Metal crowns are made of alloys usually gold/base metal alloys. Chromium or nickel are used as base metal alloys.
They have tremendous strength, good quality, last for a very long period, resist chipping and breaking better than other types of crowns.
They are very durable.
They are used for restoration of posterior teeth/molars that are hidden while smiling.
They are suitable in patients who have strong chewing habits and are likely to clench and grind their teeth.
The key drawback is their metallic color making them unaesthetic and not suitable for anterior teeth.
They are best suited for restoring hidden molars.