Dental Crowns

Lithium disilicate jacket crown. Photo credit: Dr. Jesus Orlando Lecitona

Synonyms : Jacket, Jacket Crown, Crown Restoration, Cap

A dental crown is a dental restoration that covers a tooth to restore it to its normal shape, size and function. Its purpose is to strengthen or improve the appearance of a tooth.

A dental crown can
– restore a tooth when there isn’t enough tooth remaining to provide support for a large filling
– attach a bridge to replace missing teeth
– protect weak tooth from fracturing
– restore a fractured tooth
– cover a badly shaped or discolored teeth
– cover a dental implant

What is it made from?

The look and function of a crown are considered when choosing the material ideal for your case.

Crowns are made from several types of materials: metal alloys, porcelain, composite resin, or combinations of these materials.

Types of Crowns

Stainless steel crowns can be prefabricated and can also be custom-made. They are used on permanent teeth primarily as a temporary measure. They are used in primary dentition to protect the teeth of a child at high risk for tooth decay, especially when a child has difficulty keeping up with his/her oral hygiene.

Metal crowns can be made of gold alloy, base-metal alloy (ie nickel or chromium) and other alloys (ie. palladium). Compared with other crown types, less tooth tissue needs to be removed with metal crowns, and tooth wear to opposing teeth is minimal. Metal crowns can withstand great occlusal and masticatory forces well and lasts long in terms of wear down.

Porcelain crowns have many types:
Metal ceramic / porcelain fused to metal
High-strength cores
Pressed-glass ceramics
Milled porcelain
Capillary technique

Metal ceramic, also called as porcelain fused to metal, crowns are the conventional and most commonly used dental crowns. It utilizes the bond between porcelain and metal that is achieved at high temperatures. Enough space is needed from tooth prep for the opaque porcelain, dentin and enamel porcelain to create the appearance.

High strength core crown consists of 2 layers. The dental crown’s strength is derived from the inner core made from Inceram, and overlaid with conventional porcelains to improve the esthetics. Inceram is a glass and alumina material.

Fine alumina powder is applied to an absorbent refractory die and any residual pores are filled with molten glass to produce a dense, crystalline core structure. The core has high strength and elastic modulud. The high content of alumina makes it resistant to acids making adhesive bonding difficult.

Pressed-glass ceramic crowns comprise 2 layers, an inner material made from Empress or E.max and an outer layer made from conventional (feldspathic) porcelains. The outer layer is thinner than in hign strength core crowns. This is to improve the surface finish and characteristics. The core is made using the lost wax technique. Wax is applied to a phosphate-bonded investment, after burnt-out, leucite reinforced glass ceramic is pressed under pressure into the space.

In milled-porcelain core crowns, computer controlled technology is used to mill the coping. The ingot is made from an aluminum oxide. The ingot can also The outer surface is made from conventional porcelain. The fit is excellent. Conventional porcelain is overlaid onto the core which is responsible for the improved translucency.

In milled-porcelain high strength core crowns, computer controlled technology is used to mill the coping. The coping is made from zirconium oxide. The outer surface is made from conventional porcelain.

Capillary technique (Captek) dental crown‘s basic structure is smilar to metal ceramic crowns except that the core is made from a precious metal. Captek have improved marginal fit and biocompatibility. The apperance is warmer compared to conventional PFM crowns because the yellow color from the gold core reflects the light. Captek requires less tooth reduction.

Monolithic CAD-CAM milled dental crowns. In CAD CAM crowns, blocks of porcelain is cut by computer aided design/computer aided manufacturing system to produce crowns.

All-resin dental crowns are less expensive than other crown types. They can be used for temporary purposes.

Acrylic dental crowns the least espensive among the dental crowns. They are primarily fabricated as temporary crowns.

Plastic jacket crown. Photo credit: Dr. Jesus Orlando Lecitona

The dental crown made looks natural and feels comfortable. It will restore the beauty and function of your smile.

Dental Crown Care

To prevent damage or fracture to a dental crown, avoid chewing hard foods. Avoid biting on hard objects. Brush every other meal. Floss once a day. Visit your dentist for regular mouth examination and professional teeth cleaning.

Why do I need a crown? American Dental Association
Types of Porcelain Dental Crowns

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