A dental crown is the top of the tooth. Artificial dental crowns are tooth-shaped caps that are permanently cemented over the top of a prepared tooth in order to restore the tooth to normal function and appearance. A dental crown covers the visible tooth from its gum line to the top of the tooth. A crown can be cemented onto the tooth root or a dental implant abutment.
Types of Dental Crowns
There are generally three types of crowns:
- All-ceramic dental crown - a translucent cosmetic restoration that is primarily used for front teeth. This restoration looks like a natural tooth.
- Ceramic veneered to metal dental crown - a cosmetic restoration for visible teeth that require more strength than the all-ceramic restoration.
- Gold dental crown - gold and metal crowns are the strongest and most durable. They are used on molars where chewing forces are greatest.
- Inlay / Onlay - custom partial restorations for the biting and chewing surface of a tooth and used when most of the crown is still intact. Inlays and onlays are conservative restorations requiring less extensive preparation than a full crown.
Types of Porcelain used with Dental Crowns
There are basically two types of porcelain used in dental caps and crowns, these are feldspathic and pressed ceramic porcelains. The feldspathic type is the original method that has been around for 20 years. A Ceramist in a dental lab bakes porcelain onto thin high noble alloy shell and then heats it in an oven. The Ceramist is able to create tints and opaques inside the porcelain of the dental cap or crown to give the natural look we seek.
Pressed ceramic is created from a single ingot. The ingot is melted and pressed in one piece to create the desired shape of the cap or crown. The stains and opaques are applied only to the surface of the porcelain to give a natural look for your new smile.
Resin and Porcelain - Crowns and Onlays
The new reinforced resin or bonded all-porcelain type of cap has the nicest appearance in cosmetic dentistry. This cap can be made from pure ceramic or a new reinforced composite resin. It is almost indistinguishable from natural teeth. The new bonding technology involved provides an exceptional bond your tooth. It is metal-free, and thus satisfies the needs of patients with metal sensitivities. When correcting your back teeth with bonding, the cosmetic dentist will perform a tooth colored onlay. This type of procedure is used to correct only the parts of your tooth that are in need. This procedure is metal-free.
Crowns Made of Gold
Gold crowns are used when appearance is not a priority to you. The gold is extremely workable, making gold crowns a more precise fit than any other type. While there exists a slight possibility of chipping with porcelain crowns, gold crowns provide no such possibility.
Porcelain and Metal Crowns
For a very natural appearance, porcelain fused to metal crowns are the answer for you. However, they have a metal substructure and require an opaque below the porcelain, which can make the translucency of natural teeth difficult to match. Sometimes a darker line will be visible at the edge of the cap, near to your gum when your gum recedes with age.
Dr. Cohen will help you decide which system is the most appropriate to achieve your goals.
Life-expectancy of dental restorations
- All-ceramic crown restorations can last fifteen years or more.
- Porcelain fused to metal crowns can last up to twenty years or more.
- Gold dental crown can last thirty years or more.
The lifespan of a restoration depends on a number of factors including; the location of the tooth and the patient's specific wear of the restoration.