The prep is the design

Single-unit workflow on a real library mesh. Capstone is Universal #19 (FDI 36) — a mandibular left first molar with a scanned prep. #3 is the opposing maxillary prep.

Mandibular left first molar

Real prep mesh

Finish line

Margin trace

Auto-trace drops points on the cavosurface guess — close, not gospel. Grab a point and drag it onto the finish line you marked. Click the tooth to add one.

0 control points

Need more of the circumference

Path of insertion

Open Insertion or Undercuts. The teal arrow is the direction the crown will seat. Drag the slider to tilt it. The prep paints as you tilt:

Teal — surface faces the path (draw / mill).
Gold — nearly parallel. Retention is fading.
Red — undercut. The crown will not seat past it. Block it out (lose retention) or retitle the path.

0% of the wall above the margin is undercut

Mesial tilt0°Distal tilt

Below the margin is left dentin-colored — remainder of the tooth, not the restoration path. The white ring in this view is the finish line (teal/red join).

Order of operations

Inspect the scan.
Trim gingiva that is not the tooth.
Mark a closed margin.
Set path of insertion.
Block out undercuts.
Apply die spacer short of the margin.
Seat a library tooth.
Adapt contacts and occlusion.
Check thickness. Export.

Crown CAD lesson