Crowns or onlays (partial crowns) are needed when there is insufficient tooth strength remaining to hold a filling. In other words, they are used to restore a fractured tooth or to protect weak teeth from breaking. They may also be used to attach a bridge, to cover badly shaped or discolored teeth, or to cover a dental implant.
Both the "look" and function of your crown is considered when choosing the material most suitable for you. Your dentist will consider the tooth location, the position of the gum tissue, the amount of tooth that shows when you smile, the color or shade of the tooth, and the fA crown covers, or caps, a tooth to restore it to it's normal shape and size. In effect, the crown becomes your tooth's new outer surface. It's purpose is to strengthen or improve the appearance of a tooth.unction of the tooth.
Crowns can be made of porcelain, gold, or both. Porcelain is a type of glass that mimics the appearance of natural teeth quite well so it is always used in esthetic. Unlike fillings which are applied directly into your mouth, crowns are custom created in a lab from your unique teeth impression.
Several steps are involved in placing a crown so two visits are necessary. At the first visit, the dentist will prepare the tooth by removing any decay and possibly filling material then removing the outer portion of the tooth to accomodate the thickness of the crown. An impression is taken to provide an exact model of the prepared tooth and the teeth around it. A temporary crown made of a plastic resin is fabricated and placed on your tooth while your custom crown is being made. The impression that was taken is sent to a dental lab where a technician, following the written instruction of the dentist, will sculpt or create your crown ,taking into account your bite and jaw movements as well as the shape of your other teeth and the desired appearance. For front teeth, the dentist will usually take photographs to help the technician visualize these teeth.
When the crown is ready (usually 2 weeks), the dentist fits the crown to your tooth and makes any necessary adjustments. Your bite will be checked and you can see how your crown will look. When you and your dentist are satisfied, the crown will be cemented or glued into place.