Preformed malleable dental crowns with a side-generic external shape with a plane of symmetry in the facial-lingual direction and/or a plane of symmetry in the mesial-distal direction. The preformed dental crowns also include a hardenable composition that has sufficient malleability such that the side-generic external shape can be formed into, e.g., a left-side specific or right-side specific adjusted external shape. Methods of the invention may include fitting the dental crowns by adjusting or forming them to provide side-specific features, followed by hardening of the hardenable composition.