Preparation guidelines for zirconia crown.

Zirconia crown is a white solid ceramic glaze which combines metal strength with the aesthetic, tooth-like appeal of porcelain. Made from zirconium dioxide, zirconia crown preparation requires less time in comparison to other materials that can be shaped by a dentist and is durable. It can be bonded or cemented to the tooth and it is biocompatible because it won’t cause any adverse reactions on patients’ bodies. 

Here, are the proper preparation and guides for zirconia crown

• Anterior zirconia crowns preparation guidelines: Anterior zirconia crown will ensure sufficient room for the wall thickness which has a minimum of 0.5mm and at least between 1mm and 1.5 to 2 mm incisal reduction. The preparation should be phased between an angle of 4 and 8 degrees. It should be a visible and continuous circumferential chamfer with at least a 0.5 mm reduction at the gingival margin. If it is horizontal and vertical, preparation of the tooth must have an angle approx. 5 degree and a bevel is not certainly not advisable. In anterior zirconia crowns preparation all incisal edges should also be rounded.
• Posterior zirconia crowns preparation guidelines: While preparing a tooth for a posterior  zirconia crowns preparation, dentists need to make sure that there is enough room for the wall thickness to have a minimum of 0.5 mm and at least between 1 mm and 1.5 mm or 1.5 mm to 2 mm occlusal reduction. The preparation should be tapered between an angle of 4 degree to 8 degree and it will also need to have a visible and continuous circumferential chamfer and reduction of at least 0.5 mm is required for gingival margin. In the preparation guidelines for a posterior zirconia crown, a bevel should not be recommended and it also ensures that all occlusal edges should be rounded. 

Why do you need tooth preparation design?

Tooth preparation is essential for the fit to fixed prosthodontics. Lack of tooth preparation appears to be responsible for premature failures. Tooth preparation will preserve the tooth structure, marginal integrity and structural durability of the restoration. Tooth preparation design may take many forms and it is primarily dependent on the materials chosen and collar design for the final restoration. It is essential for successful laminate veneer treatment which has the advantage of controlling plaque. 

Tooth preparation design is needed because:

• Ceramic restoration is required in a passive fit.
• Digital scanners can read smoother preparation with more accuracy.
• Smooth edges can lead to lower stress on the crown. The lower stress will decrease the percentage of fractures occurring.
• Sufficient reduction leads to the best aesthetic results
• Uniform reduction results in an excellent ceramic strength.
• To provide rest seats.
• Establish guide surfaces.
• Modify unfavorable survey lines.
• To create retentive areas.