This document discusses common failures in removable partial dentures (RPDs). It is outlined in sections corresponding to different stages of RPD fabrication: diagnosis and treatment planning, mouth preparation, framework design, laboratory procedures, denture base support, occlusion, and patient-dentist relationship. Specific errors are described for each stage, such as improper diagnosis, guide plane preparations, framework design transfer, casting defects, and packing of acrylic resin. Solutions are provided for many of the errors, such as using diagnostic casts and surveys for treatment planning, ensuring relief wax thickness is adequate, and allowing flask packings to fully cool before deflasking. The document emphasizes the importance of each step of RPD fabrication for producing successful prostheses.

1. GOOD
MORNING

2. DR ZARIR

3. CONTENTS
1. Introduction
2. Failures in diagnosis and treatment planning
3. Failures in mouth preparation
4. Failures in framework design
5. Failures in laboratory procedures
6. Failure in support for denture bases
7. Failures in occlusion
8. Failure in patient-dentist relationship
9. Conclusion
10. Bibliography

5. Failure of removable partial dentures is due to
inadequate
1. Diagnosis and treatment planning
2. Mouth preparation procedures
3. Design of framework
4. Laboratory procedures
5. Support for denture bases
6. Occlusion
7. Patient-dentist relationship
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261

6. Making RPD’s using a 2 appointment system: one for diagnosis
definitive impressions, mouth preparation procedures and
second for insertion of partial denture.
FAILURE IN DIAGNOSIS AND TREATMENT
PLANNING
A.ERROR:-
1. IMPROPER DIAGNOSIS
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261

7. SOLUTION:-
1ST appointment:- make an assessment of the patient,
diagnosis, take radiographs and make primary impression
2nd appointment:- make mouth preparations and impressions
for definitive casts and jaw relation can also re carried out.
3rd appointment:- try in of the metal framework
prosthesis.
4th appointment to deliver the denture and adjust the occlusion.
Give the patient instructions essential to successful function and
maintenance of the denture
5th mandatory follow up
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261

8. Failure to a the analyze set of
diagnostic casts for each patient.
B.ERROR:-
SOLUTION:-
1.After only an intraoral examination, a patient
may appear to have a simple problem when, in
fact, the situation is very complicated.
2. Always make diagnostic casts and evaluate them
thoroughly before committing to treatment
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261

9. C. ERROR:-
Failing to remove debris and plaque from the teeth before
impression is made
Routinely clean the teeth
with a lubricating
prophylactic paste before
making an impression,
In cases of extensive calculus
deposition oral prophylaxis
has to be carried out
SOLUTION:-
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261

10. 2) Surveying
Failure to use a surveyor during
treatment planning
SOLUTION
It is the responsibility of the
dentist to survey and draw the
design on the diagnostic cast
before sending it to the lab
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261

11. FAILURES IN MOUTH PREPARATION PROCEDURES
1) Improper guide plane preparations:
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

12. 2) Improper height of contour:
 Improper positioning of the
retentive clasp arm and
reciprocal clasp arm
 Retention and Stability of
the prosthesis affected.

13. 3) Rest and Rest Seat
Preparation:
Movement of the
abutment tooth or sliding
of the prosthesis
The forces transmitted
from the prosthesis to
abutment teeth would
occur against the inclined
plane.
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

14.  Occlusal rest Preparation in a multi-
surface Amalgam Restoration.
-Amalgam tends to flow when placed
under constant pressure or even excess
preparation.

15. ERROR:-
SOLUTION:-
Dentist failing to tripod the
designed diagnostic cast
When the dentist designs the cast
it has to be tripoded so that the lab
technician can easily duplicate the
design.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261
FAILURES IN DESIGN OF FRAMEWORK
1.Tripoding

16. 2. Design transfer to master cast:
1. The design has to be outlined on the
refractory cast with minimum pressure.
2. The cast must not be abraded
during the transfer of the design
3. The position of individual clasp
tips is most important in the
design transfer
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

17. 3) Incorrectly located
RPD components:
 Incorrectly located
major connector
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition
1. Flexible major connector
2. Impinging on the
gingival margins
3. Failure to provide relief where
is crosses the gingival margins

18.  Incorrect use of clasp
designs
Use of clasps that are too
broad in tooth coverage and
have too little consideration
for esthetics

19. 4) Beading of the cast:
 Tissue blanching and
inflammation or
ulceration seen when the
beading on the cast done
too deep
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

20. 5) Block out:
 Improper seating
of the framework:-
-Block out if not done
properly permitting
rigid part of the
framework to be
placed in undercuts.
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

21.  Framework that does
not contact the
tooth:-
Block out wax added
above the height of
contour line or on the
guiding planes and not
removed during shaping
of wax.
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

22. 6) Contouring of the block out wax:
1. Done with blockout instrument properly positioned,
excess wax is carefully removed.
2. The blockout instruments can be electrically heated
or warmed over a flame
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

23. 7) Relief:
.
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition
ERROR:- Metal framework impinges on
the soft tissue
SOLUTION:-
1. The thickness of the relief wax has to be
adequate
2. The wax must not be separated and
lifted up from the cast during duplication.

24. 1) Poor cast-forming
procedures:
Cast is inaccurate: not a true
reproduction of the anatomy of the
mouth.

25. 2) Duplication:
1. Block out and relief wax
melted by reversible
hydrocolloid.
2. Mold damaged during
removal of the master
cast.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261

26. 3) Refractory cast:
ERROR: Abraded refractory
cast
SOLUTION:-
1.Surface treatment
of the cast has to be carried out.
2. The cast must not be retrieved
until it is completely set.
3. The refractory cast is then
trimmed on a dry cast trimmer.
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

27. 4) Waxing:
ERRORS:- patterns separate from
the refractory cast.
SOLUTION:-
1. The plastic patterns have to be
glued properly to the design
outline on the refractory cast
2. Mixture of acetone and plastic
pattern scraps mixed to watery
consistency ( TACKY LIQUID)
3. The liquid has to be applied in a
very thin layer
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition

28. 5) Failure of technician to
follow the design and
written instructions:
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part I.
J Prosthet dent; 2001;86(3); 251-261

29. 6) Spruing
ERROR:-
1. Attaching the sprue lead to a
thin section of waxed framework
SOLUTION:- Always
sprue to the bulkiest portion
of the pattern
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II.
J Prosthet dent; 2001;86(3); 251-261

30. Small particles of investment in the casting:-
-Sprue leads joined to main sprue on wax
pattern improperly.
-Sprue hole was enlarged by cutting with
knife, leaving roughened surface for metal
to flow over.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II.
J Prosthet dent; 2001;86(3); 251-261

31.  Metal spilled when casting:-
-Sprue hole is too small for Bulk of metal.
-Sprue leads broken during investing
procedure
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II
J Prosthet dent; 2001;86(3); 251-261

32.  Internal mold deformations:-
-Constriction in the sprue lead
 Porosity in casting:-
-Improper spruing procedure
 Pattern failed to casting:-
-Pattern separated from crucible former during
investment
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II.
J Prosthet dent; 2001;86(3); 251-261

33. 7) Investing:
If the cast is dried with teeth up,
white materials would be
deposited around the teeth. This is
due to deposition of salts which
form a positive layer that cannot
be removed without scraping and
damaging the cast.
 Cracks in the cast
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III.
J Prosthet dent; 2001;86(3); 251-261

34. 8) CASTING defects:-
 Pitted casting
If the design is placed on the refractory cast with a
graphite pencil….
Contaminates…..
Burn out temperature…..
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II.
J Prosthet dent; 2001;86(3); 251-261

35.  Metal nodules and rough area on cast
framework
-Failing to use surface tension reducer correctly
on the waxed patterns would cause air trap, when
paint on investment flows
-If the surface tension, reducer is not allowed to dry
before applying the paint on investment
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II.
J Prosthet dent; 2001;86(3); 251-261

36.  Incomplete casting and rough areas or fins
in casting
-W: P ratio.
-If paint on investment layer is too thin.
-If the paint on layer is too thick.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II.
J Prosthet dent; 2001;86(3); 251-261

37.  Porous cast frame
work
If the mold moves in the
casting machine as the
casting arm starts to spin,
molten metal sometimes
may miss the sprue hole
and spill outside the mold.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II.
J Prosthet dent; 2001;86(3); 251-261

38.  Incomplete casting
1. If the sprue hole faces
upward during burn out.
2. Casting temperature
of metal….
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part II.
J Prosthet dent; 2001;86(3); 251-261

39.  Warpage of the
Frame work
1.The air pressure of the
nozzle of air abrasion
machine is about 100 psi…..
2.If sufficient time is not
allowed for the metal to cool
to room temperature in the
investment (quenching the
mold)…..
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

40.  Nicks on the metal
casting
1. Carelessly cutting off the
sprue leads
2. Using the wrong mandrel
in high spread lathe
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

41.  Framework is too loose
Carelessly grinding the
inside of clasps
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

42.  Fracture of the clasps
Removing too much metal
from retentive clasps.
An improperly tapered
clasp or one that is thin
or having nicks encourages
breakage by concentrating
the strain….
Electro polishing for a
longer time.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

43.  Warpage of the
framework
Abrasive rubber wheels and
points can build up heat in the
framework very quickly
 Loose frame work
Polishing removes a definitive
layer of metal.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

44.  Distorted frame
work
1.Clasps and other parts of
the frame work can easily
catch in the polishing
wheel.
2.The force
usually distorts the
framework and injures the
operator.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

45.  Incomplete Casting of
the Metal frame work
1. Metal too cold when cast.
2. Improper spruing.
3. Gas trapped in mold.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

46. 9) Mixing and packing
acrylic resin:
1. Packing the acrylic material
into the flask before allowing
them to cool down at room
temperature
2. Packing the resin into the
flask before it is ready to
pack.
3. Underfiling the mould.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

47. 10) Deflasking and polishing the removable
partial denture:
1. Distorted framework
2. Increase in the vertical dimension
3. Warpage of framework
4. Scratches on the final metal framework
5. Damaged denture teeth
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

48.  Distorted clasps
-Using a cloth wheel that was not broken
properly would result in damaged removable partial
denture or injure the operator.
-A new cloth wheel has strings of material
protruding from it.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

49. -The strings could
tangle in the clasp or other
parts of removable partial
denture and snaps the
removable partial denture
from the operator’s hands
throwing it out with great
force.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

50.  Scratches on the denture
-Course pumice leaves scratches.
-It would be difficult to adequately polish around
the necks of denture teeth with a cloth wheel or a lathe
mounted bristle brush without damaging the contours
of the teeth.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

51.  Dull appearance of the denture
Detergent alone would not adequately remove
polishing compound from the removable partial
denture.
The remaining residue would prevent the
removable partial denture from achieving the luster.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

52. 11) Fitting the
framework to the cast
and mouth:
1. Framework too retentive on
the definitive cast.
2. Frame Work not fitting
exactly in the mouth.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

53. 12) Finishing and polishing of framework:
 Polished surface is dull with fine scratches
-Sequence of finishing steps not followed
 Major and minor connector over thinned and
flexible.
-Framework over thinned with abrasive stones
during finishing
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

54.  Clasps is nicked or
notched
 Framework
distorted
-Frame work caught
in lathe during finishing.
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

55. 13) Fitting and adjusting the removable partial
denture to mouth :
 Failing to evaluate the denture borders when
placed intra-orally.
 Loss of retention and support.
 Soreness or Ulceration of soft tissue in the
patient’s mouth
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

56.  Increase in the vertical dimension of
occlusion
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

57. Warpage of the RPD
-If the patient does not seat the
removable partial denture correctly, they
may warp the removable partial denture or
be injured by it

58.  Inadequate ridge quality and
contour
 Complete extent of the
residual ridge not covered by
the denture
 Inadequate coverage of
basal seat tissues
 Failure to record basal seat
tissues in supporting form
FAILURE IN SUPPORT OF DENTURE BASE

59. 1) Articulation:
Error in articulation of the cast
FAILURES IN OCCLUSION
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

60. 2) Face bow transfer:
 Alteration in the jaw
relation
1. Positioning the face bow on
patient’s face.
2. Placement of the fork
Rudd & Rudd, A review of 243 errors possible during the fabrication of a removable partial denture: Part III
J Prosthet dent; 2001;86(3); 251-261

61. 3. Rocking of the
record
4. Trimming of the
record or metal
showing through the
record.
5. Face bow transfer
not done.

62. 3) Correction of occlusal plane:
 Sensitivity of teeth or incipient caries-
after enameloplasty

63. 4) Selecting and arranging teeth:
 Unable to interdigitate artificial teeth with
opposing natural dentition
 Insufficient space to set posterior tooth
replacement
 Anterior replacement teeth too short for
satisfactory esthetics

64.  Dentists failing to select type, shade and
mold of the denture teeth to be used
resulting in unaesthetic prosthesis not
accepted by patient

65. FAILURE IN PATIENT-DENTIST RELATIONSHIP
 Failing to make a follow up appointment for
the patient
 Failure of dentist to provide adequate
dental health care information, including care
and use of prosthesis

67. 1. Rudd & Rudd, A review of 243 errors possible during
the fabrication of a removable partial denture: Part I
& . J Prosthet dent; 2001;86(3); 251-261
2. Rudd & Rudd, A review of 243 errors possible
during the fabrication of a removable partial denture:
Part II & . J Prosthet dent; 2001;86(3); 262-276
3. Rudd & Rudd, A review of 243 errors possible
during the fabrication of a removable partial denture:
Part III & . J Prosthet dent; 2001;86(3); 277-286

68. 4. McCracken’s: Removable partial Prosthodontics. Eleventh
edition 2005
5. Stewart’s Clinical Removable Partial Prosthodontics.
fourth edition
6. A clinical overview of removable prostheses:3. principles
of design for removable partial denture .Dent update
2002;29.
7. A clinical overview of removable prostheses:4
technological consideration when designing removable
partial denture. Dent update 2003;30:7-9

69. THANK
YOU