Metal crowns are entirely cast in metal alloys alloys that have a high content of gold or platinum, or base-metal alloys (for example, cobalt- chromium and nickel-chromium alloys).

Advantages

• Most significant advantage of metal crowns is their tremendous strength, they are extremely unlikely to break or fail and can be good for patients who have badly damaged posterior teeth as they withstand biting and chewing forces well and probably last the longest in terms of wear down.
• Metal alloy (gold crowns in particular) have extremely good biocompatibility with gingival tissue and are unlikely to promote any allergic reactions.
• Metal crowns last for a very long period and require lesser replacements as metal crowns rarely chip or break.
• Metal crowns cause minimal wearing of the surrounding teeth as compared to other materials.
• Metal crowns require a very little amount of trimming of the tooth, so are preffered in cases with less occlusal clearance
• They are very durable and are used for the restoration of teeth that are not visible
• These are best suitable for patients who have strong chewing habits and are likely to clench and grind their teeth often.

Disadvantages:

• The metallic color is unaesthetic , these crowns are a good choice for out-of-sight molars.
• High price of gold is another reason for patients opting for more economical and more aesthetic options .
• Porcelain-fused-to-metal dental crowns (PFM) crowns are a combination of porcelain and metal.

The porcelain overlay is color-matched to your natural teeth (unlike the metallic crowns). However, more wearing to the opposing teeth occurs with this crown type compared with metal or resin crowns. The crown's porcelain portion can also chip or break off. Next to all-ceramic crowns, porcelain-fused-to-metal crowns look most like normal teeth. However, sometimes the metal underlying the crown's porcelain can show through as a dark line, especially at the gum line and even more so if your gums recede. These crowns can be good choice for front or back teeth as well as long bridges where the metal is needed for strength.