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M1 step 6 of 6 · Fine diamond and sectioned putty index
Finish continuous chamfer and verify clearance with putty index
Finish one continuous chamfer with rounded line angles, then seat the sectioned putty index and read the gap over the prep.
Your last prep
No prep scored yet. Your first score is free with an account.
Score a prep free- Target
- Margin and line angles: 0.5–1.5 mm
- Why
- A readable finish line is the margin checkpoint; the index shows the room for the crown.
- Watch
- A gap in the chamfer on the lingual is a common miss.
After the lesson: Retake the photos and score again on the 5 checkpoints.
Check 1 of 2 · Margin and line angles
Which cervical margin width is in the acceptable band?
Check 2 of 2 · Putty clearance
On the sectioned putty index, what gap is within?
Sources and 3D credits
Sources: Crown-prep criteria sheet, zirconia molar (#3), 2026–27 season, pp. 1–2 (checked 2026-10-28)
3D model: molar30.glb: teeth #29–#31, jaw bone and gum. BodyParts3D, © 2008 Life Science Integrated Database Center (DBCLS); modified by Osler Press. CC BY-SA 2.1 JP · source
3D viewer code. three.js authors. MIT · source
3D viewer code. three.js authors. MIT · source
Step 6: Finish continuous chamfer and verify clearance with putty index
No prep scored yet · target 0.5–1.5 mm
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TOOLFine diamond and sectioned putty index
CHECKPOINTMargin and line angles: 0.5–1.5 mm
WHYA readable finish line is the margin checkpoint; the index shows the room for the crown.
Do
Finish one continuous chamfer with rounded line angles, then seat the sectioned putty index and read the gap over the prep.
WatchA gap in the chamfer on the lingual is a common miss.
Check 1 of 2 · Margin and line angles
Which cervical margin width is in the acceptable band?
Check 2 of 2 · Putty clearance
On the sectioned putty index, what gap is within?
Sources: Crown-prep criteria sheet, zirconia molar (#3), 2026–27 season, pp. 1–2 (checked 2026-10-28)
3D model: molar30.glb: teeth #29–#31, jaw bone and gum. BodyParts3D, © 2008 Life Science Integrated Database Center (DBCLS); modified by Osler Press. CC BY-SA 2.1 JP · source
3D viewer code. three.js authors. MIT · source
3D viewer code. three.js authors. MIT · source
Outline · 8 parts
✓Criteria card✓Anatomy in 3D3Steps1Depth-orient occlusal grooves2Reduce occlusal table following anatomy3Add functional cusp bevel4Axially reduce walls5Open proximal surfaces with guarded bur6Finish continuous chamfer and verify clearance with putty index4Within vs outside5Check6Guided cut7Cut and score8Recall: day 3 and day 10Practice feedback against the 2026–27 published crown-prep criteria (molar). Not an exam or admissions result; your program and examiners decide.