A dental crown or “cap” preserves a damaged tooth by encasing it with a custom-designed material. Your dentist may employ the use of a crown to protect and restore a tooth that is decayed or cracked. A dental crown may also replace a pre-existing crown.
Dental bridges, also known as fixed partial dentures, are an extension of the dental crown treatment and fill in the gap caused by a missing tooth. Nowadays, dentists may recommend the placement of dental implants rather than fixed partial dentures. An implant is surgically attached in the jaw space and a crown is then placed on the implant above the gumline.
A full coverage crown may be constructed using one of three main restorative materials: all-ceramic/ all-porcelain, porcelain-fused-to-metal, and gold. The material chosen is determined by the specific clinical issue, durability of the material, strength requirements, the space available for the restoration, and esthetic needs.
All-ceramic crowns contain either zirconia or aluminous materials. Because they do not contain metal, all-ceramic crowns may be thinner and of advantage when space is limited. They have a further benefit of being esthetically pleasing by way of allowing for translucency through the porcelain. With those teeth that are heavily utilized, all-ceramic crowns may be a less favorable option, although ceramic materials continue to develop increasing strength and durability.
Porcelain-fused-to-metal crowns offer a strong, esthetic, and long lasting treatment option. With these crowns, it is important that the dentist prepares sufficient space in the underlying tooth structure to fit the crown according to its thickness. The laboratory technologist making the crown will need to have high artistic skill to produce an esthetically appealing crown.
A point to note with porcelain-fused-to-metal crowns is that they may tend to reveal the underlying metal or gold edge at the gum line as gums pull away from the teeth over time. To counteract this problem, some people select a porcelain-fused-to-metal crown with an all porcelain collar, or replace the crown later on in order to keep the tooth looking natural and pleasing.
Crowns made with gold are less popular than the esthetic ceramic crowns. However, because they offer a stronger support to the remaining healthy tooth structure, gold crowns may be advised for people with strong bites or those who tend to grind or clench their teeth. Gold crowns are suitable for the back teeth, such as the molars, which are less visible than the front teeth. Further advantages are that they last longer and require less preparation than porcelain and porcelain-fused-to-metal crowns. They are also less likely to wear down the surrounding teeth when chewing.
Dental Crown Procedure
Before fitting a crown, your dentist will prepare the tooth and have an impression of your teeth molded. Your dentist will construct a fitted, temporary crown for the purpose of protecting the tooth. The molded impression will be sent to a dental laboratory where the crown will be made. At a later visit, the final crown is cemented or adhesively bonded in place of the temporary crown.
Some dentists have the advantage of using a computer-aided design/manufacturing technology (CAD/CAM) in their office to construct the dental crown on site. In this case, a temporary crown will not be necessary and the complete procedure can be done within a single session.