How Does a Dentist Prepare Teeth for a Crown?

The process is fairly simple, in that the dentist would make you comfortable (numb etc) and remove enough tooth structure to reinforce the tooth. An impression of the prepared tooth is made and a temporary crown fabricated over the prepped tooth. The temporary and final crown fit similar to how two inverted styrofoam cups fit together. The perfect fit creates some retention (in this case suction). Cement is added to the crown for permanent retention.

Reduction of 0.5 or 1.0 mm on the sides of the tooth and up to 2.0 mm on the top or tip of the tooth is all that is needed.  4.0 mm is WAY more than needed, and MOST dentists will not reduce a tooth by this much.

A well done crown should fit comfortably and eventually feel like nothing was ever done.

Crown preparation is a routine procedure which should be 100% pain free with properly administered local anesthesia. The dentist simply reduces the tooth in a  circumferential manner  to allow ample room for the crown to be placed. Proper reduction of the tooth will allow for the Crown to be structurally durable while at the same provide a natural feeling to the patient in terms of size and fit. If the Crown is to be made at a Dental Lab the Dentist will fabricate an Acrylic Temporary Crown to keep the patient comfortable until the Permanent Crown is delivered to the patient. This process generally takes about two weeks to complete.

To fit a cap over a tooth you have to allow room for it .

your dentist will reduce the tooth in all directions and check your bite to see that there is enough clearance for the dental technitian to stack the porcelain and or metal/porcelain 

The guidelines are a space of at least 2 to 4 mm around and on top of the tooth ;to carve this space your dentist will make you fully numb and will let you go home with an acrylic temporary crown to protect the tooth