When teeth become cracked, damaged or broken down, dental crowns (also known as dental caps) are one option for restoring them. Placed on top of an existing tooth, a crown is an artificial top which covers the entire outer surface of the tooth and replaces damaged material.
There are many reasons to consider a crown as a solution; functionality, for example. A large section of your tooth may have fractured, and be beyond the help of traditional bonding techniques. The tooth may be too badly decayed to support a filling or an inlay. Furthermore, over time your teeth may have physically worn down to the point where they need to be restored to their original size.
Another possible reason is that you have just had a root canal operation or a titanium implant fitted, and may need a crown placed to strengthen the results.
You may, of course, just want a crown to improve the aesthetics of your smile. While this is possible, you should bear in mind that a significant amount of the original tooth may have to be removed and therefore consideration should be given to whether a less intrusive treatment such as veneers could get the results for which you are looking.