When a crown or Fixed Partial Dentures (FPD) fails, the primary question is whether the problem can be easily resolved, or requires extensive rehabilitation and reconstruction.

1. Restorative Department
2020

2. • A failure has been defined as the state or condition of not
meeting a desirable or intended objective, and may be viewed
as the opposite of success. Fixed prosthodontic failures can be
complex in terms of both diagnosis and treatment.
INTRODUCTION
• Replacement of missing teeth in partially edentulous arch
involves various treatment options like removable, fixed
prosthesis, and implants. Fixed prosthodontic treatment can
offer exceptional satisfaction for both patient and dentist

3. • Restoring and replacing of teeth with FPDs represents an
important treatment procedure in dental practice, mainly
because of the continuing high prevalence of caries and
periodontal diseases in the adult and geriatric populations.
• When a crown or Fixed Partial Dentures (FPD) fails, the
primary question is whether the problem can be easily
resolved, or requires extensive rehabilitation and
reconstruction. A mild failure may be considered one that is
generally correctable without having to remake the restoration.

5. • As a matter of fact, the objectives of fixed prosthodontic
treatment include: the preservation or the improvement of
tissue structure, oral functions, and esthetics, ensuring
restoration retention, resistance, and stability, and improving
patient comfort for maximum longevity.
• Failure to achieve the desired specifications of design for
function and esthetics would fail the prosthesis.

6. • Most of the time, the failures are conditions that occur during
or after performed fixed prosthodontics treatment
procedures.
• Failure of the fixed prosthesis can occur in many ways. The
reasons for failure may be divided into biological failures,
mechanical failures, and esthetic failures.
• Mechanical failures are more directly under the influence of
the clinician.

8. • Biological problems are less easily controlled and in some
instances may be unrelated to the treatment or prosthesis.
• Fixed prosthodontic failures are varied and include secondary
caries, endodontic complications, ditching of the cement
margin, unacceptable esthetics, cracking, and chipping
fracture.

9. • In case of large destruction of coronal tooth structure and
after endodontic therapy, the reconstruction of structurally
compromised non vital teeth seems to be necessary.
• Burke, et al. reported in a retrospective study that there were
36% of the re-intervention involving recementing, 17%
replacement of crowns, 13% direct restorations, and 12% root
treatment.

10. • In fact, selecting the appropriate reconstruction for each non
vital tooth should be based on many factors such as the
remaining hard tooth structure, the number and thickness of
the residual cavity, the position of the tooth in the arch and the
load implied.
• The clinical choice may be an esthetic post and core
restoration consisting of a composite resin core retained by a
fiber post which has better stress distribution pattern and
esthetic result.

11. 1. Looseness of the FDP
2. Rocking on chewing & during function
3. Continued Ingress of food and saliva
4. Caries under the FDP
5. Increased Gingival inflammation under the
pontic/retainer
6. Progressive Gingival recession
SIGNS AND SYMPTOMS OF FAILURES IN
FDP:

13. 8. Periapical inflammation of abutment
9. Food impaction
10.Tooth mobility
11.Fracture or loss of facing
12.Discoloration
13.Perforation of metal frame
14.Pain on percussion or Sensitivity of abutment
15.Outright fracture of FDP
16.Supra eruption / mesial drifting of adjacent teeth

15. The causes of FPD failures were summarized as early as in 1920
when Tinker wrote “ Chief among the causes for such disappointing
results have been:
First: Faulty, and in some cases, no attempt at diagnosis and prognosis.
Second: Failure to remove foci of infection in attention to treatment and
care of the investing tissues and mouth sanitation.
Third: Disregard for tooth form.
Fourth: Absence of proper embrasures.
Fifth: Inter-proximal spaces.
Sixth: Faulty occlusion and articulation.

16. Factors Causing Failure Of Crowns And Bridges
Could Be Classified According To The Stage In
Which It Occurs As Follows:
1. Before Preparation.
2. During preparation.
3. During construction.
4. During cementation.
5. After Cementation.

17. 1) John. F. Johnston classification – 1986
according to mechanism of failure:
1) Biologic Failure
2) Mechanical Failure
3) Aesthetic Failure.
4) Maintenance Failure.

18. This prep featured adequate height, and minimally
tapered walls. Although there were no slots or
grooves, the prep design was deemed to be retentive
enough for RMGI cement.

19. Discomfort or Pain
Caries
Pulp Injury
Periodontal
breakdown
Occlusal problems
Tooth Perforation
Tooth fracture

20. Discomfort or Pain
 Excessive Pressure on soft tissues:
1. Improper pontic/ ridge relationship.
2. Foreign body pressing on the ridge.
3. Over extension cervical margins of retainers or crowns.
4. Faulty proximal contact.
5. Improper labial or lingual contour of retainers or
pontics.

21. The gingival crest is not
positioned as far apically
on the restored central
incisor, and its form is
rounded and thick rather
than the normal form of
the gingival margin, which
is thinner and sharper.
Accelerated gingival
recession around maxillary
left central incisor resulting
from metal-ceramic crown
with subgingival margins
placed at a young age. The
gingiva is edematous and red,
and the gingival margin is
rounded and thick.

22. Retention of food on the occlusal surface:
1. Lack of auxiliary escape grooves.
2. Improper buccal and lingual embrasures.
Food Impaction & Improper Embrasures

23. Traumatic occlusion:
• Premature contact
 Torque
1. Lack of parallism.
2. Absence of temporary protection.

24.  Cervical hypersensitivity of the abutment:
1. Over displacement of gingival tissue during impression
taking
2. Over extended cervical margins of restoration
3. Short or open cervical margins of restoration
4. Over extended temporary protection
5. Cervical caries

26. Caries
Due To:
1. Open Margins.
2. Short Margins.
3. Over Extended Margins.
4. Incomplete Removal Of Caries During Previous
Treatment.
5. Use Of Wrong Type Of Restoration Which Promote
Caries Development.
6. Poor Oral Hygiene.

28. Pulp Injury
Due To;
1. Improper use of coolant.
2. Over reduction leaving insufficient dentin protective barrier.
3. Minute pulp exposure.
4. Improper or absence of temporary protection.
5. Use of irritating luting agent.
6. Recurrent caries under the restoration.
7. Low grade pulp irritation as a results of traumatic occlusion.

29. Over reduction
Pulp Exposure

30. Periodontal breakdown may lead to loss of abutment.
 Patient suffer from;
 Mobility of abutment.
 Periodontal pocket formation.
 Periodontal abscess.
 Pain which prevent mastication at the side of restoration.
 Bad odor and taste.
Periodontal Breakdown

31. Periodontal breakdown may be due to;
1. Inadequate abutment teeth in long span bridge.
2. Periodontally affected abutment teeth.
3. Patient with poor oral hygiene.
4. Poor marginal adaptation.
5. Over or under contour of axial walls
6. Extensively large connectors that restrict the cervical embrasure.
7. Pontic with large contact area on edentulous ridge.
8. Improper or absence of proximal contact causing food impaction
and periodontal pocket formation.
9. Irregular or rough cervical margin of prosthesis.

32. Periodontally
affected abutment
teeth
Inadequate abutment teeth in
long span bridge

33. Premature
Contact In
Centric And
Eccentric
Occlusion
Excessive Tooth
Mobility
Cause

34. Tooth Perforation
Due To;
1. Faulty preparation during pinhole preparation.
2. Faulty during post space preparation.

35. Tooth fracture
1. Over reduction of abutment.
2. Recurrent caries.
3. Un-retained restoration.
4. Presence of premature contact force.
5. Application of excessive force during seating of improperly
fitting restoration.
6. Incorrect removal of cemented restoration.
1- Coronal tooth fracture Due to;

36. 1. Excessive widening of root canal
during endodontic treatment or
during post space preparation.
2. Forceful seating of post.
3. Caries extended to root surface 4.
Trauma.
2- Root fracture Due to;

37. 1. Cementation failure;
looseness and/or dislodgment of restoration, it could be due to
a- Cement failure
b- Retention failure
c- Occlusal problems
d- Different degree of abutments mobility
2. Restoration failure ( retainer, pontic, or connector )
3. Occlusal wear or perforation

38.  Cementation Failure:
a- Cement failure: This could be due to;
1- Cement selection
2- Expired cement
3- Clinician not follow manufacturer’s instructions
4- Incomplete removal of temporary cement
5- Inadequate isolation
6- Inclusion of cotton fibers
7- Incomplete isolation
8- Insufficient pressure seating

39. Cementation Failure:
b- Retention failure This could be due to;
1- Excessive taper
2- Short clinical crown
3- Misfit
4- Misalignment

40. c- Occlusal problems This could be due to;
1- Occlusal Interference
2- Occlusal Perforation
3- Parafunctional Activity
4- Loss Of Occlusal Contacts
d- Different degree of abutments mobility; This induce
stresses on the cement which lead to cementation failure.
 Cementation Failure

42. 1- Pull the restoration margin and see for movement of
it.
2- Bubbles come out of the margin or perforation (if
present) when the restoration pushed by occlusal
pressure

43. a- Retainer failure;
• Perforation
• Marginal discrepancy
• Veneering separation
• fracture or wearing
b- Pontic failure;
• Pontic fracture (Porcelain) with unfavorable occlusal load.
• Limited occlusocervical height due to over eruption.
 Restoration Failure:

44. c- Connector failure;
This could be due to;
1- Improper designing of connector size and position
2- Thin metal at the connector
3- Incorrect selection of solder
4- Porosity

45.  Aesthetic Failure:
• Improper shade matching .
• Insufficient tooth reduction .
• Disharmony between restoration and neighboring teeth .
• Improper masking of metal by esthetic material.
• Use of improper shade of cement with all ceramic restoration .
• Unnecessary display of metal in case of partial veneer metal
restoration .
• Improper marginal adaptation, form, roughness, or extension
which lead to gingival inflammation causing unnatural soft tissue
color.

47.  Maintenance Failure:
Poor oral hygiene and improper maintenance of a well done
restoration may lead to failure of prosthesis.
The patient must be fully informed about his responsibility in
success or failure of restoration.
The dentist must recall the patient for periodic clinical and
radiographic examination to detect early any harmful
changes that might occur.

49. 2) Smith classification – 1985:
1. Loss of retention
2. Mechanical failures of crown and bridge components
3. Changes on abutment tooth
4. Design failures
5. Inadequate clinical or laboratory technique
 Marginal deficiencies
 Defects
 Poor shape and color
6. Occlusal problems.

50. 3) Wise classification – 1999:
1. General pathosis.
2. Periodontal problems.
3. Caries.
4. Pulpal changes.
5. Erosion.
6. Cracked teeth.
7. Subpontic inflammation.
8. Temporomandibular joint disorders.
9. Occlusal problems.

51. 4) Selby Classification – 1984:
Biologic
1. Caries
2. Periodontal disease
3. Endodontic or periapical problems.

52. Mechanical
1. Loss of retention
2. Fracture or loss of porcelain
3. Wear or loss of acrylic veneer
4. Wear or perforation of gold
5. Fracture of metal framework
6. Fracture of solder joints
7. Fracture of abutment tooth or root
8. Defective margins
9. Poor contour
10. Poor esthetics.

53. • Single Crown Complications Duration-1 to 23 years. (studies)
Incidence of complications 11%
• FDP complications Duration-1 to 20 years. (studies) Incidence
of complications 27 %
• All Ceramic Complications Duration-1 month to 14 years.
(studies) Incidence of complications 8 %
• Resin Bonded prosthesis Complications Duration-1 month to
15 years. (studies) Incidence of complications 26 %
Charles etal1 Described the Incidence of Failures
in His Article