Manufacturing requirements of cast metal crown impression

1, buccolingual surface-eliminate undercut, reduce the maximum circumference of axial surface to the edge of full crown, and prepare metal crown with required thickness, about 0.5 ~ 1.0 mm, and the occlusal convergence angle is 2 ~ 5.

2. Adjacent surface-eliminate undercut, separate from adjacent teeth, form a coordinated penetration path, and prepare the gap between adjacent surfaces required by metal crown, about 0.5 ~ 1.0 mm, and the occlusal polymerization angle is 2 ~ 5.

3. Neck shoulder-circular concave shoulder or oblique shoulder, with a width of 0.5 ~ 0.8 mm, continuous and consistent edges, smooth without rough surface and sharp edges.