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M1 step 5 of 6 · Guarded tapered diamond
Open proximal surfaces with guarded bur
Break the contacts with #29 and #31 behind a guard, then look at both neighbors directly.
Your last prep
No prep scored yet. Your first score is free with an account.
Score a prep free- Target
- Adjacent tooth: No damage to the adjacent tooth
- Why
- Any nick on a neighbor is scored on the adjacent-tooth checkpoint.
- Watch
- The sheets publish no millimetre band for neighbor damage; untouched is the only safe read.
After the lesson: Retake the photos and score again on the 5 checkpoints.
Check 1 of 1 · Adjacent tooth
A bur nick on #29 needs more than polishing. What is it?
Sources and 3D credits
Sources: Posterior amalgam restoration criteria sheet, 2026.1 season (adjacent-tooth damage), adjacent tooth criterion (checked 2026-11-11)
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 5: Open proximal surfaces with guarded bur
No prep scored yet · target No damage to the adjacent tooth
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TOOLGuarded tapered diamond
CHECKPOINTAdjacent tooth: No damage to the adjacent tooth
WHYAny nick on a neighbor is scored on the adjacent-tooth checkpoint.
Do
Break the contacts with #29 and #31 behind a guard, then look at both neighbors directly.
WatchThe sheets publish no millimetre band for neighbor damage; untouched is the only safe read.
Check 1 of 1 · Adjacent tooth
A bur nick on #29 needs more than polishing. What is it?
Sources: Posterior amalgam restoration criteria sheet, 2026.1 season (adjacent-tooth damage), adjacent tooth criterion (checked 2026-11-11)
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.