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Shade Selection
Recommended Shade Guides: Ivoclar Chromascop®.
General Considerations
- Ensure even reduction of the anatomic form.
- Avoid sharp internal edges, angles and undercuts. Create rounded internal
line and point angles, particularly at the linguoincisal line angle.
- Create a shoulder preparation of 1.2 mm at a 90-110º angle. Maintain
shoulder preparation with butt joint margins. Avoid tapered margins,
feathered edges and bevelled margins.
ANTERIOR
CROWN PREPARATION
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- Reduce lingual surface 1.5 mm at the area of centric contact
(not less than 1.0 mm) and 0.8 to 1.0 mm along the remaining lingual
surface.
- Incorporate taper of 8 to 10 degrees (never more than 12º)
- Tooth preparation length should reflect a 1.5 to 2.0 mm occlusal
(incisal) reduction.
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VENEER
PREPARATION
| Uniform
Facial Preparation |
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| A
medium grit, round-ended, diamond bur is used to remove a uniform
thickness of facial enamel by joining the depth-cut grooves. |
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Join
the depth grooves in three places by angling the diamond bur to the
corresponding gingival, middle or incisal plane of the tooth. |
| Chamfer
Margins |
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Interproximal
Extension |
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| Correct
preparation of the chamfer margins interproximally allows appropriate
bulk of porcelain. |
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Using
the same round-ended diamond bur, the interproximal preparation is
extended from the gingival chamfer margin into the proximal space.
NOTE: Eliminate all discolored enamel in the interproximal. |
| Incisal
Preparation |
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Lingual
Reduction to Increase Length |
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The diamond
bur is angled to bevel back the incisal edge.
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The diamond
bur is angled to eliminate undercuts and establish a deep chamfer
on the lingual aspect of the preparation to ensure a passive fit.
The incisal edge should be rounded. Avoid all sharp angles.
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POSTERIOR
CROWN PREPARATION
INLAYS/ONLAYS
Inlay Preparation
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- Avoid sharp internal line angles and undercuts.
- Smooth prep walls and trim excess lining material with finishing
diamond or bur
- Do not include undercuts
- Create a 5º to 15º divergence in the proximal walls from the
floor to the occlusal margin of the preparation.
- Ensure all walls end in a butt margin.
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Onlay Preparation
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- Avoid sharp internal line angles and undercuts.
- With onlays, cuspal reduction of a minimum of 1.5 mm is required.
- Smooth prep walls and trim excess lining material with finishing
diamond or bur.
- Do not include undercuts.
- Create a 5º to 15º divergence in the proximal walls from the
floor to the occlusal margin of the preparation.
- Ensure all walls end in a butt margin.
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Reprinted with
the permission of Ivoclar North America. IPS Empress is a registered trademark
of Ivoclar North America, Inc.
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to IPS Empress product page
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