Class I,V, and Buccal pit amalgam preparations Flashcards
____ is an alloy of silver, copper, tin, and zinc mixed with mercury to form an alloy that can be packed into a dental preparation, and which will set up to form a solid restoration
Amalgam
Amalgam has ____ compressive strength and ____ tensile strength which means it is brittle in small bulk
High compressive strength; low tensile strength
Amalgam is _____ to moisture contamination during placement. Water reacts with the zinc in the amalgam and causes an eventual expansion of the alloy out of the prep
sensitive to moisture contamination
T/F: You can scrape off the top contaminated layer of an amalgam and keep packing the amalgam
True
Does amalgam corrode?
Yes
What does modern alloys have in them to minimize the corrosion?
High Copper content
Amalgam creates and ______ a seal between itself and the tooth because of the oxides formed; they expand and fill tiny voids and prevent microleakage
regenerates
Poor esthetics, need for good mercury hygiene, need for full depth tooth prep due to weakness in small bulk, doesn’t bond to tooth structure, thermal conductor making necessary the use of a liner or base to prevent post-op sensitivity, may ditch at the margins collecting plaque are disadvantages of ____
Amalgam
Less difficult to use in area where moisture is hard to control, high wear resistance and compressive strength, can be placed in less time than other options, cost less, long-lasting, regenerates its seal, less prone to recurrent decay than bonded composite resin restorations are advantages of _____
amalgam
Does there need to be a means for isolation for amalgams?
Yes
What are the 3 things that you gain from isolation during an amalgam restoration?
Visibility, access, and moisture control
____ attaches to high speed evacuation line, retracts tongue; has a disposable flexible vinyl component with a reusable valve adapter
Isolite/Isovac system
All _____ enamel must be removed from all margins
Undermined
Should there ever be acute angles on the tooth?
No
How deep should preps be for amalgams and into what layer of tooth?
.2 to .5 thru the enamel to dentin
____ is a term that refers to what holds a restoration in a tooth; amalgams don’t bond to tooth structure
Retention Form
How are smaller amalgams held in place?
Converging walls or retention grooves
_____ is a term that refers to element in the design that will help both restoration and tooth resist fracturing
Resistance Form
Does maintaining tooth structure preserve resistance form?
Yes
Having some areas on the floor of a multi-surface preparation that are perpendicular to occlusal forces make the RESTORATION _____ likely to fracture
less
____ internal line angles on a preparation (at least a little bit) make the TOOTHless likely to fracture.
Rounding
Smoothly _____ outline forms make the RESTORATION less likely to fracture.
rounding
Is a buccal pit restoration a class I or V?
Class I
_____ is a class I restoration because it occurs in the occlusal 2/3 of a molar tooth and it restores a development pit
Buccal pit amalgam
