Flashcards in Exam 2: Retention,Resistance,Convenience Deck (26):
_______ form: Design features which lock or retain the restoration and prevent the restoration from coming out.
Class II amalgam: The internal walls (F/L) are slightly ______ or straight. Which 2 burs create this?
convergent....245 or 330
A ______ isthmus allows for greater convergence.
The ______ the isthmus the less the prep will converge, due to the enamel rods.
RETENTION GROOVES: are in ______, follow the ____, do NOT cut into the _____ wall!!! Placed into the _____ and ______ walls, use a _______ bur or the tip of a thin tapered diamond bur, should extend from the ______ floor to the _____ floor.
dentin...DEJ...axial (my issue!)..facial & lingual (again, NOT AXIAL!!)...1⁄4 round...gingival...pulpal
What was the % of bonding amalgam that worked over 5 years? (even though it DOES help with retention!)
53%..not too good dawg
What does adding a '+' in the prep surface notation mean?
a cusp is taken out with the prep (#19MOD+)
For really freaking big preps, you can increase retention with _____ and ______ to make an undercut. You can use the depth and width of a ____ bur, but watch out for the ____!!
slots and troughs....34 diamond...pulp!
For a CROWN PREP! We need at least __mm to retain a crown.
_______ form: Design features which help the restoration and tooth resist FRACTURING as a result of OCCLUSAL forces.
Resistance form: amalgam prep-need ATLEAST ___ mm depth in the central groove for adequate strength.
EXAM Q: The AXIAL thickness for your class II amalgam REQUIRES __mm for PM's and ___mm for molars!!!
1mm pm's....1.2mm molars
What is the #1 source for CUSP fracture?
What is the minimal isthmus width on a class I amalgam prep??
Effects of strain and fracture propagation are ________!!!!!
_______ expansion of the tooth and amalgam creates lots of internal strain on tooth structure.
We want ______ internal line angles!
Floors are ______ to the occlusal forces! Except the ______.
perpendicular...mand first pm
Over-converging our walls will create ______ enamel!
Having a 90 degree cavo-surface margin helps keep _____ to a minimum.
Having an '__' curve on our Class II amalgam prep helps us keep the triangular ridge!
The angle of departure needs to be ____ degrees (we do this with the hatchet.
The axio-pulpal line angle is ______ in our Class II preps. When do we need to make a bigger one of these?
beveled...Deep decay requires a bigger bevel
_______: Design features which make the procedure accessible and easier to be performed.
Is it ok to keep the prepped tooth in contact on our class II?
yes, like our aesthetic example