbed significantly or where it has been augmented –
see Figure 7.9. But at the normal distance from which teeth are seen, the illusion
that the tooth emerges from the gum can be sufficiently convincing. The lingual
surface of a pontic will be designed as a result of deciding the ridge surface. With
ridge-lap pontics, the lingual surface should be smooth and convex.
Post-insertion Hygiene
The mesial, distal, and lingual gingival embrasures of the pontic should be
wide open to allow the patient easy access for cleaning, and the contact between
pontic and tissue must allow the passage of floss from one retainer to the other.
After the fixed partial denture is cemented, the patient should be taught
appropriate technique(s) that can be mastered. The individual should be
motivated to practice good hygiene around and under the pontic with dental floss,
interproximal brushes, or pipe cleaners. The method used will depend on
embrasure size, accessibility, and patient skill. The patient should be given time
to learn the techniques and demonstrate the ability to clean the underside of the
pontic and the adjacent areas of the abutment teeth. Home care is evaluated at
each appointment, and the necessity for good hygiene and the skills to
accomplish it are reinforced. Even the smoothest pontic surface must be cleaned
well and often to prevent the accumulation of plaque. If cleaning is not done at
frequent, regular intervals, the tissue around the pontic will become inflamed.

30. | ‫صفحة‬
30
Pontic Materials
Some FDPs are fabricated entirely of metal, porcelain, metal-ceramic, or acrylic
resin, but most consist of a combination of metal and porcelain. The acceptance
of acrylic resin–veneered pontics has been limited because of their reduced
durability (wear and discoloration). The newer indirect composites, which are
based on high inorganic content–filled resins and fiber-reinforced materials, have
revived interest in composite resin and resinveneered pontics.
Fiber-Reinforced Composite Resin
Pontics Composite resins can be used in partial FDPs without a metal
substructure. A substructure matrix of impregnated glass or polymer fiber
provides structural strength. Because of the physical properties of this system,
combined with its excellent marginal adaptation and esthetics, it is a possible
metal-free alternative for FDPs, although long-term clinical performance is not yet
known
Prefabricated pontic facings
Historically, preformed porcelain facings were popular for fabricating pontics.
They required adaptation to a specific edentulous space, after which they were
reglazed. Some, such as Trupontics, Sanitary Pontics, and Steele’s Facings
(Franklin Dental), relied on a lug in a custom cast metal backing to engage a slot
contraindication
Indication
Disadvantges
Advantages
Materail
Long spans with
high stress
Most
situations
Difficult to fabricate if
an an abutment is not
metal ceramic
Weaker than all metal
Nonesthetic
Esthetics
Biocompatible
Metal
ceramic
Where esthetics
is imprtomant
Mandibular
molars,
especially
under high
occlusal force
Nonesthetic
Strength
Straightforward
Procedure
All metal
Long span with
high stress
High esthetic
demand
Risk of fracture
Unable to sectioned
and reconnected
Large connectors
needed
Best esthetics
Biocompatible
All ceramic
Definitive
restorations
Long term
provisional
Poor abrasion
resistance
Staining at resin metal
interface
Permeable to oral
fluids
Straightforward
procedure
Resin
veneered

31. | ‫صفحة‬
31
in the occlusal or lingual surface of the facing. The large bulk of porcelain could
result in a thin gold backing susceptible to flexing. Harmony (Harmony Dental)
and Trubyte (Dentsply) facings used horizontal pins that fit into the gold backing.
They were difficult to use in patients with limited occluso-gingival space, and
refitting the pins into a backing after casting was demanding. Porcelain denture
teeth also were modified to use as pontic facings. Multiple pinholes 2.0 mm deep
were made with a drill press in the lingual surface of the reverse pin facing. The
pins protruded from the backing, providing retention where a deep overbite would
have over shortened conventional pins. Unfortunately, the pinholes in the facing
were stress points that led to fracture.

32. | ‫صفحة‬
32
Reference
 Planning and making crowns and bridges Fourth Edition(2007)
Bernard G N Smith & Leslie C Howe.
 CONTEMPORARY FIXED PROSTHODONTICS FIFTH
EDITION(2016) Stephen F. Rosenstiel , Martin F. Land, and Junhei
Fujimoto.
 Fundamentals of Fixed Prosthodontics, 4ed (2012) , Herbert T.
Shillingburg, Jr, DDS et al .
 Long Span Fixed Partial Denture - A Review Article , Asish Kumar
Barui et al , Maven 2019, www.idahowrah.org.