A dental crown is a cap placed on a tooth, so that it completely encapsulates it above the gum. Its external shape is shaped exactly like the tooth in its original condition. Normally, the crown is permanently cemented into place, but can be removed by a dentist if necessary. Temporary crowns, made of a cheaper material, may be placed pending the construction of a permanent crown.
Why Crown a Tooth?
Some of the situations demanding a dental crown are:
- To save a weak or damaged tooth from breaking, or to protect a cracked tooth.
- To protect a tooth that becomes brittle after root canal treatment.
- After restoring a broken, badly worn down tooth.
- A tooth with a large filling will naturally be weak, because not much of the original tooth may be left. A crown will help protect this tooth.
- A crown may be used to hold a dental bridge in place.
- To cover badly shaped or badly discolored teeth.
- A crown may be used to cover a dental implant.
- Finally a crown may be placed simply for cosmetic reasons.
Crowns for Children’s Teeth
Crowns are normally applied to teeth of adults, but under certain situations crowns may be applied to baby teeth. As an example, a tooth so badly damaged that it cannot support a filling would often be crowned. Crowns may be applied to protect the teeth of children with a very high risk of tooth decay. In such cases, steel crowns may be recommended.
Permanent crowns can be divided into different classes, according to the material used. It could be metal (stainless steel, or alloy containing gold or other metals), porcelain-fused-to-metal, resin, or ceramic.
Stainless steel crowns are used on baby teeth, or as prefabricated temporary crowns on adults while a permanent crown is being prepared. Steel crowns are more cost effective for baby teeth. Metal alloys are more appropriate for permanent crowns. Metal crowns have the advantage of strength against wear, and against the pressure of chewing forces. Also, little volume needs to be removed from the host tooth to accommodate metal crowns, because they can be made thin and yet have the desired physical strength. The disadvantage is the color of the metal. For this reason, metal crowns are a good choice for molars which are mostly out of sight.
Dental crowns made from porcelain fused to metal have the advantage that they can be color matched to the nearby teeth. They are the best aesthetic choice, after all-porcelain crowns. However, they will because more wear on the opposite teeth, due to friction, than metal crowns. The porcelain may chip off, and sometimes, the metal underlay may become visible near the gum line, if the gum recedes. These can be a good choice for front or rear teeth.
All-resin dental crowns are the least expensive. However, they wear down over time and are more likely to fracture.
All-ceramic or all-porcelain dental are best for a color match. Also they will suit people with metal allergies. But they lack in strength and wear out more compared to all other types. They are a good choice for front teeth.
Zirconia or Milled Crown
Zirconia ceramic crowns are widely being used nowadays, due to their excellent biocompatibility and strength. These crowns can either be fabricated in the dental lab, or can be fabricated at the dental chairside using the “computer aided design-computer aided manufacturing” (CAD-CAM). Some dentists may have the equipment produce a permanent crown in the office itself. The equipment is a small milling machine which operates under software control. This will save the patient a second visit as no prior impression is needed.
Don’t be Afraid to Ask Questions
Usually if you need a crown, we’ll be the first to inform you. However, all the above information is a lot to take in. Please don’t hesitate to ask questions or schedule an exam if you think you may need work done, including crowning a tooth. The dental assistants and dentists in our Arlington office will be happy to help you make educated decisions that best suit whatever is happening in your mouth.