1(a) Prep a trough at the mesial marginal ridge AT LEAST the COMPLETE thickness of the EZPrep 001 donut bur. (The EZPrep 001 bur is 1.5mm thick.) Repeat at the distal marginal ridge.
1(b) Prep and blend the remaining center of the occlusal table that remains between the mesial and distal depth cuts to create a uniform occlusal reduction.
If six-year molars have not erupted, go back and prep the distal half of the occlusal table of the second primary molars slightly more (up to 2mm). This adjustment will reduce the chance of the second molars’ occlusion being slightly high, particularly when doing crowns on opposing second molars.
Keeping the bur perpendicular to the occlusal table, use the EZPrep 002 bur to create a chamfer margin at the gum line equal to the full thickness of the bur tip. (The EZPrep 002 bur tip is 0.85mm thick.) This AXIAL DEPTH CUT at the margin will automatically create the right amount of axial reduction elsewhere (0.85—1.5mm)—about the thickness of the EZPrep 002 chamfer bur.
The taper of the bur provides adequate prep taper. Do not additionally taper the prep. Avoiding any additional taper will minimize the chance of pulp exposure.
A chamfer margin the thickness of the EZPrep 002 chamfer bur must be visible at the tissue level all the way around the tooth. This is your Axial Depth Cut. If this margin is not visible, go back and repeat Step 2.
3(a) With the EZ-Prep 004 flame bur, remove the chamfer margin at the tissue level. Keep the bur parallel to the long axis of the tooth. To minimize tissue trauma, do not go all the way subgingivally yet. Begin at 0.5mm subgingivally and go slightly deeper subgingivally with each pass. This technique will minimize trauma to the tissue, thus reducing gingival bleeding.
3(b) Once the chamfer margin is gone, extend the tip of the bur the full 2mm subgingivally. While hugging the bur axially along the root surface, make three circumferential passes. All of the chamfer margin should be gone, leaving a smooth transition from the root, past the CEJ, to the coronal tooth.
The buccal bulge must be completely removed to allow for a passive fit. In younger patients, this tooth structure may be hiding below the tissue line. Therefore, it is essential to extend the tip of the EZPrep 004 bur 2.0mm subgingivally.
Go back and check the mesio-buccal of the first molars and the disto-lingual of the second molars as these are commonly under-reduced areas.
Watch for these areas as they are the most underprepared.
All of the chamfer margin should be gone, leaving a smooth transition from the root, past the CEJ, to the coronal tooth. Verify completion of this step by using an explorer (or EZPrep 004 bur tip) going from root to tooth ALL the way around the preparation. If any chamfer or labial bulge remains, go back and remove them with the EZPrep 004 flame bur.
