Shade Selection
Recommended Shade Guides: Vita Lumin or Vita 3D-Master Shade Guide.

GENERAL CONSIDERATIONS

Technique Tips

• Ensure even reduction of the anatomic form.
• Provide enough room for the ceramic to allow adequate strength.
• Sharp transitions and sharp internal edges/line angles or undercuts MUST be avoided.
• Margins should have a pronounced chamfer or shoulder with butt joint margins. Avoid tapered margins, feathered edges or bevelled shoulders.
• Ensure there is an adequate path of insertion.

Suggested Margin Preparation

Shoulder with rounded axio-cervical line angle, uniform circular ablation.		Chamfer preparation (with reduced mechanical support of the crown). Particularly used with reduced substructure (e.g., after repeated crowning).

Common Preparation Errors

1. Insufficiently defined and finished preparation margins.

• Uneven preparation limit ("gutter" preparation, vertical unevenness).
• Irregular marginal reduction of layers (horizontal unevenness).
• Wrong shape of preparation limit.
• Unnecessarily deep subgingival preparation.
• Preparation in root dentin.

2. Poorly controlled tooth reduction.

• Excessive reduction, especially in the upper anterior teeth (vestibular) and premolars.
• Excessive incisal/occlusal reduction causing reduced retention and stability.
• Insufficient reduction at the palatal side of the upper anterior teeth (malfunction occlusion).
• Excessive taper.

Incorrect preparation of the labial surface: Preparation in one plane; therefore insufficient reduction of substance. Fracture of the crown may result due to insufficient wall thickness of the crown.		Incorrect preparation of the labial surface, risk of damage to the pulp.

ANTERIOR CROWN PREPARATION

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.

	Original position of teeth.
	Preferred final position of teeth.
	Actual preparation required to achieve preferred final position of teeth.

POSTERIOR CROWN PREPARATION

INLAYS/ONLAYS

Inlay Preparation

Technique Tips

• Ensure all walls end in a butt margin. No flared or feather edge margins.
• Enamel surfaces created by parallel preparation are generally sufficient for acid etching with flat cusps; a diverging preparation helps optimize acid etching of the enamel.
  

 

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.

Onlay Preparation

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.

Posterior or Anterior INLAY BRIDGE PREPARATION

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