Contraindications of  Cast restorations are all except:
Grossly carious tooth
Occlusal disharmony
Young patients due to high pulp chambers
Esthetics
Contraindications

Small and shallow cavities.
High plaque / caries indices.
Occlusal disharmony.
Dissimilar metals.
Esthetics.
Young patients due to presence of large pulp chambers.
Old patients due to lengthy and multi step procedures.