A Crown is not a filling but is actually mounted on top of an existing tooth to change the shape of the tooth. A crown could be a gold crown. It could be a metal crown. There are some patients who want them in the front.
Then there are porcelain fused to metal crowns, which is really just a metal substructure, which gives the crown more resistance to fracture. Then, on top of that metal goes porcelain. You have the strength of the metal, but then you also have the aesthetics of porcelain. Then you have all porcelain crowns, and all porcelain crowns are the most aesthetic crowns. They’re just as strong as any other crown, and especially nowadays, they’re highly fracture resistant.
You can change the shape or color of a tooth. In a lot of cases, it’s to strengthen the tooth if there are multiple fillings in a tooth or if the tooth had a root canal once upon a time. At that time, you could argue in certain cases that the tooth is more fragile and more prone to fracture.
You place a crown on it to support it and decrease the likelihood of it fracturing. In order to place a crown, it encompasses the entire tooth. It seats over the top of the tooth, and that’s it.