Failures in fixed prosthodontics
Causes of fixed prosthesis failures:
1) Improper case selection
2) Faulty diagnosis and treatment planning
3) Faulty clinical or laboratory procedures
4) Improper care and maintenance
Classification of fixed prosthesis failures:
I) Biological failures
II) Mechanical failures
III) Esthetic failures
IV) Maintenance failures
I) BIOLOGICAL FAILURES:
1) CARIES:
Represent 36 % of biological failures
Can occur at :
a) Margin:
Causes open/ short / ill-fitted margin
Detected by sharp explorer
1
,b) Beneath restoration:
Causes incomplete caries removal
loose retainers microleakage.
Caries susceptibility under fixed partial denture is more than
under single crowns
c) Root:
Causes decrease salivary secretion especially in old aged
patient.
Commonly associated with gingival recession and
periodontal pockets.
Signs and symptoms;
i) Bad taste and breath
ii) Loose retainers
iii) Pain
Solutions:
i) If small lesion / away from margin
therefore no need to follow blacks principles restored by
cement
ii) If large proximal lesion
Therefore blacks principles should be followed restored
by amalgam / composite remake the restoration
iii) If extensive lesion pulp exposure
Therefore RCT + post and core remake the restoration
2
, 2)PULP INJURY:
Causes:
i) No coolent during preparation increase heat generation
dentin dehydration
ii) reduction therefore dentin barrier
iii) Minute un-noticed pulp exposure
iv) Absence of temporary protection
v) The use of irritating cement e.g Zn phosphate
vi) Caries
Signs and symptoms:
i) Post cementation sensitivity which is not decreased by time
ii) Intense pain
iii) Periapical abnormalities detected by x-ray.
Solutions:
RCT + post and core + remake the restoration
N.B :
RCT can be done without removal of the prosthesis i.e access
through the prosthesis which can be closed using composite or
amalgm restoration
3)PERIODONTAL BREAKDOWN:
Signs and symptoms:
i) Redness / swelling / bleeding of the gingival tissues around
the prosthesis margin.
ii) Periodontal pocket formation
iii) Bad odour / taste
3
Causes of fixed prosthesis failures:
1) Improper case selection
2) Faulty diagnosis and treatment planning
3) Faulty clinical or laboratory procedures
4) Improper care and maintenance
Classification of fixed prosthesis failures:
I) Biological failures
II) Mechanical failures
III) Esthetic failures
IV) Maintenance failures
I) BIOLOGICAL FAILURES:
1) CARIES:
Represent 36 % of biological failures
Can occur at :
a) Margin:
Causes open/ short / ill-fitted margin
Detected by sharp explorer
1
,b) Beneath restoration:
Causes incomplete caries removal
loose retainers microleakage.
Caries susceptibility under fixed partial denture is more than
under single crowns
c) Root:
Causes decrease salivary secretion especially in old aged
patient.
Commonly associated with gingival recession and
periodontal pockets.
Signs and symptoms;
i) Bad taste and breath
ii) Loose retainers
iii) Pain
Solutions:
i) If small lesion / away from margin
therefore no need to follow blacks principles restored by
cement
ii) If large proximal lesion
Therefore blacks principles should be followed restored
by amalgam / composite remake the restoration
iii) If extensive lesion pulp exposure
Therefore RCT + post and core remake the restoration
2
, 2)PULP INJURY:
Causes:
i) No coolent during preparation increase heat generation
dentin dehydration
ii) reduction therefore dentin barrier
iii) Minute un-noticed pulp exposure
iv) Absence of temporary protection
v) The use of irritating cement e.g Zn phosphate
vi) Caries
Signs and symptoms:
i) Post cementation sensitivity which is not decreased by time
ii) Intense pain
iii) Periapical abnormalities detected by x-ray.
Solutions:
RCT + post and core + remake the restoration
N.B :
RCT can be done without removal of the prosthesis i.e access
through the prosthesis which can be closed using composite or
amalgm restoration
3)PERIODONTAL BREAKDOWN:
Signs and symptoms:
i) Redness / swelling / bleeding of the gingival tissues around
the prosthesis margin.
ii) Periodontal pocket formation
iii) Bad odour / taste
3
