A STEP-BY-STEP PROCEDURE FOR FERRIER CLASS V CAVITY PREPARATION

Step 1. A line is scribed on the tooth with a thin edged wheel diamond parallel to the plane of occlusion.

Step 2. After the administration of anesthetic and the placement of extra heavy rubber dam, the appropriate #212 retractor is placed, with the jaw parallel to the scribed line. The retractor is supported on the lingual with a finger while it is being stabilized with red compound. Excess compound can be trimmed with a gold knife.

Step 3. The end-cutting portion of a #34 carbide or steel bur in a straight handpiece is used to form the gingival wall parallel to the jaw of the retractor. Keep the gingival wall narrow in a mesial distal direction. A #55 bur in the high speed can be used to remove the bulk of enamel in those teeth where it is present - usually cuspids.

Step 4. The end-cutting portion of the #34 bur is used to cut and flare the proximal walls and form sharp cavosurface line angles at the gingival and occlusal or incisal. The depth of each wall is approximately 1 mm. The proximal walls often parallel the dam.

Step 5. The side-cutting portion of the #34 bur is used to form the occlusal or incisal wall parallel with the gingival and initiate the acute axiogingival line angle. In heavy enamel a 1/2 inch medium garnet disc in the slow speed contra-angle or a fine diamond disc can be used to straighten the incisal or occlusal wall.

Step 6. Use the #21 hoe to remove bulk of tooth structure not removed with the bur, cutting from the cavosurface to the axial wall. This keeps the walls straight and defines the internal line angles. Scrape and flatten the axial wall.

Step 7. Use the #11 1/2 or #15 width Wedelstaedt chisel to refine all internal line angles, proximal and gingival cavosurface outline and to plane the axial walls.

Step 8. A 1\2 inch medium garnet disc or a fine diamond disc in a contra- angle handpiece can be used to straighten the middle 2/3 of the occlusal or incisal cavosurface margin.

Step 9. Use the #20 width Wedelstaedt chisel to refine the occlusal or incisal cavosurface out-line and the proximal cavosurface line angles.

Step 10. Use the #23 hoe to refine the gingival axial retention.

Step 11. Using light strokes and a sharp #11 1/2 or #15 width Wedelstaedt chisel, polish the axial wall in an up and down and a back and forth direction.

Step 12. Use the #34-35 angle former to refine the internal point angles by starting from the cavosurface line angles and working down to the axial wall.

Note: Like the inlay preparation, the foil preparation outline is defined by the bur. The bulk of tooth structure is also removed by the bur. Refining the final preparation is done with hand instruments.