ACC preps Flashcards
what is the incisal edge reduction?
2.0mm
the width of an all-ceramic crown shoulder should be approximately ____mm
1.0
there needs to be at lease ___ mm of clearance between the prep and the opposing teeth when in occlusion
1.0mm
what does the axial first plane cut establish?
the path of placement/withdrawal for the crown
what is the purpose of the labial second plane?
provides a uniform thickness of porcelain over the labial surface
the _______ is approximately 1/2 the incise-cervical height of the labial surface after incisal reduction
labial 2nd plane
what will excessive angulation of the labial 2nd plane result in?
over-reduction and a thin incisal edge
what is the ideal convergence angle of the lingual 1st plane?
8 degree included angle
maxillary incisors are inclined nearly _____ degrees to the labial
30
the _____________ is 100 degrees to the outer surface of the tooth
cavosurface margin
what is the range of acceptable shoulder widths?
1.0-1.2 mm
how much is the labial (facial) plane reduced?
1.5mm
the lingual first plane is reduced ___ to ___mm
1.0 to 1.2mm
the lingual 2nd plane (concavity) must be reduced to allow ____mm clearance
1.0
how wide must the labial rounded shoulder be?
1.5mm
_________ line angles is critical in ACC preps
rounding
which burr is used for the incisal reduction?
256 burr
why is a 2.0mm incisal reduction needed?
for good esthetics
the shoulder should extend ___mm lingual to the proximal tooth contact area
1.0
the shoulder of an ACC prep should be ___mm from the gingiva
0.5
half mm above the gingiva
each labial guide groove should be placed to the full depth of what bur?
256 diamond burr
the lingual SECOND plane should be reduced with what burr
the 285 (football) burr
T/F: the lingual second plane of incisors are prepared flat or slightly concave, while canines have a double concavity
true
list the burrs, in order, that are used for inter-proximal reduction
1) 169L carbide
2) 242.6M diamond
3) 256.8M diamond
what bur is used to remove the “lip” on the cavosurface margin?
770 diamond
where is the “ideal” placement of the cervical margin?
.5mm incisal to the CEJ or the free gingiva (whichever is most coronal)
the appropriate path of insertion/withdrawal is 8 degrees from what?
8 degrees from parallel along the long axis of the tooth
what is the visual taper of the axial walls on an MCC prep?
6-8 degrees total
3-4 degrees per wall
the optimal lingual wall height is ___mm
2
