RPD HOLY GRAIL Flashcards
Which of the following are done last?
A) Framework try in
B) Create rests
C) CR Record
D) Altered cast
D) Altered casts; assure support for RPD
List the order of the following:
- CR Record
- Framework try in
- Altered cast
- Create rests
- Framework try in
- Create rests
- CR Record
- Altered cast
If an RPD is part of planned treatment; plan the RPD:
Before beginning any other treatment
These are the clinical steps for an RPD fabrication
1. Diagnosis, treatment plan, hygiene
2. Diagnostic casts
3. Draw design & list abutment modifications on the prosthesis design page
4. Instructor approval
5. Complete Phase I treatment
6. Abutment modifications
7. Preliminary impression to check abutment modifications
8. Fabricate and cement crowns or fixed partial dentures
9. Final framework impression
10. Make two casts
11. Draw design on 2nd cast
12. Instructor approval/ corrections of drawing/design on cast
13. Complete RPD framework prescription (instructor signature required)
14. Second pour cast with design sent to lab with first pour
15. Inspect wax-up
16. Framework adjustments (create rests)
17. Altered cast impressions if needed
18. Jaw relation records (CR record)
19. Select & set denture teeth
20. Try-in with teeth in wax
21. Process, adjustment, deliver to patient (altered cast)
How far distally should the denture base extend in a class 1 distal extension case?
2/3 of the retromolar pad
Bilateral edentulous area posterior to remaining teeth describes:
Kennedy Class I
Maxillary framework extends (in Kennedy class I)
2/3 distance to hamular notch (resin engages further)
How far distally should the retention extend for a distal extension case?
Extends to 2/3 from the guide plate to 2/3 of the retromolar pad
Which of the following is the hardest to obtain with a distal extension case?
VDO record (possibly also establishing plane of occlusion)
Essential to prevent displacement or deformation of the metal framework during resin-packing procedures
cast stop
Cast stops project from the tissue surface of the ____ to contact the ___
minor connector; dental cast
A ____ should be used to join acrylic resin and metal components at the internal surface of an RPD
butt joint
A butt joint should be used to join ____ an d____ components at the ____ surface of an RPD
acrylic resin; metal components; internal
Each internal finish line of a butt joint should display an angle of:
90 degrees
The internal angles of external finish lines should be:
sightly less than 90 degrees
The internal angles of external finish lines should be slightly less than 90 degrees, what does this result in?
improved mechanical retention for acrylic resin components
In a butt joint the internal angle = ____; the external angle = ____
internal= 90
external= acute
Base plate wax on cast for relief in edentulous areas:
wax patterns
Wax patterns are made on the:
refractory cast
The cast that is used for fabricating the framework:
refractory cast
What does “support” mean for direct retainers?
resists vertical movement towards the soft tissue
Resistance to removal from the tissues or teeth:
retention
Resistance to movement in a horizontal direction (anterior-posteriorly or medio-laterally)
Stability
Resistance to movement towards the tissues or teeth:
Support
A tooth that supports a partial denture:
abutment
A component of a partial denture that provides both retention and support for the partial denture:
retainer
What three components are required clasp assembly?
support, resistance & retention
T/F: The completed RPD must be passive
true
T/F: The RPD should exert forces on the teeth and soft tissue
false- the RPD should NOT exert forces on the teeth or soft tissue
T/F: The toe of each retentive clasp should lie passively in a measured undercut
false- The tip of each retentive clasp should lie passively in a measured undercut
Where should the tip of each restive clasp lie?
passively in a measured undercut
Clasps should be ____ when fully seated, meaning:
passive; not directing force on the tooth
The reciprocal arm of the clasp should contact the tooth:
before the retentive tip passes the height of contour
The reciprocal arm of the clasp should contact the tooth before the retentive tip passes the height of contour so it can:
hold the tooth in place as the retentive tip puts off-axis pressure on it
The reciprocal arm of the clasp should contact the tooth before the retentive tip passes the height of contour so it can hold the tooth in place as the retentive tip puts off-axis pressure on it. This:
neutralizes the stress from the retentive tip
T/F: A class I lever is ideal. RPI is an example of a class I lever.
False; false
Class I Lever=
most detrimental
Class II lever=
ideal- RPI is an example of a class II lever
RPI is an example of a:
class II lever
RPI stands for:
Rest (mesial), Proximal plate, I-bar
What type of support allows for an RPI?
Tooth tissue (class I, II, & long class IV)
Does an RPI satisfy the principle of encirclement?
NO
RPI= class II lever =
stress release
Wrought wire needs an elongation factor of:
more than 6%
It is important that a wrought wire clasp have an elongation percentage of more than 6% (PTQ) allowing _____ without microstructure hangers that could compromise its physical properties (like creating a fracture)
allowing clasp to bend
Check biting is caused by:
a) lack of horizontal overlap
b) Mandibular teeth too far buccal
Moving the buccal cusp lingually increases
horizontal overlap
Caused by insufficient overlap between maxillary and mandibular teeth:
cheek biting
If artificial teeth are correctly positioned and cheek biting occurs:
round the buccal cusps of mandibular posterior teeth to move buccal cusps slightly lingually (thereby creating a greater horizontal overlap)
If cheek biting occurs and artificial teeth are incorrectly positioned or rounding does not help:
remove the artificial teeth and reset them
Caused by the artificial teeth being positioned too far lingually, resulting in a decrease in tongue space:
tongue biting
Tongue biting is caused by the artificial teeth being positioned too far _____, resulting in a ____ of tongue space
lingually; decrease
How do you fix tongue biting?
by rounding lingual cusps/recontour lingual surface
What would the following alterations help?
- gentle “rounding or rolling” of lingual cusps and recontouring of the lingual surfaces of the mandibular teeth
tongue biting
What do you do if tongue biting continues after teeth have been reshaped?
Remove and reset artificial teeth
Which of the following doesn’t call for a rebase?
dentition or moveable
_____ is a laboratory technique in which the bulk of the denture base is removed and replaced using new resin
rebasing
The rebasing approach results in a ______, but is technically complicated by the fact that the retentive meshwork is buried within the denture base- often without sufficient relief beneath the mesh to allow for adequate bulk of new resin
base of uniform quality
Rebasing is indicated when: (3)
- denture bases do not extend to cover all of the denture bearing tissues
- denture base has been fractured
- denture base has become irreparably discolored
- denture bases do not extend to cover all of the denture bearing tissues
- denture base has been fractured
- denture base has become irreparably discolored
What would you do for the listed situations?
rebase
_____ when both denture base and denture teeth need work
____ when atleast 2mm is present under denture base OR indirect retainer lifts 2mm+
Remake; Reline
When should you reline the denture base?
- when atleast 2mm is present under denture base
- when indirect retainer lifts 2mm+
The anterior teeth disclude the posterior teeth when the mandible moves in protrusion:
anterior guidance
Anterior guidance describes the anterior teeth disclude the posterior teeth when the:
mandible moves in protrusion
With anterior guidance, the ____ , ____, and ____ disclude the posterior teeth when the mandible moves in protrusion
canines; central incisors; lateral incisors
With anterior guidance, the canines, central incisors, and lateral incisors disclude the posterior teeth when the mandible moves in:
protrusion
Contacts between the posterior teeth during excursive movements are considered ____ that can create damaging effects on the teeth and periodotnium.
interferences
With anterior guidance, describe what should occur with the posterior teeth:
Posterior teeth SHOULD NOT touch (in excursive movements)
These create off-axis forces in posterior teeth, where you’re close to the TMJ. Meaning high load in off-axis direction, leading to damage to the teeth
Interferences (posterior teeth)
Which of the following are involved in support?
A) Rest
B) Major connector
C) Denture base
D) All of the above
D) All of the above
What material is most commonly used to make denture bases?
PMMA
What denture base material is being described?
- Difficult to adjust
- Poor esthetics
- Part of cast framework
- Good thermal conductivity
- Can be kept thin
Metal
What denture base material is being described?
- Acrylic resin
- Most common
- Easily adjusted and relined
- Good esthetics
- Attached to framework by lattice or mesh
Polymethyl methacrylate (PMMA)
_____ is the most common material used for a denture base
PMMA
What type of material should be used in distal extension cases?
PMMA
What type of joint should be used with PMMA?
Butt joint (90 degrees) with major and minor connector
Can you reline a PMMA base?
yes
Advantages of acrylic resin bases (PMMA) (3):
- ability to reline the base as the supporting tissue changes
- Esthetically superior to metal bases
- Ease of repair
Disadvantages of acrylic resin bases (PMMA) (4):
- Dimensional stability less than metal base- warpage
- Lower strength than metal- long spans
- Porous- hygiene
- Low thermal conductivity
What occurs if instead of a butt joint (90 degrees) for acrylic resin bases, a feathered edge is used?
distortion, breakage, or separation from the framework causing injury to the underlying soft tissue
Which of the following is true about PIP? For the false options make them true!
A) PIP means pink indicating paste
B) Should be put on camio surfaces
C) Should be put in great amounts
D) Should be in brush strokes
True: D- should be in brush strokes
A- PIP means pressure indicating paste
B- Should be put on intaglio surface
C- Should be put in small amounts
Checks soft tissue impingement during framework adjustment step:
PIP
PIP is placed on the ____ surface to check for ____ areas
intaglio; pressure
If clasps are tight on a class III with circumferential clasp you use what to adjust?
A) 139
B) Hemostat
C) 200
D) Remake
A- 139
A class III is ___ supported
tooth
Indications for circlet:
undercut OPPOSITE of edentulous site
An undercut adjacent to the edentulous site means NO:
circlet
For adjusting retentive clasps as a general rule, at the time of insertions ____ retention should be used
slightly less than maximum
Only the ____ should be used when adjusting a half round cast circumferential cast
139 plier
Only the 139 plier should be used when adjusting:
half round cast circumferential clasp
Clasps should be adjusted in:
small increments
Excessive bending of a clasp in one direction only will lead to:
accelerated fatigue and failure of the clasp
The surveyor is used for:
a) undercuts
b) interferences
c) path of draw
d) all of the above
d) all of the above
If there isn’t a lot of inter arch space, what material should be used for the denture base?
metal
Metal bases cannot be relined so they are generally not used for:
tooth-tissue borne removable RPDs or in areas where teeth has been removed in 12 months
Why are metal bases not used for teeth that have removed within 12 months?
resorption will still be occurring at an increased rate, and relining will usually be required
T/F: All distal extension cases require clinical remount. All class 3 might require clinical remount
first true; second false
All ____ cases require a clinical remount
distal extension
All ____ supported RPDs will require clinical remounting
tooth-tissue
Which of the following will require a remount?
a) class III tooth supported
b) class I tissue supported
c) Class II tissue supported
B & C
Chromium-cobalt shrinks:
2.2-2.4 %
What metal is used at UMKC?
CoCr
Why is CoCr used more than NiCr?
due to nickel allergy
Possible causes of failure of chromium-cobalt alloys include:
- cold-working
- shrinkage-porosity
- low percent elongation
- excessive carbon in the allow
Cause of chromium-cobalt failure that reduces the percentage of elongation that causes a decrease in hardness:
Cold working
Cause of chromium-cobalt failure due to the alloys shrinking approximately 2.3% resulting in porosity
shrinkage porosity
Cause of chromium-cobalt failure directly related to greater brittleness
low percentage elongation
Cause of chromium-cobalt failure that involves reactions with other constituents to form carbides:
excessive carbon in the alloy
which occurs last?
A- altered cast technique
B- CR record
C- Framework made
D- Rest created
A- Altered cast technique
Put the following in order:
- create rests
- framework try-in
- altered casts
- CR record
- framework try in
- create rests
- CR record
- altered cast
What is the purpose of an altered cast impression?
To capture an accurate relation between the teeth, framework, and residual ridge (in distal extension cases)
What do you need a clinical remount?
interocclusal record (jaw relation)
Clinical remounting procedure:
- face bow preservation
- pickup impression
- block out undercuts
- remount cast and interocclusal record
- articulate
Describe a pick up impression:
When you insert the RPD in the mouth, then take an impression so that the impression pick ups the RPD plus shows where the teeth are
Which of the following is NOT an advantage of chromium-cobalt alloys?
A- low density (weight)
B- high modulus of elasticity (stiffness)
C- low material cost
D- resistance to tarnish
E- increased flexibility
E- increased flexibility (we want rigid; not flexible)
Necessary to ensure that the partial denture functions as one unit:
rigidity
If the denture flexes, ____ & ____ can be compromised
cross arch stabilization and stress distribution
A major connector can be made more rigid by:
using a more rigid alloy (CrCo)
Chromium cobalt alloys are ___ in comparisons to gold or palladium alloys
more rigid
Chromium cobalt alloy stiffness can be overcome by including:
wrought-wire retentive elements in there framework
_____ alloys are approximately twice as flexible as the ____ alloys
gold alloys; chromium cobalt alloys (PTQ)
Kellys Combination syndrome would present as:
Lack of osseous tissue in the anterior maxillary
What does NOT describe Kelly’s combination syndrome:
- Lack of osseous tissue in the anterior maxilla
- Loose tissue in the posterior maxilla
- Intrusion of the mandibular anteriors
- cystic palatine nerve
Loose tissue in the posterior maxilla
T/F: Guide plane should be 1/2 distance between cusp tips. Guide plane is as wide as rest.
Both true
How wide should the guide plane be?
- as wide as the widest portion of the occlusal rest
- 1/3 the BL width of the tooth
- 1/2 distance between cusp tips
With a guide plane, the normal tooth contour is maintained:
buccolingually
T/F: The gingival margin to superior border of lingual bar is 3-4 mm. Measure the distance on the cast, not in the mouth.
First statement true; second statement false. Measure the gingival margin to superior border of lingual bar in the mouth
Beaded border depth:
1mm deep; 1.5mm wide
a prepared groove on the master cast along the designated borders of maxillary major connectors:
bead
What is the purpose of a bead?
- increased rigidity
- guide for finishing
- compensate for casting inaccuracies
- displaces soft tissue, prevent food/air/fluid collection
What is the primary action of a bead?
displaces soft tissue, preventing food/air/fluid collection
Describe the dimensions of a beaded border:
using 1/2 round bur, 1 mm deep and 1.5 mm wide; feathers out to nothing 6mm from the free gingival margin; shallower over the mid palatal suture
If you have a large inoperable torus you need to use:
horseshoe
If you have a very high palatal vault you need to use:
horseshoe
I-bar with distal extension does NOT use:
DF undercut (it does use MF and mid-f)
Papillary hyperplasia is all except:
destructive bone disease
Papillary hyperplasia is a form of:
denture stomatitis
Where is papillary hyperplasia found at?
palatal vault
Causes of papillary hyperplasia include:
- local irritation
- poor fitting dentures
- poor oral hygiene
- leaving denture in 24 hrs a day
Treatment for papillary hyperplasia includes:
- educate patient on oral hygiene
- advise patient to leave denture out at night
- soak denture for 30 min in 1% sodium hypochlorite & rinse thoroughly
- use tissue conditioner
- patient should brush irritated area lightly with a soft brush
T/F: A cingulum rest is placed between the incisal and middle one third of incisors
False- its near the cervical end for maxillary anterior teeth
Indications for lingual rest seats include:
- primarily maxillary canines- not incisors
- canines with gradual lingual slope
____ transmits the forces along the long-axis of the tooth; prevents migration
Postive rest seat
A positive rest for a cingulum rest is used because:
it prevents lateral movement
A positive rest for a cingulum rest directs forces:
toward long axis of tooth
A surveyed crown is indicated when:
a- the survey line is in the gingival 1/3
b- no undercuts exist on abutment teeth
c- with the help of enamels-last, one cannot have the changes necessary for the abutment teeth without cutting into dentin
d- all of the above are true
all of the above are true
Indirect retainers have all of the following characteristics except:
Its a DO rest on a posterior abutment (Want as far forward as possible so use an MO)
Hyuperplastic tissue should be removed prior to construction of your RPD to:
provide a firm, stable base for the denture
Before construction of a CD or RPD, it is very important to:
surgically remove the hyperplastic tissue
The best impression technique for a patient with loose hyperplastic tissue is to:
register the tissue in its passive position (PTQ)
