failure in removable part denture my ppt
TRANSCRIPT
GOOD MORNING
FAILURES IN REMOVABLE
PARTIAL DENTURE
DR ZARIR
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 occlusion8. Failure in patient-dentist relationship9. Conclusion 10. Bibliography
INTRODUCTION
Failure of removable partial dentures is due to inadequate
1. Diagnosis and treatment planning2. Mouth preparation procedures3. Design of framework4. Laboratory procedures5. Support for denture bases6. Occlusion7. 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
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
SOLUTION:-
1ST appointment:- make an assessment of the patient, diagnosis, take radiographs and make primary impression2nd 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
Failure to a the analyze set ofdiagnostic 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
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
2) SurveyingFailure to use a surveyor during treatment planning
SOLUTIONIt 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
FAILURES IN MOUTH PREPARATION PROCEDURES
1) Improper guide plane preparations:
Stewart’s Clinical Removable Partial Prosthodontics. 4th edition
2) Improper height of contour:
Improper positioning of the retentive clasp arm and reciprocal clasp arm
Retention and Stability of the prosthesis affected.
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
Occlusal rest Preparation in a multi- surface Amalgam Restoration.
-Amalgam tends to flow when placed under constant pressure or even excess preparation.
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
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
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
Incorrect use of clasp designs
Use of clasps that are too broad in tooth coverage and have too little consideration for esthetics
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
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
Framework that does not contact the tooth:-
Block out wax addedabove 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
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
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.
FAILURES IN LABORATORY PROCEDURES
1) Poor cast-forming procedures:
Cast is inaccurate: not a true
reproduction of the anatomy of the
mouth.
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
3) Refractory cast:
ERROR: Abraded refractory castSOLUTION:-1.Surface treatmentof 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
-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
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
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
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
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
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
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
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
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
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
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
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
3. Rocking of the record
4. Trimming of the record or metal showing through the record.
5. Face bow transfer not done.
3) Correction of occlusal plane:
Sensitivity of teeth or incipient caries- after enameloplasty
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
Dentists failing to select type, shade and mold of the denture teeth to be used resulting in unaesthetic prosthesis not accepted by patient
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
CONCLUSION
REFERENCES
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
REFERENCES
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
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