Metal back can be made in a thin section for a close bite. They are expensive. Bonded to Porcelain Crowns. These crownS use a non gold core, often chrome cobalt as the metal core with porcelain bonded on to the core. As the underlying metal is very dark it may be difficult to a good cosmetic result.
Corrosion can occur between the metal of the crown and any underlying metal eg amalgam.
Bonded crown with poor margin, and decay present. Post Crowns Dead teeth are brittle and fracture easily and usually discolour with time. The remaining root is shaped and prepared so that the post can be cemented or bonded into place. Once a post is in place a crown can be constructed to fit over the post to complete the restoration. Blows to teeth with metal posts in place may fracture the remaining root.