A STEP-BY-STEP CUSPID SLOT PREPARATION

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

Step 2. Removal of previous restoration and caries is accomplished.

Step 3. With a #169L bur a hollow ground or concave form is made in a labial lingual motion on the distal of a cuspid. This hollow ground forms the labial, lingual, and gingival extent of the cavity preparation. The axial depth at the deepest portion of the hollow ground at the gingival is between 1.2 to 1.5 mm. The drawn is made at the expense of the labial and axial walls. The gingival floor may slightly slope incisally at the labial. The line of draw is toward the lingual.

Step 4. With the same bur the axial wall from its deepest point axially is extended laterally to form the 'ears' of the preparation or give an hourglass appearance to the preparation. The proximal walls will be in two planes.

Step 5. With one end of the #45S off-angle chisel one half of the axial proximal line angle is formed on the labial. With the other end of the #45S off- angle chisel one half of the axial proximal line angle is formed on the lingual.

Step 6. With the regular #233 gingival margin trimmer, an internal bevel of even depth is placed in the dentin at the gingival to form an acute gingival axial line angle.

Step 7. With the #44S off-angle chisel the other half of the proximal axial line angles are formed. The instrument is used also to smooth the axial wall and sharpen the gingival and proximal axial line angles.

Step 8. With the #232 Tucker gingival margin trimmer an even external bevel is placed at the gingival. The bevel should be .5 to .75mm wide.

Step 9. A # 55 straight fissure bur is used to place a bevel on the lingual to help funnel the inlay into the preparation at seating, to remove any loose and unsupported enamel rods and to remove the hourglass appearance of the preparation.