|
Not Suitable: Tangential Preperation and Shoulder Preperation with Bevelled Edge
The preparation guidelines for Ceron restorations are geared towards the known recommendations for all-ceramic systems. Accordingly, the tangential preparation and preparation of a shoulder with a bevel are not suitable for zirconia restorations, because both preparation forms result in margins that drain off too thinly and hold the risk of fracture.
Recommended: Chamfer, Shoulder with Rounded Axio-Cervical Line Angle
The following preparation forms are suitable:
- Pronounced chamfer
- Shoulder preperation with rounded axio-cervical
line angle
To efficiently perform all-ceramic preparations in the anterior and posterior region, a preperation set comprising six diamond instruments was assembled( Ergo Prep Set, 4394, Gebr. Brasseler, Lemgo).
Cylindrical diamond instruments with a rounded tip (e.g. 8951KR314.014, Gebr. Brasseler, Lemgo) are especially suitable for the shoulder preparation with a rounded axio-cervical angle.
Circular Cutting Depth 1.0mm
The use of rotary instruments with an average grit size of 30um is recommended for finishing the preparation. The minimum wall thickness of the cervical region for veneering is 0.6mm, meaning that a circular marginal cutting depth of 1.0mm should be the aim.
|
 |
 |
