Table 1

Evaluation rubric for pre-formed metal crown preparation

Evaluation CriteriaCompetentNot Competent
Mesial interproximal slice
  • 15–20° taper

  • Contact point cleared

  • Chamfer margin

  • Taper < or > 15–20°

  • Contact point not cleared

  • Step margin

Distal interproximal slice
  • 15–20° taper

  • Contact point cleared

  • Chamfer margin

  • Taper < or > 15–20°

  • Contact point not cleared

  • Step margin

Occlusal preparation
  • Reduced by 1.5 mm

  • Follows occlusal contour

  • Reduced by < or > 1.5 mm

  • Flattened occlusal surface

Finish
  • Smooth preparation

  • Sharp angles

  • Rough finish