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RETAINERS IN
FIXED DENTAL
PROSTHESIS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

CONTENTSCONTENTS
PART IPART I
Introduction
Requirements of retainer
Criteria for selecting retainers
Classification
Full veneer crown retainer
Metal ceramic retainer
All ceramic crown retainer
Pinledge retainer
Partial veneer crown retainer

PART IIPART II
Resin bonded retainer
Rochette bridge
Maryland bridge
Virginia bridge
inlays
onlays
Radicular retainers
Failures in retainers
Conclusion
references

INTRODUCTIONINTRODUCTION
All fixed partial dentures are made up of
retainers that obtain support from the
abutment, pontics that replace the
missing tooth and connectors that
connect the pontics to the retainers
Retainer is defined as, part of fixed
partial denture which unites abutment
to the remainder of restoration

REQUIREMENTS OF RETAINERREQUIREMENTS OF RETAINER
Biocompatible
Withstand masticatory forces
Restore anatomy of the tooth
Pulp consideration
Strength: to resist deformation under
functional stresses
Esthetically acceptable
Maintain oral hygiene

CRITERIA FOR SELECTION OF RETAINERSCRITERIA FOR SELECTION OF RETAINERS
1. Degree of retention required
 Most important consideration
 Factors which effect retention are
a.Length of the span:
Longer the span greater the stress on
retainers, so the components of a bridge must
be stronger
b.Type of bridge required
Strong retainers are required for fixed-fixed
bridge than fixed-movable to withstand
stresses on cementing media

c. Strength of bite
It will vary with the age, sex and muscular
development of patient
Heavier bite requires stronger and thicker
metal to prevent failure of retainers
d.Tooth or teeth to be replaced
Size and position of pontic have a direct
effect on type of retainer
Eg: replacement of molar impart great stress
to abutment than lower central

e. Articulation
-influences the selection and design of
retainer
-correction of any supra erupted tooth
opposing pontic area is done prior to
construction of a bridge
f. Habits of patient
-bruxism patients should be given thicker
and stronger retainer than normal
because of their excessive clenching

2. Surface area of the casting
3.Periodontal condition
In Gingival recession –place margins supra
gingivally to minimize gingival irritation
5.Effective root surface area
6.degree of eruption of crown of the tooth

9. Condition of abutment teeth
Partial veneer crown-non-carious abutment
Endodontically treated tooth- post and core
Full veneer crown-large carious abutment
10. Preservation of tooth structure
Partial> fullveneer >all ceramic
11.Relation with the opposing tooth

12.Material used in the construction of the
retainer
13.Condition of root
Shape, periodontal condition and surface
area are considered
14.Alignment of tooth
15.Mutiple retainers
Placed by locking various retainers
together with precision attachments

1.EXTRACORONAL
A.FULLVENEER
CROWN
a. Complete metal
b. All ceramic
c. Metal ceramic
B.PARTIAL VENEER
CROWN
a. Anterior
-3/4crown
b. Posterior
-3/4 crown or 4/5 crown
-Reverse ¾ crown
-mesial1/2crown
-7/8crown
C.RESIN BONDED
RETAINERS
2.INTRACORONAL
a. inlays
b. onlays
3.RADICULAR
RETAINERS

FULL METAL CROWNFULL METAL CROWN
Introduced by
W.N.Morrison-1869
INDICATIONS
Extensive coronal
destruction
Short clinical crowns
Max retention and
resistance needed
Axial correction
needed
Endodontically
treated teeth

CONTRAINDICATIONCONTRAINDICATION
If treatment objective can be met with more
conservative preparation
High esthetic demand
When less than max retentive and resistance
needed

ADVANTAGESADVANTAGES
Highly retentive
High resistance
Superior strength
Axial contour modification
Occlusal modification

DISADVANTAGESDISADVANTAGES
1.more extensive preparation
2.not feasible for electrical vitality test
3.esthetic objection

PREPARATIONPREPARATION
Includes following steps
Occlusal guiding grooves
Occlusal reduction
Axial alignment grooves
Axial reduction
finishing

Guiding grooves
 round end tapered diamond
 Placed in the mesial, central, distal fossa-
appx 1mm depth
 Placed in buccal and lingual dev. Groove
• Purpose:
 occlusal reduction follows anatomic
configuration and minmizes loss of tooth
structure

Depth orientation grooves :round
end tapered
Half occlusal reduction done

Chamfer and axial finishing torpedo bur Seating groove no.171Lbur

METAL CERAMIC CROWNMETAL CERAMIC CROWN
Most widely used fixed restoration
Consists of
Cast metal crown + layer of fused
porcelain-mimics the natural tooth
Requires considerable tooth reduction-to
mask the metal sub-structure
Strength(metal)+esthetics(porcelain)

INDICATIONSINDICATIONS
High esthetic demand
FPD retainers and single restorations for
anterior and posterior teeth
Mandibular anterior teeth where full shoulder
is prohibited
 Peg shaped laterals/teeth with morphologic
deviations

CONTRA-INDICATIONSCONTRA-INDICATIONS
a. Active caries
b. Periodontally compromised teeth
c. Young patients
d. Where conservative treatment feasible

A. Strength & Esthetics
B. Excellent retentive qualities
C. Axial form correction
D. Occlusal correction

DIS-ADVANTAGESDIS-ADVANTAGES
1.High tooth reduction
2.Risk of periodontal disease-facial margin
placed subgingivally
3.Inferior esthetic-to all porcelain
4.Expensive
5.Subjectable to stress fracture
6.Difficulty in shade selection

Includes 5 steps
1.Guiding grooves
2.incisal reduction
3.labial reduction
4.Axial reduction of proximal and lingual
surfaces
5.finishing

Guiding grooves
Place 3grooves-
centre,mesiofacial,distofacial line angles-
parallel to long axis of the tooth-in 2 sets
One parallel to gingival half of labial
surface
Second parallel to incisal half of labial
surface
Approximately 1.4mm deep

Labial/buccal reduction
Cervical plane-path of placement of
restoration
Incisal plane-provides space needed for
porcelain veneer
Resulting shoulder-1mm wide with
0.5mm apical to crest of gingiva

Lingual reduction
 Lingual surface is reduced with
Small wheel diamond to obtain a
Minimum clearance of 0.7mm
With the opposing teeth
 Lingual surfaces that receive
ceramic veneer should have 1mm
Clearance
 Care should be taken so that the junction between
cingulum and lingual wall must not be overreduced

Axial reduction
 -Proximoaxial and linguoaxial surfaces-reduced
with torpedo diamond held llel to path of
withdrawal of restoration-with a taper of 6
degree
 -lingually chamfer is prepared with depth of
0.5mm width and extended buccally to blend
with interproximal shoulder

Lingual axial reduction : torpedo
diamondInitial proximal
reduction : long needle
diamond

Finishing
 Axial and lingual finishing-torpedo bur
 Axial and shoulder-radial fissure bur
Evaluation
 Margins should provide distinct resistance to
vertical displacement of explorer tip

Axial finishing: torpedo bur Axial and shoulder
finishing: radial fissure
bur

ALL CERAMIC CROWNALL CERAMIC CROWN
All ceramic crowns are the most
esthetically pleasing prosthodontic
restorations
Resembles natural tooth structure in terms
of color and translucency
Only drawback is highly susceptible fracture

High esthetic requirement
Considerable proximal caries
Incisal edge reasonably intact
Endodontically treated teeth with post
and cores
Favorable distribution of occlusal load.

CONTRAINDICATIONSCONTRAINDICATIONS
High caries index
Where treatment can be achieved by more
conservative restoration
Insufficient tooth structure to support to
porcelain
 Thin teeth facio-lingually
bruxism
where opposing tooth occluding in the
cervical third of the crown
short clinical crown

The complete ceramic restoration has
improved esthetics because of its
superior translucency
The restoration will have good tissue
response because of inert nature of
porcelain
The restoration is slightly more
conservative than metal ceramic in labial
surface due to lack of metal
reinforcement

DISADVANTAGESDISADVANTAGES
The complete ceramic restoration will
have reduced strength compared to
metal ceramic because of lack of metal
reinforcement
The tooth reduction is more
The restoration is susceptible for
fracture due to brittleness of the
porcelain.
Mostly restricted to anteriors.

Includes 5 steps
1.Guiding grooves
2.incisal reduction
3.Labial reduction
4.Axial reduction
5.finishing

Guiding grooves
Usually placed in two sets
Flat end tapered bur
One set parallel to incisal
Half of labial surface
Second set parallel to gingival
Half of labial surface
Approximately 1.4mm deep

Labial reductionLabial reduction

Proximal reduction and lingual reductionProximal reduction and lingual reduction
Lingual reduction: s mall wheel
diamond
Lingual axial reduction:
flat-endtapered

FinishingFinishing
Fine-grit diamond or carbide is used.
Preparation is made smooth and continuous with no
unsupported enamel and 90 degree cavosurface
margin.

PIN LEDGE PREPARATIONSPIN LEDGE PREPARATIONS
Occasionally used as single restoration-
only lingual surface is prepared
Used as retainer for fpd to splint
periodontally compromised teeth
One or more proximal surfaces included
in preparation design
Pins extend to depth of 2mm into dentin-
which provides retention and resistance

Pin ledge is very conservative preparation
Plaque control easy-short margin length
And supragingival margin

Undamaged ant teeth with low caries
index
On bulbous teeth unsuitable for ¾
crowns

CONTRAINDICATIONSCONTRAINDICATIONS
Poor oral hygiene
On non-vital teeth
In cases where alignment of teeth will
obstruct path of withdrawal of fpd

 esthetically pleasing
Min tooth preparation
Lin concavity of max ant teeth can be
modified with pin ledge restoration
DISADVANTAGE
Pinholes are difficult to place in teeth that
are thin labiolingually

MAXILLARY CENTRAL INCISORMAXILLARY CENTRAL INCISOR
PINLEDGEPINLEDGE
3 designs of pinledge
Conventional ledge involving lingual
surface of teeth
Ledge with proximal slice
Ledge with proximal groove
preferance depends on
tooth configuration
presence/absence of caries

Tooth with slight proximal convexity
prepared with proximal slice
Tooth with small carious lesion-proximal
groove

PINLEDGE WITH PROXIMAL SLICE AND
PROXIMAL REDUCTION
Prepare proximal slice –tapered diamond-llel to
path of withdrawal
 purpose is-to provide room for a fixed dental
prosthesis connector
Proximal reduction includes proximal contact
area-not to extend too far facially-alter outline
form of the tooth

Incisal and lingual reduction
Incisal bevel prepared with diamond
inclined slight lingually-extends on the
crest of incisal edge -remain in curvature
of incisal edge-to minimize display of
metal
lingual reduction –football/wheel
diamond-follows the lingual marginal
bridge

LEDGES AND INDENTATIONS
two ledges prepared on reduced Li surface on
incisal and cervical region
prepared with cylindrical bur
indentations in left and right side of incisal ledge and
in cervical ledge-to prevent pulp exposure
when pinholes are placed,indentations are just within
mesial and distal marginal ridges-1.5mm inside
external tooth contour

PINHOLE PREPARATION
Pilot channels- small round bur-with depth of
2mm
Enlarge and deepen pilot channels with carbide
bur when orientation and placement are
satisfactory
Bevel the junction between pinhole and
indentation with round bur-slightly longer than
diameter of pinhole

PATIAL VENEER CROWNPATIAL VENEER CROWN
An extra coronal metal restoration that
covers only a part of clinical crown
Also called as partial coverage
restoration
Types of partial veneer crown
1.Ant 3/4crown
2.Post3/4 crown
3.Reverse ¾ crown
4.Mesial1/2 crown
5.Post7/8 crown

Retainers for fpd where restoration of
occlusal surface required
Intact buccal surface
Sturdy clinical crowns

Contra-indicationContra-indication
Short clinical crown
As retainer for long span FPD
Anterior endodontic tooth
Extensively damaged teeth
Poor aligned teeth

AdvantagesAdvantages
Conservative tooth preparation
Accessibility
Less gingival involvement
Good/complete seating of prosthesis
Feasible to electrical vitality test

Dis-advantagesDis-advantages
Less retentive/resistant than full crown
Limited path of withdrawal
Requires dextrisity from operator
Cannot be used on nonvital tooth

ANTERIOR 3/4 CROWNANTERIOR 3/4 CROWN

Steps in preparationSteps in preparation
1. incisal reduction
2. Lingual reduction
3. Inter-proximal reduction
4. Proximal box or groove placement
5. incisal offset placement
6. Facial bevel
7. Finishing the preparation.

Incisal reductionIncisal reduction
Use a tapered, round-ended diamond.
Reduce the incisal edge 1mm at 45 degree angle
to the long axis of the tooth.

Lingual reductionLingual reduction
Use a football-shaped
diamond.
Reduce lingual surface leaving
a slight ridge running
incisogingivally along the
center of the lingual surface.
Clearance with the opposing
teeth should be atleast 0.7mm
to 1mm.

LINGUALGINGIVAL
REDUCTION
Using tapered, round-ended
diamond, make a chamfer
0.5mm deep at the cervical
finish line.
This is usually parallel to the
incisal two third of the labial
surface.

Interproximal reductionInterproximal reduction
Reduce the proximal surface by moving the bur
from lingual to the facial surface.
Position the bur so that the tip of the bur is
farther facial than the shank.

Facial line angles must remain intact to
produce esthetically acceptable results.
Establish a light chamfer on the proximal
surface, blending it with the lingual chamfer.
Break the contact with adjacent teeth.

Proximal groovesProximal grooves
Using 167 carbide bur, place the proximal
grooves parallel to the incisal two thirds of the
facial surface.
Grooves resist the lingual displacement.
Grooves are a minimum of 3mm long and
terminate 0.5mm of the gingival finish line.
The facial and lingual walls of the grooves have a
2 to 5 degree incisal divergence.

Incisal groove/offsetIncisal groove/offset
Using inverted cone
bur develop a 0.5 to
1mm groove
connecting the
proximal grooves.
The grooves should
be in dentine.
Groove is not placed
at the expense of the
incisal edge.

Facial bevelFacial bevel
Using a fine, flame-shaped bur, develop a
narrow bevel less than 0.5mm on the
labioincisal finish line at right angles to the
incisal two thirds of the facial surface.

Finishing the preparationFinishing the preparation
Using finishing bur, round the line angles to
ensure continuity of all finish lines.

Thank you
For more details please visit

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