Fixed Prosth and Prep Flashcards
For a prep for zirconia and gold, what type of prep should be performed?
Shoulder prep
For a prep for zirconia and gold, what should the axial angle be?
4 degrees
For a prep for zirconia and gold, what should the axial depth be?
1 mm
For a prep for zirconia and gold, what should the occlusal/incisal depth be?
1.5-2mm
For a prep for zirconia and gold, what should the lingual depth be?
as little as 0.5
For a prep for zirconia and gold, how much depth is taken off functional cusp?
1.5 mm
For a prep for zirconia and gold, how much depth is taken off non-functional cusp?
1.0 mm
The scope of _____ includes: Restoration of a single tooth or rehabilitation of entire occlusion•Improve patient’s comfort and masticatory ability•Maintain health and integrity of dental arches•Elevate patient’s self-image by restoring dento-facial harmony
Fixed prosth
Which material used in fixed prosth is a crystalline structure that is 100% dense, has a tetragonal base, and extremely fine grain size that yields high strength?
Zirconia
What aids us in evaluation of tooth structure removal, and when complete, can help us make a provisional restoration
vacuum formed matrix
What size is the plastic sheet used to make the vacuum formed matrix
.020 mm
You want to cut down the vacuum matrix to which teeth?
One mesial to one distal of the tooth being worked on
Do you trim the vacuum matrix at the free gingival margin?
No
How far gingival do you want to trim the matrix?
5-6mm
What is used to make a putty matrix to evaluate the tooth structure reduction?
PVS
Where do you cut the PVS putty matrix?
In the center of the tooth being prepped
What kind of burs are used for crown preps?
Diamond
Which diamond bur is wider? 3.14.021 or 3.14.016
.021
What does the green stripe on diamond bur mean?
Course
What does the red stripe on diamond bur mean?
Fine
Where should a groove be placed on the crown prep?
Facial
____ form resists movement in the lateral direction
Resistance form
_____ form resists removal of the crown itself
Retention form
Prevents restoration removal along the path of insertion or the long axis of the tooth preparation.•Resists sticky foods.
Retention
Prevents restoration dislodgement by apical or oblique forces.•Occlusal forces.
Resistance
The angle of convergence formed between 2 opposing prepared axial surfaces.
Total Occlusal Convergence (Taper)
What is the ideal total occlusal convergence?
6-10 degrees
What is the clinically acceptable total occlusal convergence?
10-20 degrees
Does an increase in length increase or decrease resistance?
Increases resistance
Does an decrease in length increase or decrease resistance?
Decreases resistance
An increase in ____ produces a lock to resist lateral forces and movement
Height
As the preparation ____ is increased the retention and resistance is increased.
length
For every 1 mm increase in preparation length, the retention and resistance form increases up to ____.
10%
The shorter the preparation, the ____ the taper must be.
lesser
The longer the preparation, the ____ the taper maybe.
greater
Is the arc or rotation larger for wider or narrower teeth?
Wider
Do wider or narrower teeth need to be more parallel to resist lateral forces/movement?
Wider
What is the minimum height that an incisor and premolar prep can be?
3 mm
What is the minimum height a molar can be?
4 mm
Thickness of partial veneer crowns (using high lucite porcelain) should have at least a thickness of _____ mm in stress bearing areas.
1.5-2.0 mm
_____ is explained by: retention is increased by limiting the number of paths along which a restoration can be removed from tooth preparation
Freedom of Displacement
Adding grooves limits the path of withdrawal to only 1 path which achieves _____ retention (greater or lesser)
Greater
What bur should be used to do the occlusal reduction?
.016 diamond (1mm)
At what angle should the .016 diamond bur be held to get the functional cusp bevel?
45 degree
The ____ line is a line that goes around the tooth that is about 0.3-0.5 mm; easy to form, adequately distinct, adequate bulk for rigidity, adequate depth for normal contours in an all-metal crown
Chamfer Finish line
To form the _____ , select a diamond that is 2x the desired depth (.3-.5mm) and place the rotating instrument into the tooth to 1/2 is diameter and move the instrument around tooth
Chamfer finish line
Place the bur in the _____ to determine the proper path to perform the axial reduction
Center of occlusal plane
What bur should you use for the axial reduction?
.021
A slight _____ avoids abrading adjacent teeth on the proximal reductions
Over tapering
Which bur should be used for the proximal reduction?
.016
What bur should be used to smooth the corners of prep?
Red stripe football diamond
____ is a principle of tooth prep that includes the chamfer line, more conservative so that less tooth is removed, shoulder line, modified shoulder; feather-knife edge
Marginal geometry
Should porcelain or gold fill the crevice?
No
____ is a marginal geometery principle that is used in metal ceramic margins and some all-ceramic crowns that is flat
Shoulder
____ is a marginal geometry principle Used primarily for porcelain fused to metal crowns; flatten with a hand instrument
Modified Shoulder
What is the marginal geometry principle that is contra-indicated? Causes overbulking
Feather/Knife edge
_____ features include limiting the path of withdrawal and shortening the rotational radius
Secondary features
_____ reduction like a functional cusp bevel provides Adequate occlusal/incisal clearance without excessive removal of tooth structure.•Anti-rotational effects for increased resistance. •Uniform restoration thickness.•Adequate room to reproduce physiologic contours and functional anatomy.•Adequate room for esthetics.
Morphologic reduction
Direct evaluation of parallelism and path of draw is done with what instrument?
Handpiece
Visual evaluation of parallelism and path of draw is done with what instrument?
Mouth mirror
The article shows evidence that crowns with grooves in the ____ axial walls show the greatest resistance form?
Proximal walls
