Metal crowns generally make use of gold alloys or base metal alloys like that of chromium or nickel.
If compared to the other crown types with metal, minimal amount of tooth structure has to be removed and wearing out of adjacent teeth is also minimal.
Since these crowns are made of metals, they can withstand chewing and biting forces well and last for over a very long period. They hardly break or chip off.
The key drawback of metal crowns is their metallic color. They are best suited for restoring hidden molars.
Advantages of metal crowns
- The most significant advantage of metal crowns is their tremendous strength.
- Crowns made completely of gold are of very good quality.
- Metal crowns cause minimal wearing of the surrounding teeth as compared to others.
- Metal crowns require very little amount of filling for the tooth.
- Metal crowns last for a very long period and resist chipping and breaking better than other types of crown.
- They are very durable and are used for the restoration of hidden teeth.
- These are best suitable for patients who have strong chewing habits and are likely to clench and grind their teeth often. Thus, metal crowns are suited for the back teeth.
- The only main disadvantage of metal crowns is their metallic appearance.
Metal crowns are sometimes prepared with porcelain fused to them and are referred to as porcelain fused to metal crowns (PFM). They have a strong metal core in the inside and then a layer of porcelain is cemented on it. The final look is that of a natural tooth.
Advantages of PFM crowns:
- In case of purely metal crowns, the metallic shine is a drawback but here the shade exactly matches the shade of the patients tooth.
- These crowns can be easily used on tooth which is visible unlike the all-metal crowns.
- The quality of these crowns is very durable and superior as they have a metal in their core shell.
- They have enough strength, are highly durable, and can easily bear strong chewing forces.
- These porcelain crowns can cause wear and tear of the surrounding teeth causing pain and infections.
- There are more crowns that are vulnerable to breaking and chipping as compared to all metals.
- Since the porcelain covering is translucent, it sometimes makes the underlying metal visible which can be embarrassing for the patient.
- In case the gums recede, problems at the gum line of the crown may result.
Metal crowns are fixed in the same way as other crowns. It requires two successive visits to the dentist to get them permanently fixed.
On the first visit, a number of X-rays of the concerned tooth are done and then it is numbed.
All decay is cleared and then an impression of the teeth is taken.
While the permanent crown is prepared, a temporary crown is placed on the tooth to protect it.
After the permanent crown has arrived, it is cemented to the tooth permanently.