Retainers in FPD (FIXED PARTIAL DENTURES) PDF copy

RETAINERS IN FPD
NAMITHA.AP
2ND MDS
DEPT.OF PROSTHODONTICS

CONTENTS
 INTRODUCTION
 CLASSIFICATION OF RETAINERS
 REQUIREMENTS
 FACTORS AFFECTING SELECTION OF RETAINERS
 EXTRACORONAL RETAINERS
FULL VENEER CROWNS
PARTIAL VENEER CROWN RETAINERS
RESIN BONDED RETAINERS
 INTRACORONAL RETAINERS
 RADICULAR RETAINERS
 CONCLUSION
 REFERENCES

Introduction
unites the abutment(s ) to the remainder of the restoration
Nallaswamy D. Textbook of prosthodontics. JP Medical Ltd; 2017 Sep 30.642
Retainer is a crown or
any restoration that is
cemented
to the abutment
medium
through which
mechanical
and physical
forces are
translated into
physiological
functions and
biological
reactions in
living tissues.
Tylman SD. Theory and practice of crown and fixed partial prosthodontics (bridge). CV Mosby; 1970.170

The Ideal Retainer
 least amount of tooth
cutting and mutilation of
tooth contour and the least
number of surfaces
 Accurate marginal line
 without trauma to the pulp
or surrounding tissue
 Functional adaptation and
protect the tooth against its
fracture
 Cleansable
 Esthetic
 does not corrode or tarnish;
neither does it discolor the
abutment;
 capable of being prepared by
the average operator
 Rigidity to withstand requisite
load
Tylman SD. Theory and practice of crown and fixed partial
prosthodontics (bridge). CV Mosby; 1970.173

Factors affecting selection of retainers
Retention Cost
Preservation of
tooth structure
Length of
edentulous
span
Size position
and condition
of abutment
Patient
musculature
Type of
opposing
restoration
Esthetics
Age and sex of
patient
Existing caries/
caries index
Amount and
direction of
stress
Mouth hygiene
habits,diet of
the patient
prosthodontics (bridge). CV Mosby; 1970.174

CLASSIFICATION OF
RETAINERS
RETAINERS
EXTRA CORONAL
COMPLETE CROWNS
ALL METAL
ALL CERAMIC
METAL CERAMIC
PARTIAL VENEER
CROWNS
3/4TH CROWN
MESIAL HALF
CROWN
7/8TH CROWN
INTRA CORONAL
INLAY
ONLAY
RADICULAR/DOWEL
CAST POST
PRE FABRICATED
POST
BASED ON
LOCATION
Tylman SD. Theory and practice of crown and fixed
partial prosthodontics (bridge). CV Mosby; 1970.173

BASED ON TOOTH COVERAGE
FULL COVERAGE
RETAINER
PARTIAL
COVERAGE
RETAINER
CONSERVATIVE
RETAINERS
TWO OR MORE SURFACES INVOLVED
ALL FIVE SURFACES
INVOLVED
Tylman SD. Theory and
practice of crown and fixed
partial prosthodontics
(bridge). CV Mosby; 1970.345

BASED ON
MODE OF
RETENTION
ENCIRCLING
TOOTH
MAILNY BY
GROOVES
DOWEL PINS/POST
IN ROOT CANAL
RESIN BONDED

BASED ON
MATERIAL BEING
USED
ALL METAL NON
METAL(CERAMIC/ACRYLIC)
COMBINED(VENEERED/FULL
VENEERED
NEWER MATERIALS- PEEK

prosthodontics (bridge). CV Mosby; 1970.172,176

Full coverage retainers
 Fabricated like a cap
 for extensively damaged teeth
 most retentive and ideal retainers
 can resist masticatory forces in all directions

All metal retainers All ceramic retainers
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of
fixed prosthodontics. Quintessence Publishing Company; 1997 Jan. 352,383

ALL METAL RETAINERS
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-
Book. Elsevier Health Sciences; 2015 Jul 28.(page no.204, 211)

Rosenstiel SF, Land
MF, editors.
Contemporary Fixed
Prosthodontics-E-
Book. Elsevier Health
Sciences; 2015 Jul
28.(page no.202,204)

Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page no.215)
PREPARATION

Rosenstiel SF, Land MF, editors.
Contemporary Fixed Prosthodontics-
E-Book. Elsevier Health Sciences;
2015 Jul 28.(page no.214)

METAL CERAMIC RETAINERS
Book. Elsevier Health Sciences; 2015 Jul 28.(page no.225,229)

ALL CEARMIC RETAINERS
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.264,271)

Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-
E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.263)

PARTIAL
COVERAGE
RETAINER
Shillingburg HT, Hobo S, Whitsett LD, Jacobi
R, Brackett SE. Fundamentals of fixed
prosthodontics. Quintessence Publishing
Company; 1997 Jan.299 and 388
intact surface of tooth structure
should not be covered by a
crown if its inclusion is not
essential to the retention,
strength, or esthetic result of the
definitive restoration.
technician can’t exactly
duplicate texture and
appearance of untouched
enamel.
A full coverage crown is about
2.5 times as likely to have a
pulpal problem as One with a
partial coverage crown
conservative restoration
Gingival health - supragingival
margin

TYPES OF
PARTIAL
COVERAGE
RETAINERS
•ANTERIOR
•POSTERIOR
•PIN MODIFIED
•REVERSE- LOWER POSTERIOR TEETH
THREE QUARTER
CROWNS
•only used for the upper 1st molar.SEVEN EIGTH
CROWNS
•parallel long pins prepared in the lingual or palatal
surface
PIN LEDGE
CROWNS
•indicated for mesially tilted tooth.
PROXIMAL
HALF CROWNS
Shillingburg HT, Hobo S,
Whitsett LD, Jacobi R,
Brackett SE.
Fundamentals of fixed
prosthodontics.
Quintessence Publishing
Company; 1997 Jan.299
and 401

Advantages
 Margin is accessible to the dentist for finishing and to the patient
for cleaning.
 Less restoration margin is in proximity to the gingival crevice,
reducing the possibility of periodontal irritation.
 An open-faced partial coverage crown is more easily seated
completely during cementation, whereas a full coverage crown
tends to act like a hydraulic cylinder containing a highly viscous
fluid
 With some of the margin visible, complete seating of a partial
coverage crown is more easily verified.
 If an electric pulp test ever needs to be conducted on the tooth,
a portion of enamel is unveneered and accessible.
Shillingburg HT, Hobo S, Whitsett
LD, Jacobi R, Brackett SE.
prosthodontics. Quintessence
Publishing Company; 1997
Jan,388
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015
Jul 28.(page no.230)

 preparation feature must be
substituted to compensate for the
retention and resistance lost when
an axial surface is not covered.
 most commonly used feature is a
groove (maximum effectiveness-
grooves must have definite lingual
Walls)
fixed prosthodontics. Quintessence Publishing Company; 1997 Jan,389

INDICATIONS
 Intact or minimal
restored teeth
 Normal anatomic
clinical crown
 Teeth with adequate
labiolingual thickness
CONTRAINDICATIONS
 Teeth with short clinical crowns
 Thin teeth bucco-lingually
 Teeth that are proximally bulbous
 Poorly aligned tooth
 Bad oral hygiene and high caries index
 Retainers for long span bridges
 Endodontically treated teeth
 Malformed teeth
 Are not as retentive as complete coverage retainers.
 There is a limited display of metal.
 Tooth preparation is difficult because only limited
adjustments can be made in the path of placement.
DISADVANTAGES
Book. Elsevier Health Sciences; 2015 Jul 28.(page no.240)

Maxillary posterior three quarter
crowns
Rosenstiel SF, Land MF, editors. Contemporary
Fixed Prosthodontics-E-Book. Elsevier Health
Sciences; 2015 Jul 28.(page no.241)

Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences;
2015 Jul 28.(page no.243,244)

Rosenstiel SF, Land MF, editors. Contemporary Fixed
Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul
28.(page no.245)
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 398

MAXILLARY MOLAR

Shillingburg HT, Hobo S, Whitsett
LD, Jacobi R, Brackett SE.
prosthodontics. Quintessence
Publishing Company; 1997
Jan,399
Three-quarter crown preparation on a
mandibular molar or premolar
 many features found in the preparation of a maxillary tooth
 biggest difference is the location of the occlusal finish line on the
facial surface, which is gingival to occlusal contacts.
 serves the same purpose as the offset on the maxillary preparation,
tying the grooves together and strengthening the nearby facio-
occlusal margin.
 There is no need for an offset on the lingual inclines of the
mandibular facial cusps.

MANDIBULAR POSTERIOR TEETH THREE
QUARTER CROWN
Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page
no.248)

Three quarter crowns with proximal boxes
 more retentive than a standard preparation with
grooves
 but boxes are very destructive.
 justified only if there has been proximal caries or
previous restorations.
 A less destructive way to augment retention and
resistance is to use four grooves which is not
significantly less retentive than two boxes
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE.
Fundamentals of fixed prosthodontics. Quintessence Publishing
Company; 1997 Jan,399

Seven eighth crowns
 Vertical distofacial margin is positioned slightly
mesial to the middle of the facial surface
 Esthetics are good because the veneered
distofacial cusp is obscured by the mesiofacial
cusp.
 resistance is better than that of the three-quarter
crown.
 Accessible location of the distofacial finish line
makes the preparation easy to perform.
 Margin finishing by the dentist and cleaning by the
patient are also facilitated.
prosthodontics. Quintessence Publishing Company; 1997 Jan,400

 Used on any posterior tooth
needing a partial coverage
restoration where the distal cusp
must be covered.
 most commonly used on maxillary
molars, but it also can be placed
on mandibular premolars and
molars.
 for restoring teeth with caries or
decalcification on the distal aspect
of the facial surface, and it is an
excellent fixed partial denture
retainer.

PREPARATION OF
SEVEN EIGTH
CROWN
Contemporary Fixed Prosthodontics-E-
Book. Elsevier Health Sciences; 2015 Jul
28.(page no.246)

REVERSE THREE QUARTER CROWNS
 used on mandibular molars to preserve an intact
lingual surface
 abutments with severe lingual inclinations,
preventing the destruction of large quantities of
tooth structure that would occur if a full
coverage crown were used.
 The grooves at the linguoproximal line angles are
joined by an occlusal offset on the facial slope of
the lingual cusps.
 Closely resembles a maxillary three-quarter
crown preparation because the axial surface of
the nonfunctional cusp is uncovered

PROXIMAL HALF CROWN
A heavy channel or
occlusal offset connects
the grooves to strengthen
the disto-occlusal margin.
An occlusal isthmus
augments retention and
rigidity.
Company; 1997 Jan,400
three-quarter crown that is
rotated 90 degrees, with
the distal rather than the
facial surface left intact
tilted mandibular
molar fixed partial
denture abutment
A countersink
in the distal
channel helps
resist mesial
displacement.
excellent hygiene and a low
incidence of interproximal caries
Blemish on distal
surface
mesial surface
parallels the path of
insertion of the mesial
abutment
. Clearance of 1.5 mm is obtained from
occlusal reduction terminates at the distal
marginal ridge, with little or no reduction of
the mesial cusps
Grooves
paralleling the
mesial surface
are placed in
the facial and
lingual axial
walls.

short-span fixed partial dentures on
restoration- and caries-free abutments.
Wellaligned, thick, square anterior teeth with a
large faciolingual bulk of tooth structure
A well-executed standard three-quarter
crown on a maxillary incisor or canine
need not show much metal.
ANTERIOR THREE
QUARTER CROWNS

(1) path of
insertion and
groove
placement
(2) placement
and
instrumentation
of extensions
RESTORATION WITH MINIMAL
DISPLAY OF METAL
The path of insertion of an
anterior three-quarter
crown parallels the incisal
one-half to two-thirds of
the labial surface, not the
long axis of the tooth.
gives grooves a slight lingual
inclination
Placing their bases more
apically and labially and
making the grooves longer
If the
grooves
incline
labially, the
labioincisal
corners are
overcut,
displaying
metal. The
bases of the
grooves
then move
lingually,
becoming
shorter and
less
retentive
usually a pinmodified three-quarter crown in which metal coverage is minimized using pins.
Shillingburg HT, Hobo S, Whitsett LD,
Jacobi R, Brackett SE. Fundamentals of
fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan,403,404

small football-shaped
and coarse-grit
ballshaped
diamonds.
Incisal reduction: long
needle diamond.
Lingual axial reduction:
tapered torpedo
diamond.
Proximal axial
reduction: long
needle and tapered
torpedo
diamonds.
Axial finishing: fine-grit
tapered torpedo
diamond.
Proximal grooves:
no. 169L and 170L
burs.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R,
Brackett SE. Fundamentals of fixed
prosthodontics. Quintessence Publishing
Company; 1997 Jan,405,406,407

Incisal offset: no. 171L bur. Incisal bevel: fine-grit
flame diamond and no.
170L bur.
Proximal extensions are done with
thin diamonds or hand instruments
with a lingual approach to minimize
the display of metal. Use of a large
instrument or a labial approach will
result in overextension and an
unsightly display of metal.
FINISHING WITH NO.169 L
BUR
Brackett SE.
prosthodontics.
Quintessence
Publishing Company;
1997 Jan,411

PIN MODIFIED THREE QUARTER
CROWNS
 Esthetic modification - retainer of choice on
unblemished teeth used as fixed partial
denture abutments in esthetically critical
areas
 short-span fixed partial dentures
 splint retainers.
 repairing incisors and canines with severe
lingual abrasion
• not be used on teeth with caries or restorations,
on surfaces that are not to be covered, or in
mouths with extensive caries
• small, thin, malpositioned, or that have large
pulps
preserves the facial surface and one proximal
surface
minimal subgingival margins
Periodontally preferable to a full crown
unsightly display of metal is avoided without
resorting to a destructive full veneer metal-
ceramic restoration.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence Publishing Company; 1997 Jan,413,414

 Pins are likely to produce less retention, and pin-retained castings are less
retentive than standard three-quarter crowns.
 Greater the number, depth, or diameter of pins, the greater the
retention.39 The pinmodified
 An old restoration that was revived in the 1960s by the development of
small twist drills to make pinholes and nylon bristles to accurately
reproduce them.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals
of fixed prosthodontics. Quintessence Publishing Company; 1997 Jan,408

PREPARATION OF
PIN HOLES
 These pins should be 4 mm deep for optimum
retention and resistance
 cautious, when extending to the full depth in
areas where limited tooth structure is
available.
 followed with a no. 169L carbide bur, which is
0.6 mm in diameter at its tip and has a slight
taper so that its diameter approaches 0.9 mm
at its widest .
 Nylon bristles, which are ideally 25 to 50 μm
smaller in diameter than the drill, are placed in
the pinholes because the pinholes are too
small to be reproduced by impression
material.

 The nylon bristles easily placed with a flame, should have a
retentive feature on their protruding ends to allow them to
be picked up during the impression
 Impression material surrounds the pin and incorporates it
into the impression. When the impression is poured, the
nylon bristles protruding from it reproduce the pinholes.
 A monofilament nylon fishing line cut to an appropriate
length and of the appropriate diameter is used. One
manufacturer (Momoi) sells a 30-lb test monofilament nylon
line (Diamond Hi-Catch Leader Line) with a diameter of
0.59 mm, which is 85 μm smaller in diameter than the 0.675-
mmdiameter twist drill.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R,
Brackett SE. Fundamentals of fixed prosthodontics.
Quintessence Publishing Company; 1997 Jan,409

 Serrated pins produce more retention than smooth pins.
 Lengths of the same size monofilament nylon line as used for the
impression (ideally 25 to 50 μm smaller than the pinholes in the stone cast),
which have been very slightly serrated on the last 2 mm with a bur, are
incorporated into the wax pattern.
 The bur should not be used around the base of the bristles to avoid weak
areas there. The pinholes in the cast must first be carefully enlarged by
hand-twisting the no. 169L bur so that the bristles will slide into the pinhole
and will be removable with the wax pattern.
 These bristles must also have a retentive feature on their protruding end,
placed with a flame, to be incorporated into the wax pattern.
 The resulting pins in the casting are ideally 50 to 100 μm smaller than the
original pinholes in the preparation. In this example, they would be 85 μm
smaller.

 Pins should be at least 2.0 to 3.0 mm long.
 Adequate pin length is essential to retention, and short pins will cause the failure of a
conservative fixed partial denture.
 These are very destructive failures because the pinholes become channels for oral fluids and
microorganisms to penetrate deep into the tooth. Considerable damage may occur before
a loose retainer is detected.
 If adequate pinhole depth is not possible, a different retainer design should be used.

Lingual
reduction:
small coarse-
grit football-
shaped
diamond.
Incisal bevel:
medium-grit
long needle
diamond.
Lingual axial reduction: coarse-grit tapered
torpedo diamond.
Proximal axial
reduction: medium-grit
long needle and
coarse-grit
tapered torpedo
diamonds.
Axial finishing: fine-grit
tapered torpedo
diamond
Proximal grooves: no.
169L and 170L burs.
Proximal flares: fine-grit
flame diamond and bur.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan,416-19

PIN HOLES

Ledge, offset,
and trough: no.
170L bur.
Incisal bevel: fine-
grit flame
diamond and bur.
Pinholes: no. ½
round bur and
0.675-mm twist
drill.
Brackett SE.
prosthodontics.
Company; 1997
Jan,422,423

Book. Elsevier Health Sciences; 2015 Jul 28.(page no.251-253)

Rosenstiel SF,
Land MF, editors.
Contemporary
Fixed
Prosthodontics-E-
Book. Elsevier
Health Sciences;
2015 Jul 28.(page
no.252-254)

Prosthodontics-E-Book. Elsevier Health Sciences; 2015
Jul 28.(page no.254-255)

Rosenstiel SF, Land
MF, editors.
Contemporary
Fixed
Prosthodontics-E-
Book. Elsevier
Health Sciences;
2015 Jul 28.(page
no.256)

PIN LEDGE PREPARATION
It is a technique that
employs parallel long
pins prepared in the
lingual or palatal
surface of the clinical
crown, in order to
increase retention of the
restoration.
• These restorations
used the both grooves
and pins to improve
retention
2015 Jul 28.(page no.255)

Rosenstiel SF, Land MF,
editors. Contemporary Fixed
Prosthodontics-E-Book.
Elsevier Health Sciences; 2015
Jul 28.(page no.256,257)

28.(page no.257-59)

Jul 28.(page no.259
0

28.(page no.261)

Rosenstiel SF, Land
MF, editors.
Contemporary Fixed
Prosthodontics-E-
Sciences; 2015 Jul
28.(page no.261)

INTRA CORONAL
RETAINERS
Largely or entirely confined within the contour
of the crown and whose retentive forces are
effective within the body of the tooth; its
exposed surface area is generally less than that
lying within the cavity.
•SMALL CLASS II RESTORATION
•severely worn dentition when
the teeth are otherwise
minimally damaged
•Replacement of an MOD
amalgam restoration
INDICATIONS
•caries or existing restorations
extend beyond the facial or
lingual line angles, are
contraindicated
•unless pins are used to
supplement retention and
resistance
CONTRA
INDICATIONS
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 460

prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 462-65

MO INLAY PREPARATION
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics.
Quintessence Publishing Company; 1997 Jan.299 and 466

METAL INLAY VARIATIONS
CLASS V INLAY ON
MAXILLARY MOLAR
CLASS III INLAY ON
CANINE
CLASS I INLAY
ON
MANDIBULAR
MOLAR
Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 467-68

MOD ONLAY
PREPARATION
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence Publishing Company; 1997
Jan.299 and 469-70

FEATURES AND
FUNCTIONS
Brackett SE.
prosthodontics.
and 474
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 471-72

MOD ONLAY PREPARATION
Planar occlusal
reduction: round-
end tapered
diamond and no.
171L bur.
Functional cusp
bevel: round-end
tapered diamond
and no. 171L
bur

OCCLUSAL SHOULDER
no. 171L bur.
Isthmus: no. 171L bur.
Proximal box: no.
169L and no. 170L
burs.
Proximal flares:
flame diamond
and flame bur.
Gingival
bevel:
flame
diamond
and
flame bur.
Facial and lingual
bevels: flame diamond
and no. 170L bur.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 475-79)

RESIN BONDED FIXED PARTIAL
DENTURES
development of acid etching of
enamel to improve the retention of
resin
Buonocore in 1955
means of attaching fixed
partial dentures to teeth by
less destructive means
described the attachment
of an acrylic resin pontic to
an unprepared tooth using a
composite bonding resin
Ibsen 1974

Development of resin retained FPDs
 The addition of a metal substructure and wings,
or retainers, extending onto the abutment teeth
was a logical progression
Metalsurfacefinishing
technique
Rochette
Maryland
Virginia
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.685)

BONDED PONTICS
 The earliest resin-retained prostheses were extracted natural teeth or
acrylic teeth used as pontics bonded to the proximal and lingual surfaces
of abutment teeth with composite resin.
 The composite resin connectors were brittle and required supporting wire
or a stainless steel mesh framework. These
 limited to short anterior spans and had a limited lifetime with degradation
of the composite resin bond to the wire or mesh and subsequent fracture.
 presented to patients as short-term replacements.

CAST PERFORATED RESIN-RETAINED FPDS
(MECHANICAL RETENTION)
ROCHETTE 1973
• 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
• began using FPDS with cast-perforated metal retainers bonded to abutment teeth and metal-
ceramic pontics to replace missing anterior teeth.
• Extend the framework to cover a maximum area of the lingual surface, suggested little or no
tooth preparation.
• Patient selection limited to mandibular teeth or situations with an open occlusal relationship.
• bonded with a heavily filled composite resin as a luting medium.
LIVADITIS
• expanded to replacement of posterior teeth
• Perforated retainers were used to increase resistance and retention.

LIMITATIONS
Weakening of
the metal
retainer by the
perforations
Exposure to wear
of the resin at the
perforations
Limited adhesion
of the metal
provided by the
perforations

ETCHED CAST RESIN-RETAINED FPDS
(MICROMECHANICAL RETENTION-"MARYLAND
BRIDGE")
Thompson and Livaditis at
the University of Maryland
work of Tanaka et al" on pitting
corrosion for retaining acrylic
resin facings
metal etching studies of Dunn
and Reisbick
developed
a technique
for the
electrolytic
etching of
Ni-Cr and
Cr-Co alloys
Resin to
etched
enamel
bond
Resin to
etched
metal
bond
Doukoudakis et al.
stable aqua regia
gel was substituted
for
electrochemical
etching
McLaughlin
Develop a faster
technique
usingcombined
solution of sulfuric
and hydrochloric
acids
2015 Jul 28.(page no.675)

Advantages
 The retainers can be thinner and still
resist flexing.
 The oral surface of the cast retainers is
highly polished and resists plaque
accumulation.
Disadvantages
 Lack of attention to detail can result in
electropolishing or surface
contamination
 With time, both severely degrade
bond strengths in a moist environment.
Jul 28.(page no.676)

 Proper etching requires evaluation of the
alloy surface with a scanning electron
microscope.
 Air abrading metal with 250-ìm abrasive
increases bonding strength remarkably
when used in conjunction with silane
The acid solution and technique
•specific to the nonberyllium nickel-chromium alloy
Thompson et al
•10% sulfuric acid at 300 mA/cm2, followed by the
same cleaning procedures, would produce similar
results with a beryllium-containing nickel-
chromium alloy.
tremendous variability from one
laboratory to another and from one
retainer to another

MACROSCOPIC MECHANICAL RETENTION
RESINRETAINED
FPDS ("VIRGINIA BRIDGE")
"
Virginia Commonwealth
University School of
Dentistry
Adequate bond strengths
thickness of the casting must be
increased to allow for the undercut
thickness
Moon and Hudgins et al
Surface
treatments
Air abrasion with
aluminum oxide
prepare Co-Cr
castings for
bonding with 4-
methacryloxyethyl
trimellitate
anhydride (4-
META) resin.
Nickel-chromium alloys required oxidation with a dilute solution of sulfuric acid
and potassium manganate as well.
28.(page no.677)

“lost salt crystal" technique.
salt crystals are dissolved from the surface of the pattern
Application of a resin pattern
Pattern investment
Within the outlines of the retainers - salt crystals sprinkled
150 t0 250 micrometer Uniform monolayer
. 0.5-mm border without crystals at
periphery
Working cast - abutments are coated with a model spray.
lubricant is applied
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.678

An alternative technique for
macroscopic retention
 cast mesh pattern (nylon) on the
internal surface of the retainers
 technique sensitive
 adequate retention with a
resulting thick lingual casting.
 The cast mesh and the lost salt
crystal method have been
supplanted by direct adhesion
with resin
 possible for most casting alloys if
the correct surface treatment is
provided

CHEMICAL BONDING RESIN-RETAINED FPDS
ADHESION BRIDGES
adhesive systems for direct
bonding of metal
Super bond
formulation
of a methyl methacrylate polymer
powder and
MMA liquid modified with the adhesion
promoter
4-META (4-methacryloxyethyl-trimellitic
anhydride)
tri-nbutylborane
catalyst system ( added to the liquid
before combining with the powder)
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page
no.689)

Advantages
 highest initial bond strengths of any
adhesive resin system (base metal
alloys)
 lower elastic modulus and higher
fracture toughness when compared
to BISGMA-based resin cements ‘
 less brittleness and better clinical
results with less welladapted castings .
Disadvantages
 Hydrolytic stability of these bonds over
time depends on the alloy's Cr-Ni ratio
 poor clinical results with bonding high
gold alloy retainers to abutment teeth

BISGMA Based composite resin luting
cement
• modified with the adhesion promoter MDP
• Excellent bonds to airabraded Ni-Cr and Cr-Co alloys as well as tinplated gold and gold
palladium-based alloys.
• tensile bond to etched enamel (10 to 15 MPa) comparable to the traditional BISGMA low-film
thickness composites (e.g., Comspan and Conclude).
• combination of metal electrolytic etching, followed by application of an adhesive such as
Panavia, does not improve the tensile bond to the alloy and is actually slightly lower than the
bond of Panavia to airborne-particle-abraded sandblasted) base metal alloys
Rosenstiel SF, Land MF,
editors. Contemporary
Fixed Prosthodontics-E-
Sciences; 2015 Jul
28.(page no.690)

 The most recent version of Panavia,
Panavia F, is a dual cure system
(chemical and visible light) that
releases fluoride.
 incorporates a self-etching primer
system (ED Primer) for bonding to
enamel and dentin

TIN PLATING
 Tin-plating of noble alloys allows resin-to-metal bond
tensile bond strengths only slightly lower than those
for either the electrolytically etched or airabraded
 Ni-Cr-Be alloys (18 to 30 MPa). However, tensile bond
strengths are certainly greater than the bond to
etched enamel.
 particle abrasion of the alloy surface for adequate
tin nucleation sites
 Tin-plating can be completed in the dental
laboratory, chairside, or intraorally to achieve metal
bonding.
 Particle abrasion of the alloy surface just before the
plating procedure is critically important

TIN PLATING SYSTEM
tin amide solution- applied to the
metal surface with a saturated cotton
pledget held on the end of a battery-
powered probe (4 volts).
probe is grounded elsewhere on the
metal Tin-plating times are usually 5 to 10
seconds and produce a light gray
surface.
followed by copious rinsing with water
and drying;
adhesive resin is then applied.
.

 Particle abrasion of the alloy surface with 50 u alumina before bonding or
tin- plating not only creates a roughened, higher surface area substrate for
bonding, but it also creates a molecular coating of alumina."
 The alumina on the surface aids in oxide bonding of the phosphate-based
adhesive systems (e.g., Panavia to alloy surfaces)
 Studies of this bonding mechanism are also reinforced by laboratory data
on bonding to alumina and zirconia surfaces

 These adhesive systems have now shown nearly the same degree of long-
term clinical bonding (since 1983 in Japan) as the conventional
composites on etched metal (since 1981 in the United States).
 Laboratory data support their efficacy.
 Favorable findings for direct adhesion to metal make alloy etching and
macroscopic retention mechanisms obsolete.'-
 This simplifies the laboratory and clinical procedures for placement of resin-
retained FPDs
Book. Elsevier Health Sciences; 2015 Jul 28.(page no.695

Laboratory systems for adhesive
bonding resin to
metal
 flame application of a silica-carbon layer to the metal surface.
 This treated metal is then silane-coated, which provides a
surface to which composite resin will bond.
 The system (burneraspirator- timer and associated chemistry)
was initially marketed to the dental laboratory industry as the
Silicoater.
 evolved to an oven method to bake the silica-carbon layer to
the alloy surface and is now called the Silicoater MD system.
 Subsequently, the critical aspects of sandblasting before
treatment in the oven have been investigated
Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page
no.696

ROCATEC SYSTEM
 metal surface is initially particle-abraded with
120 um alumina.
 followed by abrasion with a specialsilicate
particle-containing alumina
 second particle abrasion step deposits a
molecular coating of silica and alumina on the
alloy surface.
 Silane is then applied to the surface, making it
adhesive to composite resin.
28.(page no.696

DESIGN CONCEPTS
 cover as much enamel surface as
possible, as long as occlusion,
esthetics, or periodontal health are not
compromised
 The initial designs of etched cast
retainers included an "interproximal
wraparound" concept developed to
resist occlusal forces and provide a
broader area for bonding.
 Enamel preparations consisted of
creating occlusal clearance,
placement of occlusal/cingulum rests,
and lowering the lingual and proximal
height of contour, thus creating
proximal extensions
PROPER PATIENT
SELECTION
CORRECT
ENAMEL
MODIFICATION
FRAMEWORK
DESIGN
Elsevier Health Sciences; 2015 Jul 28.(page no.691

 Frameworks should seat in an
occlusogingival direction and should have
no facial-lingual displacement
 contemporary design has improved
retention with well-placed and precise
grooves on abutment teeth
 Contemporary mouth preparations, in an
effort to minimize failures, do not preserve
as much tooth structure as their
predecessors; nevertheless, they are still
limited to enamel and adhere to
conservative design principles
Jul 28.(page no.689

Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page
no.691

E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.692,693

FABRICATION
PREPARATION OF ABUTMENT
TEETH
 A distinct path of insertion must exist
 Proximal undercuts must be removed to
provide "planes of metal" on the lingual
and proximal surfaces
 Occlusal rest seats and proximal
groove/slots must provide resistance
form
 definite and distinct gingival margin
should be established wherever possible
anterior teeth - similar in many ways to the
lingual reduction of pinledge preparation
amount of reduction is less because the enamel
must not be penetrated. If necessary, the
opposing teeth can be recontoured to increase
interocclusal clearance.
Jul 28.(page no.694

Bur selection
• chamfer or roundtipped diamond
Gingival margins and circumferential preparation
• Diamond / carbide inverted cone burr
Notches
• Fissure bur
Other retentive features (slots,grooves)
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.693

Occlusal marking
articlulating paper
Occlusal clearance
Football shaped
diamond
Lingual reduction
Football shaped
diamond
Counter sinks
Flat end tapered
diamond
Proximal reduction
(facial segment): flat-
end tapered diamond
Proximal reduction
(lingual segment): flat-
end tapered diamond.
Brackett SE. Fundamental
of fixed prosthodontics.
and 436-40

Lingual axial reduction:
round-end tapered
diamond
Cingulum groove: short
needle diamond
Proximal groove: short
needle diamond
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals
of fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299
and 440

Resin bonded abutment preparation
Maxillary
incisor
Mandibular
incisor
Canine Mandibular
1st premolar
Company; 1997 Jan.299 and 433-36

Quintessence Publishing Company; 1997 Jan.299 and 435

Elsevier Health Sciences; 2015 Jul 28.(page no.698

BONDING THE
RESTORATION
Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page
no.700

Quintessence Publishing Company; 1997 Jan.299 and 443,444

Brackett SE.
prosthodontics.
and 445,446

Intra radicular retainers
 Retention and resistance
to displacement from the
prepared root portion of
an endodontically treated
teeth
 While the root preparation
retains the post, the core
establishes retention and
resistance for a complete
veneer crown that restores
the pulp less tooth to
normal form and function.
post or dowel with an attached core

Post
Pre
fabricated
Tapered
Smooth
sided
Serrated Threaded
Parallel
Smooth
sided
Serrated Threaded
Custom
made
Deutsch AS, Musikant BL, Cavallari J, Lepley JB. Prefabricated dowels: a
literature review. Journal of Prosthetic Dentistry. 1983 Apr 1;49(4):498-503.

• All porcelain crown with a post that is detached and can be
placed on a prepared root end by cementation of both the
post in the root and the cementation of crown on the post
DETACHED
DOWEL CROWN
BY DAVIS
•A dowel retained crown made for an endodontically treated
tooth using porcelain facing.
RICHMOND
CROWN
•When the coronal portion of the remaining tooth is missing to a
point below gingiva and it is impossible to adapt the crown and
root face, a cast metal base is interposed between the base of
the crown and root face.
• This cast base is rigidly attached to the dowel.
DETACHED POST
CROWN WITH A
CAST BASE

 It seems reasonable to concern ourselves with
proper diagnosis and meticulous execution of
properly designed retainers, rather than to pit one
type of retainer against another.
 After all retainers are our tools like articulators. we
must tailor our treatment plan to the specific needs
of our individual patient rather than to fit our
patient to our favourite method of treatment.
CONCLUSION

Stokholm R, Isidor F. Resin-bonded inlay retainer
prostheses for posterior teeth. A 5-year clinical study.
International Journal of Prosthodontics. 1996 Mar 1;9(2).
This study
evaluated
posterior
resin-
bonded
prostheses
using
inlays as
retainers
Thirty-nine patients missing at least one
premolar or first molar received 51
resin-bonded fixed partial dentures
with high noble alloy inlay retainers
and a metal ceramic pontic. Resin
luting material bonding to the
framework was secured by the
Silicoating method (24 fixed partial
dentures), lost sugar crystal method
(13 fixed partial dentures), or tin
plating (14 fixed partial dentures).
Clinical examinations were performed
1 week, 1 month, 6 months, 1 year, 2
years, and 5 years after cementation
RELATED ARTICLES
. None of the fixed partial
dentures with silicoating or sugar
crystal impressions lost retention,
whereas two of the tin-plated
fixed partial dentures required
replacement. Resin-bonded
inlay-retained prostheses appear
to be a favorable alternative to
other types of fixed partial
dentures.

Trier AC, Parker MH, Cameron SM, Brousseau JS.
Evaluation of resistance form of dislodged crowns and
retainers. The Journal of prosthetic dentistry. 1998 Oct
1;80(4):405-9.
This investigation evaluated
the resistance form of
abutments of crowns or
retainers that have been
dislodged to determine the
clinical correlation between
restoration dislodgment and
lack of resistance form in the
preparation.
Dies were fabricated from
single crowns and retainers of
fixed partial dentures that
came loose and evaluated
for resistance form. A total of
44 abutments were
evaluated and included 1
incisor, 15 premolars, and 28
molars. Data from a previous
study on the percentage of
abutments lacking resistance
form for restorations leaving a
large dental laboratory was
used for comparative
statistical tests.
The clinical dislodgment of
cast restorations is associated
with the lack of resistance
form in the preparations. In
this study, there was a
relationship between clinical
success or failure and the all-
or-none nature of resistance
form; dislodged crowns
come almost exclusively from
preparations with tapers that
did not provide resistance
form

Outcome of bonded vs all-ceramic and
metal- ceramic fixed prostheses for
single tooth replacement.
 Karl M et al, Eur J Oral Implantol, 2016;9 Suppl 1:S25-44
 The conventional treatment of a single missing tooth is most
frequently based on the provision of a fixed dental prosthesis (FDPs).
to compare resin-
bonded, all-
ceramic and
metal-
ceramic FDPs
based on existing
evidence.
Metal-ceramic FDPs still show the highest
survival rates of all tooth-supported
restorations.
Depending on the ceramic system used,
all-ceramic restorations may reach
comparable survival rates while the
technical complications, i.e. chipping
fractures of veneering materials in
particular, are more frequent.
Resin-bonded FDPs can be
seen as long-term
provisional restorations with
the survival rate being
higher in anterior locations
and when a cantilever
design is applied.
Inlay-retained FDPs and the
use of fiber-reinforced
composites overall results in
a compromised long-term
prognosis.
Recently advocated
monolithic zirconia
restorations bear the risk of
low temperature
degradation

All-ceramic inlay-retained fixed dental
prostheses for replacing posterior missing
teeth: A systematic review
 Raquel et al, J Prosthodont Res, 2018 Jan;62(1):10-23
to evaluate the current
status of all-ceramic inlay-
retained fixed dental
prostheses (CIR-FDPs) for the
replacement of posterior
teeth.
AIM
They concluded
that, a three-unit
CIR-FDP is a viable
treatment option
for replacing a
posterior missing
tooth.
Appropriate case
selection, abutment
preparation and
luting procedures
may be decisive for
clinical success.
Zirconia-based CIR-FDPs may be
recommended for restoring
posterior single missing teeth,
although the prosthesis/tooth
bonded interface has yet to be
improved.
The addition of lateral wings to the
classical inlay preparation seems
promising.
The weakest parts of CIR-FDPs are
the connectors and retainers,
while caries and endodontic
problems are the most common
biological complications.
The fabrication of CIR-FDPs with
monolithic zirconia may eliminate
chipping problems.

Predictability of resin bonded bridges – a
systematic review
 Balasubramaniam et al, Br Dent J, 2017 Jun 9;222(11):849-858
to evaluate the
survival rate of
resin bonded
bridges (RBBs) and
understand the
relationship
between various
prognostic factors
and survival rate.
AIM
Debonding of the restoration (78%) is the most common
type of failure followed by porcelain fracture (13%).
Bridges cemented with Panavia showed the highest survival
rate (67%) among the luting cements analysed for 5 years.
Retentive tooth preparation, preparation confined to
enamel, silicoating, supra gingival margins, Ni-Cr or Co-Cr
alloys and no occlusion on pontic in lateral excursions have
been reported to be associated with better survival rates.
Anterior RBBs were found to be more retentive than posterior
RBBs

Comparison of Metal-Ceramic and All-
Ceramic Three-Unit Posterior Fixed Dental
Prostheses: A 3-Year Randomized Clinical Trial.
 Nicolaisen et al, Int J Prosthodont, 2016 May-Jun;29(3):259-64
to compare the 3-year clinical
outcome of metal-ceramic fixed
dental prostheses (MC-FDPs) and
zirconia all-ceramic fixed dental
prostheses (AC-FDPs) replacing a
posterior tooth.
AIM
34 patients with a
missing posterior tooth
were chosen to receive
either a MC-FDP (n = 17)
or an AC-FDP (n = 17).
evaluated at baseline
and yearly until 3 years
after cementation
survival rates for MC-FDPs
and AC-FDPs were 100%.
success rate was 76% and
71% for MC-FDPs and AC-
FDPs, respectively.
3 technical complications
were observed in the MC-
FDP group and 5 in the AC-
FDP group, all chipping
fractures of
the ceramic veneer.
1biologic complication in
the MC-FDP group (an
apical lesion) was observed
RESULTS

REFERENCES:
 A.E. Kahn, Partial Versus Full Coverage. J. Prosthet. Dent. 10:167-178, 1960
 Johnstons, Modern Practice in Fixed Prosthodontics 4th edition 1986.
 T.Shillinburg.Fundamentals of Fixed Prosthodontics, III edition
 T.Shillinburg.Fundamentals of Fixed Prosthodontics, IV edition
 Rosenstiel, Land, Fujimoto. ContemperoryFixed Prosthodontics, III edition

 Balasubramaniam et al , Predictability of resin bonded bridges – a
systematic review. Br Dent J, 2017 Jun 9;222(11):849-858.
 Shah et al, The Use of All-Ceramic Resin-Bonded Bridges in the Anterior
Aesthetic Zone. Dent Update, 2017 Mar;44(3):230-2, 235-8.
 Raquel et al, All-ceramic inlay-retained fixed dental prostheses for
replacing posterior missing teeth: A systematic review. J Prosthodont Res,
2018 Jan;62(1):10-23.
 Karl M et al, Outcome of bonded vs all-ceramic and metal- ceramic fixed
prostheses for single tooth replacement. Eur J Oral Implantol, 2016;9 Suppl
1:S25-44.

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