Failures of FPD / cosmetic dentistry courses

FailuresFailures
ofof
Fixed Partial DenturesFixed Partial Dentures
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Introduction
Post insertion problems
Causes of failure
- Biological failures
- Mechanical failures
- Esthetic failures
ContentsContents

Removal of prosthesis
 planned Retreatment
Summary & conclusion
References

IntroductionIntroduction
Prosthodontist should be aware of both
gross & subtle indications of failure &
should have knowledge of its remedial
procedures
Changes in environment may necessitate
removal & remaking of a bridge.

No bridge nor the teeth approximating
or opposing it can carry a lifetime
guarantee

Bridges do fail even when they are technically
well fabricated, because foundations fail or has
the potentiality of failure

The 5 Major Problems in Fixed Prosthodontics
 Diagnosis and Treatment Planning
 Patient Management and Mouth Hygiene
 Preliminary Mouth Procedures
 Tooth Preparation and Case Fabrication
 Dentist – Laboratory interaction.

Diagnosis and treatment planningDiagnosis and treatment planning
Treatment expectations
Esthetics is prime consideration
Limitations

 Extrusion of tooth into the edentulous space
if not corrected leads to an irregular
occlusal plane and patients occlusal
function can be disturbed.
 Increase life expectancy with minimum cost.

Medical and dental historyMedical and dental history
Chronic medical problem that makes the
patient unable to sit in the dental chair for a
sufficient length of time to complete a
dental procedure is recorded.
Chronic osteogenic problems
Respiratory and circulatory problems

Psychologic patients can frustrate the
dentist.
Chronic drug abuse patients
Chronic alcohol abuse – unreliability of
the patient and physical deterioration of
hard and soft tissues of the oral cavity.

Pulpal involvement
Periodontal problems
Temporomandibular joint disorders

Intraoral records and radiographicIntraoral records and radiographic
examinationexamination
• Adequate bone support of abutment tooth
• Sufficient root length
• properly shaped roots
• Need of Endodontic treatment
• Need of restorations
• Unerupted tooth and root tips

Mounted diagnostic castsMounted diagnostic casts
Occlusal interferences
Extruded and tipped abutments
Possible path of insertion problems

Intraoral examinationIntraoral examination
Mobile abutment tooth
Sensitive tooth
Oral hygiene and periodontal evaluation
Shade of the tooth
Caries
Old restorations
Oral habits

Patient management and oral hygienePatient management and oral hygiene
Patient should be informed about the
treatment for the quoted fees.
Number of appointments should be
explained
Oral hygiene instructions given

Postcementation examination done routinely
Radiographs taken for any caries, periapical
/ periodontal disease
Soft tissue response
Occlusion
Marginal integrity of restorationwww.indiandentalacademy.com

Preliminary mouth proceduresPreliminary mouth procedures
 Soft tissue treatmentSoft tissue treatment
• Periodontal surgery
• Crown lengthening by eletrosurgery
• Edentulous ridge recontoured

 Hard tissue treatmentHard tissue treatment
• Prophylaxis
• Occlusal equilibration(lateral interferences and
prematurities)
• Reshaping of tooth (incisal edges
recontouring,extruded teeth reducing , reshaping
proximal contacts of adjacent tooth)

• Abutment tooth should be caries free.
• Endodontic treatment if needed should be
performed with Pins and Post and cores
• Extra time and expense involved reflects in the
quality and prognosis of the finished restoration.

Miscellaneous proceduresMiscellaneous procedures
• Diagnostic wax up to
preview the completed
case.
• Esthetics for the patient
• Functional/technical
problems to the dentist www.indiandentalacademy.com

Orthodontic repositioningOrthodontic repositioning
• Upright the abutment
• Improve esthetics
• Failure to use can compromise function
and esthetics in many cases.

 Pretreatment occlusal splints if the vertical
dimension is to be altered.
 Custom incisal guide table to copy exact anterior
guidance

 Vertical dimension maintainer
appliance/index to check occlusal
reduction if there are insufficient
occlusal stops to maintain
occlusal dimension during tooth
preparation.

Tooth preparation and case fabricationTooth preparation and case fabrication
Retainer selection
• Esthetics
• strength of the tooth and retainer
• Caries index
• Occlusion
• Pulp size
• Path of insertion
• Cost for the patient www.indiandentalacademy.com

 Abutment preparation
• Inadequate reduction - shortens the life
expectancy of the restoration
• Do not permit development of properly
shaped cusp inclines ,cusp tips and fossae.
• Bulky contours – periodontal healthwww.indiandentalacademy.com

 Inadequate facial reduction prevents shading of
veneers and pontics.
 Overbuilding – periodontal health
 Inadequate interproximal reduction encroaches on
embrasure spaces and effects esthetics and proper
cleaning.

 Excessive reduction
 Reduce retention and
stability of the
restoration
 Tooth weakened and
pulpal damage

 Long span bridges and pier abutment – difficulty
in path of insertion
 special attention to
 Tipped/malaligned abutments
 Preparation with grooves, boxes and pins
 Precision and semi precision attachments
 Preparations done on the master casts so that the
results are surveyed. www.indiandentalacademy.com

 Finish line should balance with
• Retention and resistance form(amount of axial
reduction)
• Patients oral hygiene
• Esthetics
• Periodontal health

 Vitality of pulp
• Insufficient water and air coolant
• Dull cutting instruments
• Heavy pressure(excess friction and heat)
• Irreversible pulpal damage.

Treatment restoration (temporary restoration)
 Over extension of the margins – irritate if gingiva
and soft tissue damage
 Under extension – pulpal irritation from
sensitivity,preparation margins get damaged.

 Improper cementation – irritation to the soft tissue
if excess cement is not removed.
 Improper occlusion – occlusal trauma -pulp
damage
 Improper proximal and occlusal contacts – teeth
shift – effect fit of final restoration.

Final impression procedures
 Marginal tissues should be displaced from the
prepared margin
 Tissue retraction with mechanical or
mechanochemical methods
 Tissue injury – hemorrhage recession periodontal
pocket –affect final restoration.

Impression distortion
• Removing before the final set
• Expired shelf life of the material
• improper mixing
• Voids
• Incomplete detail

Dies and working casts
• Improper pouring and sectioning of the dies
• Dies with voids – difficulty in making accurate wax
pattern and occluding the casting
• Trimmed and marked properly to avoid
over/under extension of margins
• Casts mounted accurately – reduce occlusal
adjustments.

Final restoration
 Casting accurate on cast but not on abutment
• Temporary cement on abutment
• Check for debris/bubbles on inside of casting
• over extended margins
• Excessive proximal contacts

Dentist – laboratory interaction
Dentist needs
 Any special instructions to be given
Laboratory needs
 Detailed written work authorization that
accurately describes the design,materials
 Working casts properly prepared
 Preparation properly tapered and adequately
reduced

Post insertion problemsPost insertion problems

Thermal sensitivity
 Results from removal of enamel and dentin which
has insulating properties and their replacement
with metals which are excellent thermal
conductors
 Thermal diffusion through a substance is related to
its thermal conductivity and its thickness.
 Magnitude and duration increases if preparation is
close to the pulp.

 Failure to use water spray during reduction
increases the potential to post insertion sensitivity.
 Failure of temporary restoration to cover all
prepared tooth surfaces
 Loose temporary restoration that allows seepage of
oral fluids over prepared surfaces
 Temporary restoration that places excessive
occlusal forces on the prepared tooth.

Prolonged sensitivity that does not
decrease in severity with time/acute pain
indicates Endodontic treatment.

Discomfort during function
 Premature centric occlusal contacts/excessive
contact during eccentric mandibular movements.
 Occlusal adjustments relieves pain.
 Tenderness to percussion is also due to heavy
centric/eccentric occlusal contact.
 occlusal discrepancies that are not corrected lead
to Endodontic treatment.

 Tooth that have been out of occlusal function
for a long time initially exhibit discomfort
during function when the prosthesis is placed
but adjusts with time to the increased
functional activity.

Gingival inflammation
 May be caused due to the
clinical procedure carried out
 decreases if patient maintains
good oral hygiene

Inflammation due to clinical procedure is
 Soft tissue removal with rotary instruments
 Excessive tissue retraction
 Rough/poorly fitting temporary restorations
 Failure to completely remove remnants of
impression material or temporary cement
from the gingival sulcus

Inflammation after cementation
Faculty cervical contour, marginal fit, or
embrasure form of the prosthesis
 poor oral hygiene.

Retention of food
 Between abutment and adjacent teeth is due to
poor occlusal relationship or lack of adequate
proximal contact.
 Cusp from opposing dentition can occlude with
adjacent marginal ridge such that it forces the
teeth apart and wedges food interproximally.
 Offending cusp should be recontoured to reduce
wedging effect

 Missing/poorly located proximal contact causes
food impaction
 Properly constructed proximal contact can open
up due to heavy occlusal contact causing tooth
movement in response to the interferences
 Lack of occlusal contact allow eruption of tooth
with resulting loss of contact.

Trauma to the Cheek or Tongue
 Contact with sharp/poorly polished portions of a
prosthesis
 Cusp to cusp or end to end occlusal relationship
without normal horizontal overlap
 Horizontal overlap prevents soft tissue from being
caught between the occlusal surfaces .
 If the occlusion is unavoidable cusps should be
blunt

Failure of the final prosthesis to completely
cover all areas of the prepared tooth
surfaces
Significant portion of the luting agent has
undergone dissolution
Abutment retainer is loose – new FPD
fabricated
Caries on abutment/adjacent tooth.
Sensitivity to sweets

Tooth mobility
 Poor occlusal relationship that produces heavy
centric occlusal contacts or eccentric occlusal
interferences
 Overloading of prosthesis causes change in
periodontal ligament and supporting bone.
 Occlusal adjustments should be done

Inadequate osseous support - tooth
mobility in absence of excessive forces
 RPD provides bilateral bracing for
weakened tooth .

Neuromuscular discomfort
 Serious problem
 Pain in temporomandibular joint or associated
muscles is related to improper occlusion created by
fixed prosthesis
 Caused by premature contact.
 To avoid interfering and bring other teeth into
occlusion contacts muscular contraction guides the
mandible to a different position.

 New mandibular position can create
neuromuscular pain as a result of positional
changes in the ligaments and muscles
associated with the temporomandibular joint.

Nonspecific complaints
Patient aware of the prosthesis being in
place and feels slight discomfort.
Due to additional forces to the abutment
teeth,occlusal discrepancy or presence of
artificial tooth occupying a previously open
area.

• Complains due to –the patient does not like the
prosthesis but reluctant to discuss
• Financial aspects produces nonspecific
complaints.

Causes of failure
Biological failures
 Mechanical failures
 Esthetic failures

Biological failure

CariesCaries
 Most common
 probing of margins
of the prosthesis and
tooth surfaces .
 Radiographs helps to
detect caries
interproximally

Conventional operative treatment can
restore small carious lesions without the
need to fabricate a new prosthesis.
Gold foil/amalgam restoration of choice
for marginal caries.
Glass ionomer/composites in esthetics.

Caries in proximal surfaces require removal
of the prosthesis to obtain access
Lesion is small tooth preparation can be
extended to eliminate caries and a new
prosthesis is fabricates
If lesion is large an amalgam restoration is
required after removal of the restoration
and a new restoration fabricated

 Extensive lesions – Endodontic treatment
extraction
 High caries index patient – oral hygiene,
fluoride containing dentifrices, topical fluoride
application

 Sensitivity that does not subside with
time,intense pain, periapical abnormalities
need Endodontic treatment
 Access to the pulp requires preparation of a
hole in prosthesis through which treatment is
done.
Pulp degeneration

 Perforation can be
restored with gold foil,
amalgam or a cast metal
inlay .

 Casting may become loose during the access
opening or porcelain may fracture-remake.
 If little sound tooth structure remains after
Endodontic treatment a post and core is placed
and new restoration is fabricated.

Periodontal breakdown
 Poor marginal adaptation
 Over contouring of the axial
surfaces of the retainers
 Large connectors that restrict
the cervical embrasure space
 Large pontic
 Prosthesis with rough
surfaces should be
recontoured/remade

 Extensive bone loss – loss of
abutment teeth and attached
prosthesis.
 Less severe breakdown is treated
with surgery which lead to
unacceptable relationship between
the prosthesis and the soft tissue.

If abutment is lost the retainer casting
can be filled with amalgam or composite
and formed in the shape of pontic

Occlusal problems
 Interfering centric/eccentric occlusal contacts -
tooth mobility
 Detected early – occlusal adjustments – prevent
permanent damage.
 Long term presence of occlusal interferences can
lead to severe mobility ,teeth should be bilaterally
braced with removable partial denture.

Excessive mobility and reduced bone
support – extraction of abutment teeth.
Interfering contacts – irreversible
pulpal damage – Endodontic treatment.

Neuromuscular discomfort due to improper
occlusion can result in prosthesis failure, as
occlusal adjustments that are required to
allow the mandible to be properly positioned
may cause perforation of the prosthesis or
make the restoration esthetically
unacceptable.

Tooth perforation
 Pin/pinholes used in pin retained restorations can
be improperly located and perforate the tooth
laterally.
 If located occlusal to the periodontal ligament
-extend the tooth preparation to cover the defect
 Into the periodontal ligament – periodontal
surgery and to smooth off the projecting pin .place
a restoration into the perforated area

 Perforations into the furcations – inaccessible for
restoration – extraction
 Lateral perforations can occur during Endodontic
treatment / post and core preparation.

 If accessible can be
restored with amalgam
but more often the
tooth is lost.
 If pins perforate pulp
chamber – Endodontic
treatment

Mechanical failures

Loss of retention
Patient is aware of looseness
Sensitivity to temperature or sweets
Bad taste/odor

Periodic recall include unseating existing
prosthesis
Loose casting – fluids drawn under the
casting, when reseated with a cervical
force fluid is expressed producing
bubbles as air and liquid are
simultaneously displaced.

If restoration dislodged without damage and
no caries - recementation of the restoration.
Recent cement failure of one abutment with
no caries – clean with hydrogen peroxide
/sodium hypo chloride solution, inject
cement/low viscosity composite through an
access opening made in the lingual.occlusal
surface.

 Fill the retainer until excess appears on all the
gingival margins. allow the cement to set under
biting force.
 Prosthesis removal reveals lack of adequate
retention by the preparation form, teeth should be
modified to improve resistance and retention form,
and a new prosthesis should be fabricated.

Connector failure
 Can fracture under occlusal forces
 Placement ,size and shape and finishing errors
 Placed in contact area
 Size and shape depends on length of the span,area
of the arch.
 Vertical dimension has more effect on strength
than horizontal dimension

Short span – well shaped and less bulky
connectors.
Both cast and soldered connections fracture
– internal porosity that weakened the metal.
 Pontics are placed in a cantilever
relationship with the retainer - excessive
forces to the abutment tooth.

Difficult to detect clinically
Wedges are positioned to separate
individual components to conform the
correct diagnosis

Prosthesis should be removed and
remade
Removable partial denture is inserted to
maintain the existing space and esthetics.

Occlusal wear
 Heavy chewing
forces,clenching/bruxism –
accelerated wear
 Casting perforation develops
as occlusal metal thickness is
limited by tooth reduction
 Detected early –
gold/amalgam restoration

Occlusal surface is ceramic– wear of natural
tooth,metallic restoration
Occlusal surface metal – integrity of
opposing tooth is maintained.

Tooth fracture
Excessive tooth preparation( cannot resist
occlusal forces)
Preparation mostly of restorative material
which was not retained in sound dentin with
pins.
Interfering centric/eccentric contacts

Heavy occlusal forces
Forcibly seating an improperly fitting
prosthesis
Unseat a cemented bridge incorrectly.

 New prosthesis that
encompasses the fractured area
if the fracture is coronally
limited.
 Fracture – pulp exposure –
Endodontic treatment with post
and core.

Root fractures are caused by
• trauma
• Endodontic treatment
• Forceful seating of a post and core
• Seating an improperly fitting post and core.

Root fracture below alveolar bone crest
– extraction.
Fracture ends just below the alveolar
bone – periodontal surgery,expose
fracture site to be encompassed by a new
prosthesis

Acrylic veneer wear
 Functional loading,abrasive
foods/tooth brush abrasion
 Repair – autopolymerising resin
with mechanical retention
(undercuts/threaded posts)
 Composites – more popular.
mechanical more resistant to
wear and maintain function and
appearance longer than acrylic
resin.

Porcelain fracture
Metal ceramic –
improper design of metal frame work /
problems related to occlusion
All ceramic –
deficiencies in tooth preparation /
heavy occlusal contacts.

Laboratory related
dentist related
 patient related

Metal ceramic
Frame work design
• Sharp angles/rough/irregular areas over the
veneering areas – stress concentration-crack
propagation and ceramic fracture

Porcelain fracture – framework design
that allows centric occlusal contact on /
immediately next to metal ceramic
junction

 Major difference in thickness of
porcelain from one area to another.
• Porcelain thickness is increased on
pontics, If proper tooth shaped
metal framework is not developed
 Internal strains develop and
fractures occur under little/no load.

Occlusion
 Clenching and bruxism
 Night guard
 Centric/eccentric occlusal interferences
 Trauma/accidents/foreign objects in food.

Metal handling procedures
Improper handling of alloy during casting
– metal contamination (separation of metal
and porcelain in severe contamination)
Bubbles form at metal-ceramic junction -
creating stress and cracks

Preparation,impression and insertion
 Thin metal casting doesn't support porcelain –
porcelain fracture.
 Framework thickness of less than 0.2 mm over
veneering surface - high failure rate.
 Tooth preparation with slight undercut - binding
of the prosthesis as it is seated – initiates crack in
porcelain.

Distorted impression – improper fit of
the prostheses and crack propagation
Feather edge finish line/impression that
does not record the finish line ,extension
of metal beyond the finish line .Thin
metal bind against the tooth and initiate
a crack in overlying porcelain

Repair of fractured metal ceramic
restorations
 Best method – new
prosthesis
 Composites – lack of
longevity.
 Mechanical retention
gained from undercut
metal substructure.
 Color changes that
makes repair obvious.

If adequate metal thickness is available
Removal of remaining porcelain on the
fractured unit to expose the underlying
metal
Drilling several pinholes(4-5) into the
framework to a depth of at least 2mm and
making of an impression

 Creating a pin retained metal casting 0.2 – 0.3 mm
thick of metal ceramic alloy to fit over the exposed
framework
 Fusion of porcelain to pin retained casting
 Cementation of casting
 With adequate pin length – lasts longer
 Recemented - if becomes loose

All Ceramic Crowns
Anterior – no failures
Posteriors – fractures because of occlusal
load
Advanced materials – crowns on
posteriors

Vertical fracture
• Tapered finish line (chamfer),restoration contacts
the tooth on a sloping surface,forces are produced
that tend to expand the restoration and not well
resisted by porcelain.
• Sharp line angles/incisal edges - stress
concentration.

when large portion of the proximal
preparation form is missing and not
restored prior to impression,
Occlusal forces when applied to the
marginal ridge in which the missing tooth
form is located, occlusal forces tend to rotate
the restoration causing expansive forces

Rounded preparation without retention and
resistance form tends to rotate the
restoration and lead to fracture of the
restoration.

Lingual fracture
Semilunar lingual fracture – occlusion
cervical to the cingulum of the
preparation,forces to the porcelain are more
shear in nature and not well resisted

 Inadequate lingual tooth
reduction (less than 1 mm of
porcelain present)
 Heavy occlusal forces.

Repairs
New restoration
Heavy occlusal forces – metal ceramic
restoration

Esthetic failures

Actual failure
• Color mismatch
• Poor tooth contour
• Poor gingival contour/color
• Poor margin placement
• Poor residual pontic ridge
contour
• Unrealistic expectations by the
patient
At the time of cementation

Delayed esthetic failure
Gingival recession
• Prominent roots
• Poorly fitting crowns
• Excessive trauma during
preparation and
impression making

 Subpontic tissue shrinkage
 Periodontal surgery
 Porosity – poorly glazed
porcelain appear satisfactory
at cementation but later
develops black specks

Drifting of anterior teeth- loss of periodontal
support
loss of posterior occlusal vertical dimension
loss of circumoral elasticity.
Wear – lower anteriors when opposed by
porcelain.

Incorrect form /framework design that
display metal
Natural teeth undergo color changes(over
years)
Outline form is not contoured
Preparation of thin incisors - metallic color
visible with time.

Subpontic
inflammation
• Pain
• Swelling
• Bad breath
• Bad taste
• Bleeding gums
• Poor esthetics.

SUBPONTIC DEFECTS
 Defect in subpontic area - esthetic problems
 Seibert in 1983 classified ridge defects as
 Class I – facio-lingual loss of tissue with normal
ridge height in an apico-coronal direction
 Class II – apico-coronal loss of tissue with normal
width in facio-lingual direction
 Class III – combined facio-lingual and apico-
coronal loss of tissue ,resulting in loss of normal
height and width. www.indiandentalacademy.com

Perio surgery with grafts
Eletrosurgery
Prosthetic gingiva with removable
prosthesis

removal of a prosthesis
 Intact restorations must be cut off
to prevent abutment tooth
damage.
 Applying a sharp force in an
occlusal direction with a chisel
and mallet to tap on the retainer
and induce dislodgement
 Chisel should be placed parallel to
the path of withdrawal.

 CORONAFLEX crown remover
 Air driven device that connects to standard
handpiece hoses via Kavo’s Multiflex coupler
 The crown remover delivers a controlled low
amplitude impact at its tip
 Kit includes loop to thread under FPD’S
connectors that is attached to a holder,calipers,and
an adhesive clamp to obtain a purchase on single
crowns

It delivers the impact in the long axis of the
tooth
The loop is threaded under the connector.
The tip of the crown remover is placed on
the bar and the impact is activated by
releasing the index finger from the air valve
The adhesive clamp is attached with
autopolymerising resin used to remove a
single crown. www.indiandentalacademy.com

 METALIFT crown and bridge
removal system
 Access to the metal on each
abutment is provided by
preparing through the
porcelain around bur to create
a pilot channel in each
abutment
 The pilot hole is followed by
the special drill.

 Cement should be visible
through the hole
 The metalift instrument
is threaded into the holes
and the FPD removed.
 It can de Recemented for
further service.

 Roydent bridge and
crown remover
 Designed to grip a
crown/FPD and to
deliver a removal
force along the long
axis.

RICHWIL crown and bridge remover
Small cubes of Adhesive water pliable resin.
softened in warm water(55 degrees) for 1-2
minutes and patient is instructed to occlude
on it.
The resin is cooled with water
A sharp opening action will remove the
crown

Removing partially uncemented crowns
Retainers which have been sectioned.
But still resists removal

HIGA bridge remover
 Removal of provisional
bridges/cementation
failures
 A cavity is cut into the
occlusal surfaces of
crowns to expose the
tooth.
 The pins on the remover
are adjusted to align
with the cavities www.indiandentalacademy.com

 0.5 mm of wire is passed beneath the proximal
joints and extends out of the mouth
 The wire is attached to the spindle and tightened
by turning the screwdriver
 Further tightening applies axial load on the tooth
via the pins and an occlusal load on the bridge via
the wire,and cement fracture fracture occurs.

A thin slot from the finish line to the occlusal
surface is cut through the restoration
(tapered/round bur)
Lingual – anteriors (esthetics)
Facial – posteriors(difficult access)
Can be used as temporary restorations
Porcelain restorations fracture – remake
needed. www.indiandentalacademy.com

 Thin bladed instrument is
placed into the slot and
twisted to expand the
circumference of the retainer
and dislodge it.

Planned Retreatment
Retreatment should be considered because
of difficulties in accurately predicting the
pattern of future dental disease.
Survey contours are incorporated in the
retainers of an fixed partial dentures to
accommodate a future removal partial
denture in the event of terminal abutment
loss .

Accommodation made for future occlusal
rest by increasing occlusal reduction during
tooth preparation and using occlusal
surfaces
Proximal boxes can be incorporated if a
nonrigid rest could simplify future
Retreatment .

Retained roots
 Provide support for the
implants
 Maintain alveolar bone
Sleeping implants
 Osseo integrated implants are
placed at the time of Perio
surgery and exposed later can
save 3-6 months of treatment at
a later stage. www.indiandentalacademy.com

Occlusal stabilization appliance
Powerful masticatory musculature
Bruxism
Worn to reduce porcelain fracture.
Presence of crowns with short posts or
grossly different mobility between
abutments

Copings
 Provisional subcopings
 Open top Provisional
subcopings
 Definitive subcopings.
 Allow future modification
 Permit cementation failure.

 Long spans bridges
 short clinical crowns
cannot increase the clinical crown height
by surgery
• Can lead to exposure of furcations
• Presence of high external oblique ridge
• Medically compromised patients
• Refuses surgery
 Cement the bridge with temporary
cement over copings www.indiandentalacademy.com

Coping to pier abutment if mobility is
different than the end abutments.
Intracoronal attachment should be
incorporated into the distal surface of the
tooth anterior to the suspect tooth

Tooth loss and replacement with RPD
Incorporate into the anterior pontic-
Intracoronal attachment
Lingual arm- a lingual recess is milled into
the pontic so that a lingual arm can be
incorporated on the most distal retainer
This provides lateral stability to the joint and
prevents premature wear of the internal
attachment when the abutment tooth has little
periodontal support www.indiandentalacademy.com

Guide planes
On the distal and lingual surfaces
Buccal undercut
Mesiobuccal/distobuccal for engagement of the
clasp

Review of literature
1. Charles J.Goodacre - a study was done to identify
the incidence of complications and the most common
complications associated with single crowns,fixed
partial dentures,all ceramic crowns,resin bonded
prosthesis and post and cores.

The lowest incidence of clinical
complications was associated with all-ceramic
crowns(8%).post and cores(10%) and
conventional single crowns (11%),resin
bonded prosthesis(26%) and conventional
FPD’s(27%).

3 common complications with all ceramic
crowns were
Crown fracture(7%)
Loss of retention (2%)
Need of Endodontic treatment (1%)

 3 common complications with post and core were
 Post loosening(5%)
 Root fracture(3%)
 Caries (2%)

 Common complications with single crowns
 Need of Endodontic treatment ( 3%)
 Porcelain veneer fracture(3%)
 Loss of retention (2%)

 Common complications with conventional FPD’s
 Caries(18%)
 Need of Endodontic treatment (11%)
 Loss of retention ( 7%)

 Common complications with resin bonded
bridges
 debonding(21%)
 Tooth discoloration(18%)
 Caries (7%)s
(JPD 2003;90:31-41)

2.J.E Reuter – long span bridges and bridges
involving anterior or posterior retainers were
more likely to fail than short span bridges.
Abutments that were root treated after bridge
cementation were more prone to retainer or
abutment fracture than vital abutments or those
root treated before hand.(Br Dent J
1984;157:61)

3.Greg Libby - the anticipated length of service
and reasons for replacement of fixed partial
dentures were evaluated.he concluded that
dental caries was the most frequent cause of
failure(38%),followed by periapical
involvements(15%), perforated occlusal
surfaces(15%),fractured post and core
(8%),defective margins (8%)fractured teeth
(8%),porcelain failures (8%).www.indiandentalacademy.com

The mean length of service for failed FPD’s
ranged from 16 years,because of caries to 4.1
years,because of fractured post and core.
The length of service of a FPD is not
dependent on the number of years in service,
but the use of specific procedures and routine
recall appointments can increase the length of
service of these restorations. (JPD
1997;78:127-31). www.indiandentalacademy.com

4.Won-Suck Oh , conducted a study to test that
the radii of curvature at the connector affects
the fracture resistance of 3-unit FPD’s.he
concluded that fracture resistance was affected
by modification of the radius of curvature
within the embrasure space. radius of curvature
at the gingival embrasure strongly affected the
fracture resistance of all ceramic FPD’s.

As the radius at the gingival embrasure
increased from 0.25 – 0.90mm,the mean failure
load increased by 140%.
Results of this study suggest that the occlusal
embrasure can be designed as sharp as is
practicable for esthetics , provided that the
gingival embrasure has a greater radius of
curvature.(JPD 2002 ; 87:536-42).

Summary
Treatment does not end with the fitting of
restorations. Subsequent maintenance is an
integral part of treatment. If this is not
adequately prescribed, failure can occur.
Well organized & efficient post operative
care is the chief mechanism for successful
Fixed Prosthodontics

references
 Rosenstiel ,Contemporary fixed Prosthodontics,3rd
edition,2001.Mosby publishers
 Michael D Wise. Failure in Restored dentition:
Management and treatment. 1996. Quintessence
Jhonston’s Modern practice in fixed
Prosthodontics. 4th
pub.
 Dykema . edition.1986.
 Thayer

 Charles J.Goodacre - clinical complications in fixed
Prosthodontics,JPD 2003;90:31-41.
 .J.E Reuter – failures in full crown retained dental
bridges.Br Dent J 1984;157:61.
 Greg Libby – longevity of fixed partial dentures, JPD
1997;78:127-31.

 won-suck oh – effect of connector design on the
fracture resistance of all ceramic fixed partial
dentures,JPD 2002;87:536-42.
 Mirza F.D – failures in crown and bridge
Prosthodontics,Journal Indian association.52;381-383.
 W.R.Teteruck -Failures in fixed Prosthodontics –
faculty of dentistry,University of Western
Ontario,division of fixed Prosthodontics,department
of restorative dentistry.

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