Vsmile Zirconia Crowns Preparation Guidelines

Why tooth preparation design is important 

· Smooth edges result in lower stress on the crown. This lower stress decreases the percentage of fractures occurring. 

· Ceramic restorations require a passive fit. 

· Uniform reduction results in excellent ceramic strength.  

· Sufficient reduction leads to the best aesthetic results. 

· Digital scanners read smoother preparations with more accuracy. 

Preparation guidelines for an anterior zirconia crown

· When prepping a tooth for an anterior Zirconia crown, you will need to ensure sufficient room for the wall thickness to have a minimum of 0.3 mm and ideally between 1.0 mm and 1.5 mm, or 1.8 to 2.0 mm incisal reduction.

· There should be a visible and continuous circumferential chamfer with at least a 0.5 mm reduction at the gingival margin.

· The horizontal and vertical preparation of the tooth should have an angle of approximately 5°, and a bevel is not advisable.

· All the incisal edges should be rounded, and the lingual aspect of the anterior should be reduced with a football diamond to create a concave lingual. 

Preparation guidelines for a posterior zirconia crown

· When prepping a tooth for a posterior Zirconia crown, you will need to ensure sufficient room for the wall thickness to have a minimum of 0.5 mm and ideally between 1 mm and 1.5 mm or 1.5 to 2 mm occlusal reduction.

· The prep should be tapered between 4°and 8°. It will also need to have a visible and continuous circumferential chamfer, and a reduction of at least 0.5 mm is required at the gingival margin.

· Just as with the preparation for an anterior crown, a bevel is not recommended. Ensure that all occlusal edges should be rounded.

· Shoulder and Chamfer preparations are ideal for zirconia. Feather Edge preparations are not recommended but can be acceptable for full-Zirconia crowns. Check with your dental laboratory to see if their fabrication process will allow for this prep form.