LECTURE 14: SUPPORT FOR THE DISTAL EXTENSION DENTURE BASE Flashcards
does not have the advantage of total tooth support
DISTAL EXTENSION RPD
→ dependent on residual ridge for support, stability, and retention
DISTAL EXTENSION RPD
indirect retention is needed to avoid lifting away from ridge
DISTAL EXTENSION RPD
Which factor primarily affects the support of a distal extension base by providing a stable foundation?
• A. Contour and quality of the residual ridge
• B. Type of impression material used
• C. Occlusal height
• D. Position of the adjacent teeth
A
What is the significance of the extent of residual ridge coverage by the denture base in supporting a distal extension?
• A. It provides aesthetic appeal only.
• B. It enhances stability and support for the denture.
• C. It affects only the comfort, not the support.
• D. It is unrelated to support.
B
How does the accuracy of impression registration impact the support of a distal extension base?
• A. It has no impact on support.
• B. It affects the fit and stability of the denture base.
• C. It only affects the color of the denture.
• D. It affects only the durability of the denture material.
B
Which of the following factors involves creating a proper, tight fit for the denture base to enhance support?
• A. Type of impression material used
• B. Accuracy of the fit of the denture base
• C. Design of the denture framework
• D. Residual ridge quality
B
Why is the design of the removable partial denture framework important for distal extension support?
• A. It determines the color of the denture.
• B. It has no effect on denture support.
• C. It affects the stability and support of the denture.
• D. It only affects the comfort of the denture.
C
What role does total occlusal load play in supporting a distal extension base?
• A. It only affects the appearance of the denture.
• B. It determines the color of the denture material.
• C. It has no influence on support.
• D. It impacts the pressure and distribution on the denture base.
D
broad
A. Contour (Crest)
B. Quality (Connective Tissue)
A
rounded
A. Contour (Crest)
B. Quality (Connective Tissue)
A
high vertical slopes
A. Contour (Crest)
B. Quality (Connective Tissue)
A
→ firm
→ dense
A. Contour (Crest)
B. Quality (Connective Tissue)
B
fibrous
A. Contour (Crest)
B. Quality (Connective Tissue)
B
Pre-extraction
A. Order 1
B. 2
C. 3
D. 4
E. T
F. 6
A
Post-extraction
A. Order 1
B. 2
C. 3
D. 4
E. T
F. 6
B
High, well-rounded
A. Order 1
B. 2
C. 3
D. 4
E. T
F. 6
C
Knife-edge
A. Order 1
B. 2
C. 3
D. 4
E. T
F. 6
D
Low, well-rounded
A. Order 1
B. 2
C. 3
D. 4
E. 5
F. 6
E
Depressed
A. Order 1
B. 2
C. 3
D. 4
E. 5
F. 6
F
T/f
crest of bony mandibular ridge is cancellous
T
T/f
loss of firm mucosa over residual ridge after tooth extraction
T
T/f
buccal shelf region is better suited for secondary stress-bearing role
F
buccal shelf region is better suited for primary stress-bearing role
The tissues covering the crest of the maxillary residual ridge must be less ____ than the tissues that cover palatal areas, or relief of palatal tissues must be provided in the denture bases or for palatal major connectors
displaceable
T!f
The gum on the upper ridge should be firmer than the roof of the mouth. This way, the dentures stay stable.
T
T(/f
the broader the residual ridge coverage, the greater is the distribution of the load, which results in less load per unit area
T
not supporting occlusal load
A. Anatomic Form
B. Functional Form
A
supporting load
A. Anatomic Form
B. Functional Form
B
most physiologic form for denture suppor
A. Anatomic Form
B. Functional Form
A
When making dentures, the shape of the gum ridge (the area where teeth used to be) can look different depending on how it’s measured. When some pressure is applied-like from biting, pushing with a finger, or using a custom tray–the ridge shape under that load is called the
A. Anatomic Form
B. Functional Form
B
The difference between these forms depends on how thick or soft the gum tissue is and how much pressure is put on it. To make dentures that fit well, some methods record this “functional form” to capture how the ridge behaves under normal chewing or speaking pressure. This approach, called a___
functional impression
ensures the denture base fits better under real-life conditions
functional impression
requirements of distributed stress denture:
o positive-occlusal rests
o rigid and nonflexible framework
o indirect retainers
o well-adapted and broad coverage bases
Steffel’s categories of managing distal extension RPDs:
o stress-breakers or resilient equalizers
o physiologic basing
o stress distribution
T/f
distal extension is enhanced by close contact of tissue surface and residual ridge tissue
T
T/f
denture base must be related to the RPD framework as basal seat tissues to the abutment teeth when impression was made
T
the greatest movement takes place at the most posterior extent of the denture base, where in mandi and maxi?
Mn = retromolar pad
Mx = tuberosity
___ have suggested that moving rotational axis from a disto-occlusal rest to a more anterior location, more of the residual ridge receives vertically directed occlusal forces to support the denture base.
Steffel and Kratochvil
T/f
patients with distal extension removable partial dentures generally orient the food bolus over natural teeth rather than prosthetic teeth
T
T/f
the reduction of the size of the occlusal table reduces the vertical and horizontal forces that act on the removable partial dentures and lessens the stress on the abutment teeth and supporting tissues
T
T/f
the objective of any functional impression technique is to provide maximum support for the RPD base
T
ANATOMIC FORM IMPRESSION
(1) Anatomic Form Impression
(2) Rest and Base Fit
(3) Load Distribution
(4) Tissue Load Bearing
(5) Load Distribution Importance
(6) One-Stage Impression Risks
(7) Individualized Impression Tray
(8) Reline Considerations
(9) Distribution of Masticatory Load
impression requirements for providing adequate support to the distal extension RPD base:
o records and relates the supporting soft tissue under some loading
o distributes the load over as large an area as possible
T/f
SELECTIVE TISSUE PLACEMENT IMPRESSION METHOD
the tissues in the back of the mouth, near the vibrating line, can be slightly pushed down to create a good seal for the upper denture without causing harm
T
T/f
the framework fitted to the teeth while soft tissue support is registered provides a means of coordinating both this means that before the trays are attached, the framework must be fitted in the mouth
T
used when the mucosa of the residual ridge feels uniformly firm
FUNCTIONAL IMPRESSION TECHNIQUE
→ captures the shape and position of the tissue while the patient bites down, simulating the effects of chewing forces
→ when this technique is applied to firm mucosa that doesn’t easily displace, it results in minimal movement of the prosthesis
FUNCTIONAL IMPRESSION TECHNIQUE
T/f
while the selective pressure technique can be used for various types of residual ridges because it adapts to different mucosal conditions, the functional impression technique is more limited and best suited for uniformly firm ridge consistency
T
A
