Amounts of Tooth Preparation

Metal crown 修磨量：

1. Occlusal reduction
• functional cusp-- 1~1.5 mm
• nonfunctional cusp-- 0.5~1 mm
2. Axial reduction-- 0.5~1 mm
3. Supragingival margin-- 0.5 mm

PFM (Porcelain Fused to Metal) crown 修磨量：

1. Occlusal reduction
• functional cusp-- 1.5~2 mm
• nonfunctional cusp-- 1~1.5 mm
2. Axial reduction
• buccal side-- 1.2~1.5 mm
• lingual (palatal) side-- 0.5 mm 
• proximal area-- 0.5 to 1.2 mm (lingual to buccal)
3. Subgingival margin-- 0.5~1 mm

All-Ceramic crown 修磨量：

1. Occlusal reduction
• functional cusp-- 2.0 mm
• nonfunctional cusp-- 1.5 mm
2. Incisal reduction-- 1.5~2 mm
3. Axial reduction-- 1.0~1.5 mm
4. Subgingival margin--0.5~1 mm (use rounded shoulder or heavy chamfer bur)