Dental crowns can provide stability and strength to a tooth that is in need of some help. Many people use a crown instead of having dental bonding done, because the dental crown works well at holding the tooth together. There are 3 types of crowns that you can get, all of which have their own benefits.
Full Dental Crown
Much like the name implies, a full dental crown will be placed over the entire tooth. This is ideal for a tooth that has weakened enamel, a large cavity, a crack, or has a portion of the tooth that broke off.
A full dental crown is constructed using porcelain. However, there are variations of full dental crowns that use metal along the back to make the material stronger. The exterior of the crown still has that natural look, so nobody will be able to tell the difference when you smile. There's a small piece of metal that will be visible along the bottom, but it will be hidden under your gum line.
Three-Quarter Dental Crowns
The three-quarter dental crown does not cover the entire tooth, but a portion of it. It's common to use a three-quarter crown when a tooth has a side that is still healthy, and strength just needs to be added to a single side. The crown is installed by bonding it to your existing tooth, which leaves the healthy part of the tooth exposed.
Many people prefer the three-quarter dental crown because it causes your bite to still feel natural. The crown also uses less porcelain material, so it will have a lower cost associated with it. The three-quarter crown can be noticeable to others, and is used on rear teeth where people typically don't see it.
Onlay Dental Crowns
An onlay dental crown is used in situations where a full dental crown is not necessary. This includes issues where a large filling needs to be installed, or when the damage is in the middle of the tooth rather than the sides. The crown only covers the top portion of the tooth's existing crown, rather than extending to the sides.
Onlays don't have metal backing under them, since others would easily be able to spot the edges of the crown if it did. Onlays are best used on teeth that don't require force when chewing, which make front teeth a good candidate for the crown.
For more info on dental crowns, speak to your dentist.