There are a number of factors that influence the choice of material for a dental crown – whether it be metal, metal combined with porcelain, or all porcelain. These factors include strength, tooth placement and aesthetics.
Metal crowns, also known as gold crowns, have been used for many years and therefore have a proven record of success. In one retrospective study it was found that 94.1% of all fitted gold crowns and gold fillings were still intact 40 years after their initial placement.
These crowns are often considered a more tooth-friendly option than the others. This is because the amount of tooth structure that needs to be removed before they are placed is less than for metal and porcelain crowns or all-porcelain crowns. In addition, this kind of crown tends not to cause wear on the tooth it sits opposite and it is stronger and more resistant to fracture than the other types of dental crown.
Due to the distinctive gold colouring, however, the main disadvantage of gold crowns is aesthetic. That’s why they are usually only recommended for crowns or bridges of molar (back) teeth, where they would not be visible when the patient is smiling or speaking.
Metal and porcelain crowns
Metal and porcelain crowns – also known as porcelain bonded to metal (PBM) or porcelain fused to metal (PFM) crowns – combine the strength of metal crowns with the aesthetics of porcelain ones. Composed of a metal substructure that is overlaid with porcelain, they have a record of clinical success over a 50-year lifespan, with more than 95% of them surviving more than 10 years.
The main disadvantages of a metal and porcelain crown are that it can cause wear on the opposing tooth and it can develop a grey discoloration near the gum margins.
Relative to their counterparts, porcelain crowns are the most aesthetically pleasing option. Further, recent developments in technology mean they are now extremely strong. While subject to chipping and fractures in certain circumstances, the material used is generally very strong – so much so that it can sometimes wear down the opposite tooth.
The use of porcelain was once limited to veneering of stronger substructures, like metal or stronger ceramics, but they are now a great option for replacing teeth at the front of the mouth, where their excellent aesthetics are a bonus.
Your choice from among the above options will depend on your own priorities and advice from your dentist.