Exam 2 Flashcards
What other material do we used in restorative dentistry that undergoes a crystallization reaction?
Amalgam
What do you use for MIP if hand articulation is not possible (i.e. there is not enough teeth)?
Transfer copings
Over-contoured crowns contribute to:
periodontal disease
A posterior pontic may be up to __% narrower than the tooth it is replacing to reduce the occlusal load.
20%
__% of all pontic sites show clinical inflammation.
33%
__% of all pontic sites show some inflammatory response under the bridge.
95%
Why do we need to use more water in plaster compared to Type IV gypsum?
The shape of the particles is more irregular in type II so more water sorption
What is the minimum distance between the crown margin and the alveolar crest?
2.6 mm (Margin ends 0.5 mm coronal to epithelial attachment + 2.1 mm biological width)
What kind of forces does orthodontic tooth movement utilize?
Intermittent
What can result from excessive orthodontic forces?
Root resorption
Is trauma from occlusion reversible?
Yes
Can occlusal trauma cause periodontitis?
Yes
Too much occlusal pressure results in:
- hyalinization
- vascular changes
- bone resorption
Too much tension results in:
- Widening of PDL
- Hemorrhage
- Tearing of PDL
- Resorption
What area of the periodontist is most susceptible to injury from excessive occlusal forces?
Furcation
When patient has both inflammation and occlusal trauma, which do you treat first?
Inflammation
What type of connector would we use for a small unit bridge?
Rigid
Overextension of Wax Pattern Fabrication can lead to:
over contouring
open margins
broken margins
incomplete seating of castings
Under-extension of Wax Pattern Fabrication can lead to:
short margin under contour tooth sensitivity (because of exposed tubules)
What are the two common accelerators?
Salt
Gypsum powder
Gypsum:
Type 2 water to powder ratio:
Type 3 water to powder ratio:
Type 4 water to powder ratio:
2 = 45ml/100g 3 = 35ml/100g 4 = 22ml/100g
What do you use to verify centric relation?
Wax wafer and split cast technique
What is the most accurate way to measure MIP?
Hand articulation
What is the most accurate way to measure CR?
Bilateral manipulation
When there aren’t enough teeth, what can we do to measure MIP?
Resin Transfer Coping
Major embrasures for posterior teeth?
Lingual, gingival
Minor embrasures for posterior teeth?
Occlusal, buccal
Porcelain component = __mm ideal thickness (uniform)
Cast metal component = __ mm minimal thickness (variable)
1 mm
- 5 mm
* porcelain should be thicker to hide the metal
Addition reaction:
addition silicone
Condensation reaction:
polysulfide
condensation silicone
Ring-opening reaction:
polyether
What is the base and catalyst of polysulfide?
Base = polysulfide Catalyst = lead dioxide
Byproduct of polysulfide?
Water
Activator for thermo acrylics?
heat
Initiator for thermo acrylics?
Benzoyl peroxide
Self-cured resins activator?
tertiary amines
