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 cast (assures support for RPD)
List the correct order of the following:
-CR record
-altered casts
-Framework try in
-creates rests
- Framework try in
- create rests
- CR record
- altered cast
If an RPD is part of the treatment plan, plan the RPD before beginning:
any other treatment
These are the clinical steps for an RPD fabrication:
- diagnosis, treatment plan, hygeine
- diagnostic casts
- draw design & list abutment modifications on the prosthesis design page
- instructor approval
- complete phase 1 treatment
- abutment modifications
- preliminary impression to check abutment modifications
- fabricate & cement crowns or fixed partial dentures
- final framework impression
- make two casts
- draw design on 2nd cast
- instructor approval/corrections of drawing/design on casts
- complete RPD framework prescription (instructor signature required)
- 2nd poured cast with design sent to lab with 1st pour
- inspect wax up
- framework adjustments (create rests)
- altered cast impressions (if needed)
- jaw relation records (CR record)
- select & set denture teeth
- try-in with teeth & wax
- process, adjustment, deliver to patient (altered cast)
How far distally should the denture base extend in a class I 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 ____ & ____ 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:
slightly less than 90 degrees
The internal angles of external finish lines should be slightly less than 90 degrees, what does this result in?
This results in improved mechanical retention for acrylic resin components
In a butt joint:
internal=_____
external= ____
internal= 90
external=acute
Base plate wax on cast for relief in edentulous areas:
Wax patterns
Wax patterns are made on the:
Refractory casts
The cast that is used for fabricating the framework:
Refractory cast
What does “support” mean for direct retainers?
Resists vertical movement toward the soft tissues
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 for clasp assembly:
support, resistance & retention
T/F: The completed RPD must be passive
True
T/F: The RPD should exert forces on the teeth & soft tissue
False- the RPD should NOT exert forces on the teeth or soft tissue
T/F: The toe of each retentive claps 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 retentive 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 clasp puts off-axis pressure on it. This:
neutralizes stress from the retentive tip
T/F: Class I lever is ideal. RPI is a 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 what type of lever?
Class II
RPI stands for:
Rest (mesial) Proximal plate I-bar
What type of support allows for an RPI?
Tooth-tissue support (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 the clasp to bend
Cheek biting is caused by:
a) lack of horizontal overlap
b) mandibular teeth too far buccal
Moving the buccal cusps lingually increases:
horizontal overlap
Caused by insufficient horizontal overlap between maxillary & mandibular teeth:
Cheek biting
If artificial teeth are correctly positioned and cheek biting occurs:
round the buccal cusps of the mandibular posterior teeth to move the buccal cusps slightly lingually (thereby creating a greater horizontal overlap)
If cheek biting occurs artificial teeth are incorrectly positioned or rounding does not help:
remove artificial teeth & 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 the lingual surfaces of mandibular teeth
What would the following alterations help?
-gentle “rounding or rolling” of the lingual cusps and recontouring of the lingual surfaces of the mandibular teeth
tongue biting
What do you do if you have tried to correct tongue biting with rounding of the lingual cusps and recontouring of the lingual surfaces of mandibular teeth, yet the patient is still tongue biting?
Remove & reset artificial teeth
which of the following foes not call for a rebase?
dentition or moveable
A laboratory technique in which the bulk of the denture base is removed and replace 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 following situations?
Rebase
_____ when both denture base and denture teeth need work
_____ when at least 2mm is present under denture base OR indirect retainer lifts 2mm+
Remake
Reline
When should you reline the denture base?
- when at least 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, & lateral incisors, disclude the posterior teeth when the mandible moves in:
protrusion
Contacts between posterior teeth during excursive movements are considered _____ that can create damaging effects the teeth & periodontium
interferences
With anterior guidance, describe what should occur with the posterior teeth:
The 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 damaged 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 & relined
-good esthetics
-attachment to framework by lattice or mesh
Polymethyl methacrylate (PMMA)
_____ is the most common material to sue for the denture base
PMMA
What type of material would you use in distal extension cases?
PMMA
What type of joint is used with PMMA? Describe:
Butt joint (90 degrees) with major & minor connector
Can you reline a PMMA base?
yes
Advantages of acrylic resin bases (PMMA) include: (3)
- ability to reline the base as the supporting tissues change
- esthetically superior to metal bases
- ease of repair
Disadvantages of acrylic resin bases (PMMA) include: (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?
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
Corrections:
a) PIP means PRESSURE indicating paste
b) Should be put on INTAGLIO surfaces
c) Should be put in SMALL amounts
Checks soft tissue impingement during framework adjustment step:
PIP
PIP is placed on ____ surfaces 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 a circlet:
undercut OPPOSITE of edentulous side
An undercut adjacent to the edentulous side means no:
circlet
For adjusting retentive clasps as a general rule, at the tine of insertion _______ retention should be used
slightly less than maximum
Only the _____ should be used when adjusting a half round cast circumferential clasp
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 alot of inter arch space, what material should be used for the denture base?
metal
Metal bases can not be relined so they are generally not used for:
tooth-tissue borne RPDs or in areas where teeth have been removed in 12 months
Why are metal bases not used for teeth have been removed within twelve months?
resorption will still be occurring at an increased rate, and relining will usually ve required
T/F: All distal extension cases require clinical remount. All class III 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?
Co-Cr
Why is Co-Cr used more than Ni-Cr:
Due to nickel allergy
Possibly causes of failure of chromium-cobalt alloys include:
- cold-working
- shrinkage-porosity
- low percent elongation
- excessive carbon in the alloy
Cause of a chromium cobalt failure that reduces the percentage of elongation that causes a decrease in hardness:
cold-working
Cause of a chromium cobalt failure due to the alloys shrinking approximately 2.3% resulting in porosity:
Shrinkage porosity
Cause of a 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 cast
-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 & residual ridge (in distal extension cases)
What do you need for a clinical remount?
Interocclusal record (jaw relation)
Clinical remounting procedure:
- facebow preservation
- pickup impression
- block out undercuts
- remount cast and interocclusal record
- articulate
Describe a pickup impression (used in clinical remount)
when you insert an RPD in the mouth and take an impression, so that the impression picks up the RPD and 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 & stress distribution
A major connector can be made more rigid by:
using a more rigid alloy (chromium-cobalt = most rigid)
Chromium-cobalt alloys are _____ in comparison to gold or palladium alloys
more rigid
Chromium-cobalt alloys stiffness can be overcome by including:
wrought-wire retentive elements in their framework
____ alloys are approximately twice as flexible as _____ alloys
gold alloys; chromium-cobalt alloys (PTQ)
Kellys combination syndrome would present as:
Lack of osseous tissue in the anterior maxilla
What does NOT describe Kelly 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
True; 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 tootg
-1/2 distance between the cusp tips
With a guide plane, the normal tooth contour should be maintained:
BL
T/F: Gingival margin to superior border of lingual bar is 3-4mm. Measure the distance on the cast, not on the mouth.
First statement true; second 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
- compensates for casting inaccuracies
- displaces soft tissue, preventing 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- 1mm deep and 1.5 mm wide; feathers out to noting 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 denture
- poor oral hygeine
- leaving dentures in 24 hours a day
Treatment of papillary hyperplasia includes:
- educate patient on oral hygeine
- 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 & middle 1/3 of incisors
False- near 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
Positive 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 enameloplasty, one cannot have the changes necessary for the abutment teeth without cutting into the dentin
d) all of the above are true
d) all of the above are true
Indirect retainers have all of the following characteristics except:
Its a DO rest on a posterior abutment
(we want as far forward as possible so use an MO)
Hyperplastic 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)
