1) DEFINITION

Is an artificial replacement that restores missing tooth structure by surrounding most or all of the remaining structure with a material such as metal, porcelain or porcelain fused to metal.

 

2) ADVANTAGES

• Crowns are much stronger than dental fillings.

• Crowns cover most of the exposed portion of a tooth and can not be decayed.

• Crowns last longer than dental fillings (normally lasts for 5 to 10 years but often last much longer.

 

3) INDICATIONS

• Fractured teeth.

• Badly destroyed teeth (have large old failed filling or severely decayed).

• Cosmetic reasons (to improve the appearance) especially in anterior teeth (discolored, rotated, badly shaped and malformed teeth).

• Strengthen weak teeth thus preventing their extractions.

• Wear of the natural teeth by age exposing the sensitive dentine.

• Sensitive teeth due to cracks.

• Brittle teeth due to root canal treatment.

 

4) TYPES OF CROWNS

• Cast metal crowns.

• Porcelain crowns.

• Porcelain fused to metal crowns.

 

5) CONSTRUCTION STEPS

A- The first visit

• Decay is removed and the tooth is prepared by reducing its size to accept a crown.

• An impression of this section of the mouth is taken.

• A temporary (or transitional) crown of plastic or metal is formed and fitted to the reshaped tooth.

B- Between first and second visits

• The impression is sent to a dental laboratory where a metal cover for the prepared tooth is constructed then the porcelain is baked onto the metal cover so that the porcelain resembles a natural tooth body.

C- The second visit

• The patient returns to the dental office, the temporary crown is removed; the permanent crown is adjusted and cemented to the tooth.