7/8ths CROWN PREPARATION

Step 1. Anesthetic is administered and an extra heavy dam is placed.

Step 2. Removal of previous restoration and caries is accomplished. Check for cracks in the dentin and under the remaining cusps.

Step 3. A film of calcium hydroxide is placed over the pulpal and axial walls with a small cotton pellet and then retention potholes are placed with a1/2 round bur, if needed.

Step 4. Composite 'block-out' material is placed in cavity preparation and missing tooth structure. A matrix band may be used.

Step 5. Using a #57 straight fissure bur, reduce the occlusal surface flat in a mesial distal direction but parallel to the cusp inclines in a buccal lingual direction. If the buccal cusp is strong, it may not necessarily need to be covered. An inlay type wall may be placed instead.

Step 6. Using a #860-012 coarse diamond to break the proximal contacts, hollow grind the mesial proximal for resistance form extending the mesial buccal margin somewhat parallel to the contours of the adjacent teeth for esthetics. A #860-014 coarse diamond may be used on molars or area permitting the passing of a thicker diamond.

Step 7. The #869-012 diamond continues around the distal to form a definite wall on the buccal but distal to the height of contour of the tooth. The #860-014 can be used for molars and lingual of bicuspids The lingual and buccal margins need to be blended with the proximals.

Step 8. A #42S off-angle is used to form a sharp distal proximal line angle and plane the cavosurface margin on the distal.

Step 9. A counterbevel is placed on the working cusp if needed and the non-working cusp can be covered using a one plane wall for esthetics. The occlusal buccal margin of the non working cusp is disced lightly with a fine cuttle disc to remove any fragile enamel rods. This is usually on the maxillary arch.