Initial Depth

This is with the use of 330 bur establishing 1.5mm depth of the cavity preparation. This does not translate to 1.5mm depth all throughout the area but it is the measurement of the minimum bulk of the restoration.

Placing the punch cut on the central groove and establishing a 1.5mm depth will be your guide to make the outline form of the cavity, extending to every grooves and fissures. The walls of the cavity, will roughly measure to 1.75-2mm.

By providing the initial depth, you will less likely to perform various depths throughout the cavity. Also, the restorative material will have enough bulk to withstand fractures.