Crowns

If your tooth is damaged but not lost, a crown (also called a cap) can be used to cover the damaged part of your tooth. A crown protects your tooth from further damage. You may need a crown if:

You Have a Root Canal; 
You Have a Large Filling in a Tooth; 
You Have a Broken Tooth; Or 
Your Tooth Is Badly Stained, Not the Right Shape or Out of Line. 
Crowns Can Be Made of Different Kinds of Metals, Porcelain or Porcelain Fused to Metal. They Are 
Strong and Last for About 10 Years, if You Take Good Care of Them. Brush and Floss Your Crown, Just Like
You clean your natural teeth.

But crowns and replacement teeth may not be as strong as your natural teeth, so:

Do Not Bite Down on Hard Objects; 
Do Not Use Your Teeth to Open or Cut Things; And 
Do Not Do These Things with Your Natural Teeth Either.
 
 
Here's How a Crown Is Made:
 
 
Step 1
Your dentist may make a mold (or an impression) of your tooth to fit a temporary crown. It protects your tooth until the final, permanent crown is ready. Temporary crowns may not have the same shape and colour as permanent ones.
 
Step 2
Your dentist gives you freezing (called a local anesthetic). He or she then files down your tooth to make room for the crown.
 
Step 3
Another mold (or impression) is taken of the filed-down tooth and nearby teeth. Then the temporary crown is placed over your tooth and you are sent on your way.
 
Step 4
This mold is sent to a dental lab, where your permanent crown is custom-made. The mold of your tooth is used to make a model. A filling (or restoration) that is the same size and shape as your tooth is built based on the model.
 
Step 5
On your next visit, your dentist takes off the temporary crown and puts on the permanent one. Then he or she checks to make sure the crown is the right fit, shape and colour. If it is, your dentist cements the crown into place. Your tooth will look and work very much like a natural tooth.