Retainers in fpd FINAL VERSION pptx

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
 RETAINERS FOR SEVERELY DEBILITATED
TEETH
 RETAINERS FOR PERIODONTALLY
COMPROMISED TEETH
 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

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

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
Nallaswamy D. Textbook of
prosthodontics. JP Medical Ltd; 2017
Sep 30.643

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)

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
Elsevier Health Sciences; 2015 Jul 28.(page no.225,229)

Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier
Health Sciences; 2015 Jul 28.(page no.228)

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)

ALL ACRYLIC RETAINER
 They are used for long-term temporary fixed partial
dentures.
 They are not indicated for permanent restorations
editors. Contemporary
Fixed Prosthodontics-E-
Sciences; 2015 Jul
28.(page no.381

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
 complete seating - more easily verified (some of the margin visible)
 electric pulp test can be conducted
Shillingburg HT, Hobo S, Whitsett
LD, Jacobi R, Brackett SE.
Fundamentals of fixed
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)

Compansaton to the loss of retention and
resistance (axial surfaces not covered)
 most commonly used feature is a groove (maximum
effectiveness- grooves must have definite lingual Walls)
prosthodontics. Quintessence Publishing Company; 1997 Jan,389
(a) Definite lingual walls resist displacement
(b) An oblique lingual wall offers poor resistance
(c) An undermined facial enamel plate may fracture.
(d) A groove that is too far lingual does not provide bulk of
metal to support the margin.

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
 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

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

28.(page no.243,244)

Rosenstiel SF, Land MF, editors. Contemporary Fixed
Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul
28.(page no.245)
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

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.

 Used on any posterior tooth needing a
partial coverage restoration where the
distal cusp must be covered.
 most commonly on maxillary molars
(also 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
Rosenstiel SF, Land MF, editors. Contemporary
Fixed Prosthodontics-E-Book. Elsevier Health

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
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics.
Quintessence Publishing Company; 1997 Jan,400

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.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE.
Fundamentals of fixed prosthodontics. Quintessence Publishing
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

Lingual reduction: 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.
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.
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
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence Publishing Company; 1997 Jan,413,414

PREPARATION OF PIN HOLES AND
IMPRESSION MAKING
 4 mm deep(optimum retention and resistance)
 cautious, when extending to the full depth in areas where limited tooth structure is available.

 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. Fundamentals
of fixed prosthodontics.
Company; 1997
Jan,422,423

Quintessence Publishing Company; 1997 Jan,423

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

Contemporary Fixed
Prosthodontics-E-Book. Elsevier
Health Sciences; 2015 Jul
28.(page no.252-254)

28.(page no.254-255)

Rosenstiel SF, Land
MF, editors.
Contemporary Fixed
Prosthodontics-E-
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
28.(page no.255)

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

Rosenstiel SF, Land
MF, editors.
Contemporary Fixed
Prosthodontics-E-
Book. Elsevier
Health Sciences;
2015 Jul 28.(page
no.257-59)
A, Modified pinledge preparation with a proximal
groove. The path of withdrawal of this
groove is compatible with the preparation as well as
with the pinholes. B, A similar preparation on a
maxillary canine. Note two similarities with the three-
quarter crown: the heavy lingual chamfer and the
incisal offset blending into the proximal groove to
provide additional bulk for reinforcement.

28.(page no.259
0

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
Occlusal outline: no. 170L
bur
Undermining marginal
ridge: no. 169L bur
Proximal box: no. 169L and
170L burs.
Gingivoaxial
groove: gingival
margin trimmer.
Proximal flares:
coarse-grit flame
diamond
Gingival bevel:
coarse-grit flame
diamond.
Isthmus bevel:
fine-grit flame
diamond.
Bevel and
flare
finishing:
flame bur.

MO INLAY PREPARATION
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
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
474
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence Publishing

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)

TELESCOPIC RETAINERS
 When the path of insertion of the fixed partial denture does not
coincide with the long axis of the abutment tooth
 Fabrication of two copings, one over the other
 Internal or primary coping functions to modify the morphology
of the tooth. Hence
 primary coping helps to change the path of insertion
 secondary coping is designed to fit over the primary coping
along the new path of insertion.
 Accurate parallelism of the copings is necessary (obtained by
the use of milling machines)

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
Metalsurfacefinishingtechnique
Rochette
Maryland
Virginia
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.685)

BONDED PONTICS
 (earliest) extracted natural teeth or acrylic teeth used as pontics bonded to the
proximal and lingual surfaces of abutment teeth with composite resin.
 brittle and required supporting wire or a stainless steel mesh framework
 limited to short anterior spans
 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.
• used 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 using
combined solution
of sulfuric and
hydrochloric acids
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.
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 RESIN
RETAINED
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.
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-
E-Book. Elsevier Health Sciences; 2015 Jul 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.
 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)

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
editors. Contemporary Fixed
Prosthodontics-E-Book.
Elsevier Health 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
 particle abrasion of the alloy surface for adequate tin
nucleation sites(just before the plating procedure is
critically important)
 Tin-plating can be completed in the dental laboratory,
chairside, or intraorally to achieve metal bonding.

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
• Time - 5 to 10 seconds
• produce a light gray surface.
• followed by copious rinsing with water
and drying;
• adhesive resin is then applied.
Prosthodontics-E-Book. Elsevier Health Sciences; 2015
Jul 28.(page no.693)

 Particle abrasion of the alloy surface with 50 u alumina before bonding
 tin- plating not only creates a roughened, higher surface area substrate for
bonding, but it also creates a molecular coating of alumina."
 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
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 systems for adhesive
bonding resin to metal
 flame application of a silica-carbon layer to the metal surface.
 Treated metal is then silane-coated, which provides a surface to
which composite resin will bond.
 system (burner aspirator- 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.
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 special silicate 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.
Book. Elsevier Health Sciences; 2015 Jul 28.(page no.696

Elsevier Health Sciences; 2015 Jul 28.(page no.689
DESIGN CONCEPTS
INITIAL DESIGNS
 interproximal wraparound
 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
 Frameworks should seat in an
occlusogingival direction and should have
no facial-lingual displacement
CONTEMPORARY DESIGNS
 Improved retention with well-placed and
precise grooves on abutment teeth
 Do not preserve as much tooth structure
as their predecessors; nevertheless, they
are still limited to enamel and adhere to
conservative design principles

Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.690-694)

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.
28.(page no.694

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. Fundamentals o
fixed prosthodontics.
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

Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 435

28.(page no.697)

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

BONDING THE
RESTORATION
Sciences; 2015 Jul 28.(page no.700

Company; 1997 Jan.299
and 445,446

RETAINERS FOR SEVERELY DEBILITATED
TEETH
Teeth with large areas of enamel
involvement may require full
coverage restorations regardless of the
amount of dentin that has been
destroyed.
A large central lesion may require a full
coverage restoration, but only after the
tooth is built up with a core.

Moderate central damage can be restored
with a restoration that
preserves and uses sound peripheral tooth
structure rather than destroying it.
Severe combined destruction will require a
core and a full coverage
restoration.
prosthodontics. Quintessence Publishing Company; 1997 Jan 486

PRINCIPLES OF SUBSTITUTION
No retentive features may be
cut into the vital core (center)
of the
tooth.
(a) Interproximal caries may preempt the use of a groove (dotted
line). (b) Use of a box in this situation accommodates caries removal and
provides retention.
Quintessence Publishing Company; 1997 Jan.486

prosthodontics. Quintessence Publishing Company; 1997 Jan.299489,490

Shillingburg HT, Hobo S, Whitsett LD,
Jacobi R, Brackett SE. Fundamentals of
fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.490and
491

(a) moderately damaged (eg, by an old MOD amalgam), a
standard MOD onlay
preparation or a three-quarter crown preparation with
boxes can be used
(b) If one cusp has been destroyed, a widened box with
groove augmentation can be used.
(c) half of the crown has been destroyed, grooves may
provide sufficient retention if the supragingival tooth
structure in which they are
placed has sufficient length. Pinholes may be added to the
preparation.
(d) If three or more cusps have been destroyed, a pin-
retained core should be
fabricated before proceeding to a full coverage cast
restoration.
(e) Extensive peripheral destruction often requires a full
coverage cast restoration if caries
has been controlled.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence Publishing Company; 1997
Jan.299 and 494 AND 495

Shillingburg HT, Hobo S, Whitsett LD,
Jacobi R, Brackett SE. Fundamentals of
fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299
and 498

RETAINERS FOR PERIODONTALLY
COMPROMISED TEETH
1.0-mm shoulder in the usual
position.
1.0-mm shoulder apical to the cementoenamel junction
additional destruction of axial tooth structure required to produce the
shoulder at this level.
Preparation for a metal-
ceramic crown on a maxillary
premolar
chamfer apical to the cementoenamel
junction. The amount of axial
reduction is similar to that required for a
shoulder at the usual position.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. Quintessence Publishing Company;
1997 Jan.299 and 551

wide gingival collar is used to
blend the root contour with
that
required for a ceramic veneer
of adequate thickness.
prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 551-559

Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals
of fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299
and 560-561

Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett
SE. Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 562-63
Facial view of a metal-ceramic crown on a
maxillary molar whose
mesiofacial root has been removed.
MAXILLARY MESIOFACIAL ROOT

MAXILLARY PALATAL ROOT
OCCLUSAL VIEW
The presence of palatal cusps on a maxillary molar
deprived of the
support of its palatal root would subject the tooth to
torquing forces (arrow)
that could tip the tooth palatally.
fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and
565-6

MAXILLARY FACIAL ROOTS
Occlusal contacts
should occur on
the palatal cusp tip.
There
should be minimal
occlusion facial to
the central groove
of the crown.
Brackett SE. Fundamentals of fixed prosthodontics.
Quintessence Publishing Company; 1997 Jan.299
and 568

MANDIBULAR HEMISECTION
The mesial root of a mandibular
second molar can effectively
extend the occluding segment of
the mandibular arch to serve as a
stop for the
opposing occlusion.
Fig
The distal root of a mandibular molar can serve as an abutment for
a shortspan prosthesis replacing the resected mesial root.
Company; 1997 Jan.299 and 568-570

The contact that obliterates the gingival
embrasures of restorations
placed on a hemisected molar (a) can be
alleviated in some cases by placing
shoulders on the interradicular segments
of the preparation that face each
other across the former furcation (b).
(a) If the roots are not separated
after resection, there will be no
gingival embrasure. (b)
Orthodontic movement is one
way of achieving
separation.
The mesial root of a
mandibular second
molar can be the
abutment
for a molar
replacement fixed
partial denture, but it
offers less than one-
third
of the support of an
unresected molar.

The crown placed over these
resected roots reestablishes
the
furcation(s) in metal.
fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and
571
Roots of one tooth can be
separated and prepared as
individual
teeth

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
Deutsch AS, Musikant BL, Cavallari J, Lepley JB.
Prefabricated dowels: a literature review. Journal
of Prosthetic Dentistry. 1983 Apr 1;49(4):498-503.

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.

 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.

Retainers in fpd FINAL VERSION pptx

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Ähnlich wie Retainers in fpd FINAL VERSION pptx

Ähnlich wie Retainers in fpd FINAL VERSION pptx (20)

Mehr von NAMITHA ANAND

Mehr von NAMITHA ANAND (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Retainers in fpd FINAL VERSION pptx

Hinweis der Redaktion