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ADEX crown prep criteria for #3, #5 and #9

What the ADEX manikin exam scores on a crown preparation, band by band, as ADEX publishes it for ADEX 2026-2027. Margin width 0.5 to 1.5 mm, reduction 1.0 to 2.0 mm, taper up to 12° per wall.

Checked against the ADEX dental forms on adextesting.org.

Tooth #3 maxillary right first molar

Zirconia crown preparation as the posterior abutment of a 3-unit fixed dental prosthesis (bridge) with #5 (Manual p. 13; criteria sheet: Zirconia Molar)

Margin width 0.5 mm to 1.5 mm

  1. ACCThe cervical margin is > 0.5 mm but ≤ 1.5 mm in width.
  2. SUBThe cervical margin is > 1.5 mm but ≤ 2.0 mm in width.
  3. DEFA. The cervical margin is > 2.0 mm in width. B. The cervical margin is < 0.5 mm in width.

ADEX sheet, page 1

Axial reduction (axial tissue removal) 1.0 mm to 2.0 mm

  1. ACCThe axial tissue removal is ≥ 1.0 mm but ≤ 2.0 mm.
  2. SUBThe axial tissue removal is > 2.0 mm but ≤ 2.5 mm.
  3. DEFA. The axial tissue removal is > 2.5 mm. B. The axial tissue removal is < 1.0 mm.

ADEX sheet, page 1

Taper up to 12° per wall

  1. ACCTaper is present, from nearly parallel to ≤ 12°.
  2. SUBThere is excessive taper that is > 12° and ≤ 16°.
  3. DEFThe taper is grossly over-reduced > 16° per wall.

ADEX sheet, page 2

Occlusal reduction 1.0 mm to 2.0 mm

  1. ACCThe occlusal reduction is ≥ 1.0 mm but ≤ 2.0 mm.
  2. SUBThe occlusal reduction is > 2.0 mm but ≤ 2.5 mm.
  3. DEFA. The occlusal reduction is > 2.5 mm. B. The occlusal reduction is < 1.0 mm.

ADEX sheet, page 2

Tooth #5 maxillary right second premolar

Zirconia crown preparation as the anterior abutment of the same 3-unit bridge (Manual p. 13; criteria sheet: Zirconia Premolar)

Margin width 0.5 mm to 1.5 mm

  1. ACCThe cervical margin is > 0.5 mm but ≤ 1.5 mm in width.
  2. SUBThe cervical margin is > 1.5 mm but ≤ 2.0 mm in width.
  3. DEFA. The cervical margin is > 2.0 mm in width. B. The cervical margin is < 0.5 mm in width.

ADEX sheet, page 1

Axial reduction (axial tissue removal) 1.0 mm to 2.0 mm

  1. ACCThe axial tissue removal is ≥ 1.0 mm but ≤ 2.0 mm.
  2. SUBThe axial tissue removal is > 2.0 mm but ≤ 2.5 mm.
  3. DEFA. The axial tissue removal is > 2.5 mm. B. The axial tissue removal is < 1.0 mm.

ADEX sheet, page 1

Taper up to 12° per wall

  1. ACCTaper is present, from nearly parallel to ≤ 12° per wall.
  2. SUBThere is excessive taper that is > 12° and ≤ 16° per wall.
  3. DEFThe taper is grossly over-reduced > 16° per wall.

ADEX sheet, page 2

Occlusal reduction 1.0 mm to 2.0 mm

  1. ACCThe occlusal reduction is ≥ 1.0 mm but ≤ 2.0 mm.
  2. SUBThe occlusal reduction is > 2.0 mm but ≤ 2.5 mm.
  3. DEFA. The occlusal reduction is > 2.5 mm. B. The occlusal reduction is < 1.0 mm.

ADEX sheet, page 2

Tooth #9 maxillary left central incisor

All-ceramic crown preparation on a central incisor (Manual p. 13; criteria sheet: Ceramic Incisor)

Margin width 0.5 mm to 1.5 mm

  1. ACCThe cervical margin is ≥ 0.5 mm but ≤ 1.5 mm in width.
  2. SUBThe cervical margin is > 1.5 mm but ≤ 2.0 mm in width.
  3. DEFA. The cervical margin is > 2.0 mm in width. B. The cervical margin is < 0.5 mm in width.

ADEX sheet, page 1

Axial/lingual tissue reduction 1.0 mm to 2.0 mm

  1. ACCThe axial/lingual tissue reduction is ≥ 1.0 mm but ≤ 2.0 mm.
  2. SUBThe axial/lingual tissue reduction is > 2.0 mm but ≤ 2.5 mm.
  3. DEFA. The axial/lingual tissue reduction is > 2.5 mm. B. The axial/lingual tissue reduction is < 1.0 mm.

ADEX sheet, page 1

Taper up to 12° per wall

  1. ACCTaper is present, from nearly parallel to ≤ 12° per wall.
  2. SUBThere is excessive taper that is > 12° but ≤ 16° per wall.
  3. DEFThe taper is grossly over-reduced > 16° per wall.

ADEX sheet, page 2

Incisal reduction 1.0 mm to 3.0 mm

  1. ACCThe incisal reduction is ≥ 1.0 mm but ≤ 3.0 mm.
  2. SUBThe incisal reduction is > 3.0 mm but ≤ 3.5 mm.
  3. DEFA. The incisal reduction is > 3.5 mm. B. The incisal reduction is < 1.0 mm.

ADEX sheet, page 2

How the bands work

ACC is clinically acceptable, SUB marginally substandard, DEF critically deficient. Margin width and reduction are deficient on both sides: too little and too much.

Taper is scored per wall, not as total convergence.

Three confirmed SUB ratings for over-preparation on one procedure count as critically deficient (ADEX Clinical Candidate Manual).

Sources

Osler Press is not affiliated with ADEX. Always read the current sheet before your exam.

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