Crown reduction guidelines

Question 1

Gold/Cast metal

Answer 1

Functional cusp: 1.5 mm
Non-functional: 1.0 mm
Margins: Chamfer

Question 2

SSC

Answer 2

Occlusal: 1 - 1.5 mm
Proximal: 1.0 mm
Buccal/Lingual: no reduction
Margins: Subgingival feather edge

Question 3

Monolithic zirconia anterior/posterior

Answer 3

Ideal reduction of 1.0 mm everywhere
Margins: Rounded shoulder 1 mm

Question 4

Layered zirconia anterior

Answer 4

Incisal: 1.5 - 2 mm
Axial: 1 - 1.5 mm
Margins: 1 mm chamfer

Question 5

Layered zirconia posterior

Answer 5

Occlusal: 1.5 - 2 mm
Axial: 1 - 2 mm
Margins: 1 mm chamfer

Question 6

PFM anterior

Answer 6

Incisal: 1.5 - 2 mm
Facial: 1.2 - 1.5 mm
Axial (porcelain): 1.2 - 1.5 mm
Axial (metal): 1 mm
Lingual: 1 mm

Question 7

PFM posterior

Answer 7

Porcelain occlusal
Functional cusp: 2 mm
Non-functional cusp: 1.5 mm
Buccal: < 1.2 mm
Lingual: < 0.6 mm

Metal occlusal
Functional cusp: 1.5 mm
Non-functional: 1 mm

Margins: Porcelain-metal: 1.5 mm shoulder
Metal: 0.5 mm chamfer

Question 8

Lithium disillicate anterior

Answer 8

Facial: 1.5 - 2 mm
Lingual: 1 -1.5 mm
Incisal: 1.5 - 2 mm