03: All Metal Crown Prep #30 Flashcards
What is the dimension of the Chamfer margin
0.5 mm
What is the depth of the Secondary Retention groove
Full depth of 170L bur
What is the dimension of the axial reduction?
0.5-1.0 mm
What is the dimension of the functional cusp bevel
1.5 mm tapers to 1.0 mm
What are the two types of morphologic occlusal reductions
Functional areas and non-functional areas
What is the dimension of the functional occlusal reduction
1.5 mm
What is the dimension of the non-functional occlusal reduction
1.0 mm
What steps should be taken before beginning?
Fabricate putty preparation
Reduction guide
Matrix
After getting the putty impression, what is the next step?
Identify M & D cusp tips prior to sectioning
After the putty preparation is sectioned, what else should be done before beginning preparation?
Verify and equilibrate articulation of dentoform
Evaluate occlusal contacts
What is the proper sequence for the all metal crown prep?
Occlusal Reduction functional cusp bevel Axial reduction Proximal reduction Secondary retention if needed Margination
What is Step 1 of the procedure
Occlusal reduction
What is true about the depth cuts of the occlusal reduction?
They typically follow the inclines of the tooth
Consider the planned restoration
For all metal crowns, what is the required clearance on functional areas?
1.5 mm clearance
What structures are considered functional areas?
Functional cusps
Central Groove
Functional inclines of Non-Functional cusps
How wide is the tapered diamond bur at the tip?
1.2 mm
What is Step 2 of the procedure?
Functional Cusp Bevel
What type of bur is used for the functional cusp bevel?
Round-end, course tapered diamond
What are three facts of the functional cusp bevel?
It completes the occlusal reduction
It re-aligns the functional cusps with the opposing central groove
It provides for a uniform 1.5 mm functional occlusal clearance
At what angle, relative to the long axis, is the bevel made?
45 degrees
What is Step 3 of the procedure?
Facial and Lingual Axial Reduction
What type of bur is used for the axial reduction?
Round-end taper diamond
Small chamfer tapered diamond
For all metal crowns, what is the adequate dimension of axial reduction?
0.5 - 1.0 mm
What two surfaces should be parallel?
Facio-lingual
Mesio-lingual
When should the path of draw be determined?
Prior to starting the axial wall preparation
What is the ideal taper TOC of opposing walls
6-10
What might be present in an INADEQUATE Axial Wall Reduction
Finish line not definite
Restoration will lack bulk needed for strength
May cause over-contoured restoration
What is Step 4 of the Procedure?
Proximal axial reduction
What burs are used for the Proximal axial reduction?
Needle chamfer diamong
Small chamfer diamond
Why is a TOC of up to 15 degrees allowed for the proximal axial reduction?
To avoid damage to the adjacent teeth
What is Step 5 of the Preparation?
Margination
What bur is used for margination?
Small chamfer tapered diamond
What is the dimension of the finish line chamfer?
0.5 mm light chamfer
What is a good way to estimate 0.5 mm?
1/2 the diameter of the small chamfer diamond bur
What qualities does a good chamfer posess?
Smooth
Continuous
Well-defined
What is Step 6 of the procedure?
Finishing Verify occlusal clearance Verify morphologic reduction Round occlusal-axial line angles Verify the draw
How do you verify the occlusal clearance?
Measure clearance with ball burnisher or other pre-measured instrument
Measure regisil placed b/w the prep and the opposing dentition
Measure putty matrix with perio probe
Measure the occlusal thickness of the provisional
What is the quality of a Rounded Occlusal-Axial line angle
Smooth preparation transitions
What bur is used to round the occlusal-axial line angles?
Small chamfer bur
What instruments are used to evaluate Parallelism and Path of Draw?
Direct: Handpiece
Visual: Mirror
