Within vs outside

Each checkpoint, within the band and outside it. Turn on Compare to see a prep within the bands next to one outside them (over-tapered walls, a nicked neighbour).

Loading 3D view…

The model's two preps in section, buccal to lingual. Each angle is one wall against the path of insertion (dashed). The band is ≤ 12° per wall.

Checkpoint	Within	Outside	Replay
Occlusal reduction	A reading inside the acceptable occlusal band.	A reading over the band or under it: marginally substandard or critically deficient.	Step 6
Axial taper	Each wall read on its own, inside the band per wall.	One wall over the band per wall, even if the others are inside.	Step 2
Margin and line angles	A finish line width inside the acceptable band, all the way round.	A width out of the band anywhere on the finish line.	Step 4
Adjacent tooth	The right neighbors, named by number, untouched.	A nick on a neighbor that needs more than polishing.	Step 1
Putty clearance	The buccal photo shows a gap of at least the occlusal minimum under the index.	The index touching the prep, or no index in the buccal photo.	Step 5

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

Back Next: Check

English한국어

✕M0 · Orientation9/13

Within vs outside

Each checkpoint, within the band and outside it. Turn on Compare to see a prep within the bands next to one outside them (over-tapered walls, a nicked neighbour).

Loading 3D view…

The model's two preps in section, buccal to lingual. Each angle is one wall against the path of insertion (dashed). The band is ≤ 12° per wall.

Checkpoint	Within	Outside	Replay
Occlusal reduction	A reading inside the acceptable occlusal band.	A reading over the band or under it: marginally substandard or critically deficient.	Step 6
Axial taper	Each wall read on its own, inside the band per wall.	One wall over the band per wall, even if the others are inside.	Step 2
Margin and line angles	A finish line width inside the acceptable band, all the way round.	A width out of the band anywhere on the finish line.	Step 4
Adjacent tooth	The right neighbors, named by number, untouched.	A nick on a neighbor that needs more than polishing.	Step 1
Putty clearance	The buccal photo shows a gap of at least the occlusal minimum under the index.	The index touching the prep, or no index in the buccal photo.	Step 5

Outline · 8 parts

✓Criteria card ✓Anatomy in 3D ✓Steps 1Find tooth #30 and tooth #3 2Name the five surfaces of #30 3Peel enamel, dentin and pulp 4Read the five checkpoints on a finished prep 5Photograph the prep on the grid card 6Read your score band by band 4Within vs outside 5Check 6Guided cut 7Cut and score 8Recall: day 3 and day 10

Practice feedback against the 2026–27 published crown-prep criteria (molar). Not an exam or admissions result; your program and examiners decide.

Back Next: Check