Denture Midterm Flashcards
(207 cards)
What is the most desirable arch form for dentures?
Square arch; tapering is least desirable
Which arch size has the smallest margin for error
during impression making: large or small?
Small
What determines the amount of denture bearing area for
support of complete or tooth-tissue supported RPD?
Edentulous ridge width
What does edentulous ridge height provide?
Vertical walls that help the complete denture resist
movement horizontally
Is edentulous ridge height as important for horizontal
stability in RPD’s as it is in dentures?
No, RPD has framework to aide in resistance of
horizontal displacemen
What should be done to the pour up of an impression
of a tall, thin edentulous ridge before removing it from
the custom tray?
Soak in hot water to soften wax and undercut
blockout to decrease risk of breaking cast removmign
the impression
In determining the radiographic ridge height, the value of B determined by what?
The inferior border of mandible to crest of edentulous ridge
In determining the radiographic ridge height, what is the value of A determined by?
The inferior border of mandible to top of the mental foramen
What is the formula for calculating the percent bone remaining from the above two variables?
(B/3A)x100
If teeth are in the mandible, what are the variables and the formula for determining the percent bone remaining in areas adjacent to natural teeth?
R=root apex to crest of alveolar bone
C=root apex to CEJ
(R/C)x100
What are 4 categories of edentulous ridge shape?
U-shaped
V-shaped
Bulbous
Flat
What is another classification that is reserved for the mandibular posterior ridge?
Concave
What area of the mandible is the theoretical primary denture bearing area for a mandibular complete denture?
Buccal shelf
When classifying the height of muscle attachment and frena attachment versus the edentulous ridge, what does a high versus low attachment delineate?
“High” indicates the muscle or frena moves within 1-2mm of the crest of the edentulous ridge
“Low” indicates the muscle or frena moves 5mm or
greater from the crest of the edentulous ridge
What is indicated if the crest of the edentulous ridge moves with the normal movements of the vestibule?
Surgery: vestibuloplasty, ridge augmentation, mucosal or skin graft
Which side of the mandibular denture base length is particularly critical to the success of the mandibular denture?
Lingual border
Which ridge has more denture bearing area?
Maxillary
Why is the ideal palatal vault form for a maxillary complete denture flat with moderate depth, fairly tall edentulous ridges with parallel sides, broad flat crest, and fairly steeply inclined rugae?
Vault shape gives max area perpendicular to occlusal forces for dissipation
Ridge height prohibits horizontal denture movement
Why is a deep palatal vault favorable for denture retention but difficult to obtain an accurate impression and cast?
Easy to trap air during impression
Why is an impression of the palate of inherently decreased accuracy?
Because material shrinks toward its bulk (i.e.toward the tray and away from palate as it sets)
What are 4 reasons complete dentures are beaded so they will contact the palate?
- Inaccurate impression because material shrinks toward its bulk
- Material falls away from palate due to gravity
- Dental stone slumps away from palate if the impression is poured and immediately inverted onto a base
- Plastic based distorts when removed from cast due to
strains from polymerization
A soft palate that flexes downward at an angle of 0-30 deg is what class?
Class I
A soft palate that flexes downward at an angle of30-60 deg is what class?
Class II
A soft palate that flexes downward at an angle of 60-90 deg is what class?
Class III