RPD II Flashcards
How is the Tx plan for an RPD pt finalized?
Diagnostic Assessment
*with casts
T/F
You might need to remove Tori surgically before making an RPD
True
What is the final mouth prep alteration done before accepting the definitive RPD design?
Alteration of Abutment contours
*can only be limited changes in enamel
How are major contour changes prior to RPD definitive design accomplished?
Crown
T/F
Rest seats are done entirely in enamel
True
T/F
Because rest seats are done entirely in enamel anesthesia is avoided so pt can tell dentist when sensitivity is felt
True
Prepare occlusal rest seats with medium round burs # ___ or # ___
2 or #4
Tooth prep sequence (3 things):
Guide Planes
Enameloplasty
Rest seats
T/F
Undercuts should be gentle when making enameloplasty
True
M/D measurement for Rest Seats:
2.5 mm
T/F
Alternative cingulum rests are smile shaped
True
For a Master Cast: How much space should be in the Custom Tray made by light cured resin?
How is this attained?
2 mm
Wax spacer
How many pounds should stone be vacuumed under?
27 lbs
In what 2 cases would you use Record Bases?
Not enough teeth for stable interdigitation
if mount in CR
T/F
Making Record Base: Blue line at vestibule depth, , adapt 15 mm strip of Triad, cut with Bard Parker knife
True
T/F
Do not remove material from the Intaglio Surface of a Record Base
True
How much space should there be between the Record Base and the opposing teeth?
1-2 mm
2 options for making a bite registration for a Record Base:
Notch ridge and apply PVS (Regisil), trim to cusp tips
Notch ridge and apply Aluwax, trim to cusp tips
Most states require lab work authorizations to be made in ______
Duplicate
both dentist and laboratory must keep on record for specified period
Cobalt - Chromium:
According to ANSI/ADA Specification 14, weight of chromium shouldn’t be less than ____%
Total weight of chromium, ____, and _____, should be no less than ______
20%
cobalt, nickel, 85%
Alloys used in RPD’s must comply with requirements to what 3 factors?
Toxicity
Hypersensitivity
Corrosion
Alloy minimum value for elongation:
Yield Strength:
Elastic modulus:
1.5%
500 MPa
170 GPa
3 elements accounting for 82 - 92% of weight for most dental restoration alloys?
Chromium
Cobalt
Nickel
T/F
Chromium, Cobalt, and Nickel have relatively little effect on alloy properties
True
*properties determined by carbon, molybdenum, beryllium, tungsten, and aluminum
When Chromium content is above ___%, the alloy is difficult to cast and forms a ____ phase
30%
brittle
Of the 3 main elements in RPD alloy, which 2 are interchangeable?
Which one increases elastic modulus, strength, and hardness a little more?
Cobalt and Nickel
Cobalt
T/F
Increasing Carbon content is a good way to increase hardness of alloy
True
.2% change can make alloy unusable
T/F
Molybdenum decreases strength of alloy
False
*increases
What incorporates a curved, arcuate, or variable path of placement allowing one or more of the rigid components of the framework to gain access to and engage an undercut?
Rotational Path RPD
3 Categories of Rotational Path RPD’s
Posterior to Anterior
Anterior to Posterior
Lateral to Lateral
When is the Altered Cast Method for impression making often used?
Mandibular distal extension arch forms
What procedure compensates for greater soft tissue displacement of the Mandible and is seldom used in the Maxilla?
Altered Cast
The goal of the Altered Cast is to more accurately record the soft tissues with a _______ impression
second
Gingival stippers, flippers, muco-adhesion RPD’s aks…
Provisional RPDs
Patrix into Matrix is an example of what?
Attachment Retained RPD
**precision attachment
In a precision Attachment Retained RPD, where is the receptacle usually located?
Fitting part?
Crown of Abutment tooth (matrix)
Pontic or Denture framework (patrix)
Matrix and Patrix can be switched in Extracoronal Locator Attachment
True
A Master Cast or Diagnostic Cast should have a minimum cross section of ___ to ____ mm through its narrowest section
10-12mm
T/F
Preprosthetic surgery includes removal of gross bony undercuts, enlarged tuberosities, large tori
True
If there is inflammation/irritation, distortion of anatomic features (rugae, etc) or a burning sensation of ridges, tongue, cheeks, lips - what is needed?
Conditioning of Abused/Irritated tissues
*remove insult, adjust denture
What are 3 preps for Abutment Teeth?
Enameloplasty
Existing restoration
New restoration (Survey Crown)
Class III guide planes should be how tall?
Class I or II?
2-4 mm
1.5-2 mm
Tooth prep sequence on Enamel/Existing Restorations:
4 steps
Prep guide planes
Modify contours
Alginate
Rest seat prep
When should the need for crowns on abutment teeth for RPD’s be established?
Diagnosis/Tx planning phase
Extensive caries, heavily restored teeth, ______ treated teeth, recontouring, ______, and intra or extra _____ attachments
All are indications for Survey Crowns:
Endodontically
Splinting
Coronal
Patrix to Matrix intracoronal attachment must have enough ______ on the survey crown
Occlusal space
RPD survey crown sequence of tooth prep:
4 steps
Prox/lingual guiding planes
Proximal box
Final prep
Full arch impressions
T/F
Take a Survey Crown with a Triple Tray
False
***Full Arch Impression (never triple tray)
RPD Survey Crown wax pattern formation (5 steps):
Guiding plane
Retentive undercut
Reciprocating arm
Rest seat
Cutback for PFM
How deep should rest seats be on a Survey Crown?
Survey Crown embrasure Rest Seat depth?
1.5 mm
2 mm
Prior to cementation what should be done to a Survey Crown?
Survey
What are the 2 reasons to use a Custom Tray for Final RPD Impressions?
Increases accuracy (less tissue displacement)
Lowers cost (less matl used)
Shaping the border of a custom tray by manipulating the tissues adjacent to the borders to duplicate the contour and size of the vestibule:
Border Molding
Metal Alloys must meet what 5 criteria for RPD’s?
Biocompatible
Biologically inert
Versatile (castability)
Rigidity
Resilient (proper give/flex)
Type IV gold (extra hard):
Low gold:
75% or greater Au and Pt
less than 75% Au and Pt
Cobalt Chromium %’s
***most common
60% cobalt
30% chromium
5% molybdenum
Nickel Chromium %’s
*less common
65% nickel
16% chromium
9% Molybdenum
T/F
Nickel Chromium is more common than Cobalt Chromium
False
What increases strength, hardness, and casting temp?
What increases ductility, decreases strength and casting temp?
What increases corrosion resistance?
Cobalt
Nickel
Chromium
3 advantages to Base Metal Allow vs Gold:
2 advantages:
Decrease weight, cost, Increase corrosion resistance
casting technique, clasp adjustability
T/F
Gold must be thicker to achieve same rigidity and therefore has more bulk in pts mouth
True
The addition of what will cause the Framework or an RPD to seat tighter and prevent food impaction?
Bead lines
3 Types of Block Out:
Shaped (follows contour)
Parallel (guide planes)
Arbitrary (undercuts could be anywhere)
To make a Framework, you make a _____ cast from a duplicate master cast, wax up, add _____ and Invest with ______
(then burn out the wax pattern and cast framework)
Refractory
Sprue
Ethyl Silicate
The Ethyl Silicate Investment is removed from the casted framework with what?
sand blaster
T/F
The framework can be electrolytically polished
True
T/F
You can section and solder a frame that isn’t fitting correctly
True
What is the step after fabrication?
Try in
*must be passive fit
If the impression is distorted, the framework will not fit ______
Passively
3 Types of Indicating Medium for Framework Insertion/Adjustment:
Aerosol spray (doesn’t convey distance)
Disclosing Wax (conveys distance)
Silicone (Fit Checker - expensive)
T/F
With opposing frameworks, adjust the arches together
False
**individually, then together
Show through means you have what?
Incompletely seated framework
A negative likeness of a portion/portions of edentulous denture bearing areas made independent of and after the initial impression of natural teeth - employs impression tray attached to RPD framework.
Altered Cast Impression
An Altered Cast Impression must capture what 2 things?
How?
Anatomic Ridge Form - frame impression
Functional/Supporting Ridge Form - selective pressure
A custom tray should be ___ mm short of the vestibule
2-3 mm
An Altered Cast gives you ______, not ______ of the Edentulous Ridge
Functional form
Anatomical form
An Occlusal Record is taken with what?
Record Base and Wax Occlusal Rim
The final record in the Record Base/Wax Occlusal Rim should have how much separation from wax to teeth?
1-2 mm
Complete Natural Dentition has what type of Occlusion?
Partial Edentulism?
Complete Edentulism?
MIP
MIP or MIP=CR
MIP=CR
The best fit for the teeth regardless of Condylar Position:
MIP
CR:
superior/anterior position of condyle
You should always mount the occlusal relationship by considering which arch?
Weaker
Tooth borne RPD vs Natural Dentition:
Tooth borne RPD vs Complete Denture
Tooth mucosa RPD vs Natural Dentition
Tooth mucosa RPD vs Complete Denture
Tooth mucosa RPD vs Tooth mucosa RPD
MIP
CR (balanced occlusion)
MIP
CR
CR
CR should be in Balanced Occlusion in _____ positions while MIP should provide working side contacts in what positions?
Eliminate what interferences?
Eccentric
Eccentric
Excursive
3 methods to establish occlusal relationships:
Hand articulate
Interocclusal reg
Record bases w/ interocclusal reg
What denture tooth material is most often used?
What isn’t used any more?
Acrylic resin
Porcelain
Replacement teeth should oppose natural teeth with minimal wear and what tooth form?
22 or 33 degree cuspal inclination
External finish line:
Internal finish line:
undercut
butt joint (90 degrees)
RPD acrylic resin added how?
Wax up, invest, burnout, acrylic resin mixed, adapted
3 steps in delivery of RPD:
Denture base fit
Correct occlusion
Adjust retentive clasps
How is the Intaglio of the denture base checked?
Same direction PIP
pressure indicating paste
What 2 materials are used to detect pressure spots in an RPD?
Where are they used?
PIP for Intaglio
Disclosing wax for edges of denture borders
What should you do if there are large occlusal discrepancies?
Clinical Remount
Adjust Clasp with Bird Beak, what technique?
Adjust Clasp with Three Prong, what technique?
hold pliers and move frame
squeeze gently
2 reasons not to use bleach:
pores on acrylic resin
corrode metal
3 post delivery adjustment time scale:
24 hours
72 hours
1 week
After 24 hour, 72 hour, and 1 week adjustments to RPD’s, what is the recall schedule after that?
6 month hygiene
annual periodic (clinical/radiographic)
Resurfacing the tissue side of RPD w/ new base matl
Reline
Lab process of replacing entire denture base matl on existing prosthesis
Rebase
2 Types of Reline:
Direct
Indirect
T/F
Denture base repair by opening up, repair resin, cure in vacuum
True
RPD designed for esthetics, stabilization/function used for limited time
(often used to assist determination of therapeutic effectiveness prior to definitive prosthesis)
Interim RPD
Interim RPD that adds artificial teeth upon loss of natural teeth
Transitional RPD
Prosthesis to treat/condition tissues
placed in prep for future therapy
Treatment RPD
Examination and Diagnosis
Survey/design of diagnostic casts
Tx plan
Mouth prep
Final impressions
Survey/design master casts
Work authorization form
RPD Tx sequence
Framework try-in
Altered cast impression
Record bases
JRR
Esthetic tooth try in
Processing
Lab remount
RPD Tx sequence
Finish/polish
Clinical remount at delivery
Post op instructions
Post delivery adjustment
RPD Tx sequence
the distal extension should go how far onto the Retromolar Pad?
1-2 mm
Clean once a day
Remove at night
No bleach
RPD post op instructions
