If your units are milling with missing margins or missing anatomy, a possible issue could be the Zeta Alignment.
The Zeta Alignment is the position of a unit inside a disc relative to its vertical position. The correct alignment should be calculated based off of its median. This is the midline of the unit, so that the unit is equal distance from either side of the disc.
Correct Zeta Alignment should look like this. This is a proper alignment to the median.
If a unit is mis-aligned to its Maximum Zeta, it will look like this. This would result in a unit wiith missing margins.
If a unit is mis-aligned to its Minimum Zeta, it will look like this. This would result in a unit missing its occlusal anatomy.
To correct a mis-aligned Zeta Alignment
- Open SUM3D, and click the Zeta Align Button.
- Once clicked, the Alignment menu will display.
- To adjust the Zeta Alignment, change the Alignment Type field. Click the down arrow on the right of the Alignment type field to see the options.
- To return the units to the correct alignment, select Align the median Z, then Ok. This will correct the alignment of all units in the current disc.
The units will now be aligned correctly to the median of the teeth and will look like this.