What is a Dental Crown?
Dental crowns are custom-made and permanent restorations that help to restore the tooth’s shape, size, strength, and functionality. In addition, crowns can also be used to replace missing teeth in implant cases. They are cemented into place and completely cover the visible portion at and above the gum line. Many different types of materials, such as glass, ceramic, composite, and metal are used to fabricate dental crowns.
A dental crown may be needed in situations to:
What is a Porcelain Crown?
Porcelain crowns are dental crowns made of a biocompatible glass material: dental porcelain. The material is versatile when it comes to appearance and strength with a wide range when it comes to strength–at 200-1100 megapascals (MPa). Depending on the type of porcelain selected, the dental technician can prioritize looks or durability.
How to Fabricate Porcelain Crowns
There are two ways to fabricate all-porcelain crowns: through analog methods or monolithic, computer-aided design and manufactured (CAD/CAM) methods.
When it comes to analog, dental laboratory technicians produce crowns by layering multiple types of porcelains in different shades and translucencies. With this technique, technicians are able to achieve the closest match in color and optical quality.
The other method produces dental crowns through milling. A single, solid, uniform block of porcelain is carved using CAD/CAM software systems to direct and define the shaping. The resulting dental crowns have one standard shade and are therefore not as translucent as man-made porcelain crowns. However, the color matching is as close as possible to the natural teeth.
Types of Porcelain Crowns
IPS e.max is a cosmetic material made from Lithium Disilicate used for porcelain crowns. It can either be pressed or milled. For aesthetic anterior teeth, e.max is the preferred material. It can be used for minimally invasive restorations as thin as 0.2 millimeters (mm). In either technique of fabrication, e.max can be done as a monolithic or micro-layered restoration, the latter being the most cosmetic choice. Recent studies have shown that E.max Press results in a strength of approximately 500 MPA. On the other hand, milled e.max has a strength of 400 MPa. It is beneficial to acid etch e.max before cementation to achieve the ultimate bond strength.
Zirconia is a ceramic material known for its combination of strength and aesthetics that is manufactured in many different variations: Full strength, pre-shaded full strength, anterior esthetic, and pre-shaded multi-layered esthetic, to name a few. Full strength, when processed as a monolithic crown possesses the highest flexural strength of any ceramic restoration at 1100 MPa. Milled through CAD/CAM software, zirconia still remains gentle enough to protect the opposing dentition against excessive wear due to its stringent manufacturing processes. . Esthetic zirconia has an average flexural strength of 650 - 850 MPa. In addition, this material has enhanced light-transmitting abilities, resulting in high translucency and lifelike restorations. Lastly, layered zirconia uses a conventional framework design that is finished with feldspathic-based porcelain. Layering porcelain allows the technician to achieve custom shading, intrinsic characterization, and varying degrees of translucency. However, strength comes at a cost when prioritizing aesthetics with this material. The average flexural strength of Layered Zirconia is 200 MPa.
Porcelain-fused-to-metal crowns are created by covering a strong metal base with a porcelain veneer. The strength of the metal base provides more durability while the porcelain veneer allows for an aesthetic appearance. Clinical studies have shown that PFMs can last at least 10 years over 94 percent of the time. With proper and correct care, they can last up to 20 years. Today, PFM crowns are used more often than all-porcelain because of the added wear and tear resistance. PFM crowns used to cover 83 percent of the total crown fabrication around 15 years ago. However, the percentage has been reduced by about half, mainly contributing to the emergence of stronger materials that do not need a metal base. Despite this, PFM crowns are still among the top three when it comes to fabricating dental crowns. The disadvantage of PFM crowns is that a grey line is possible at the gumline because of the meal base. It’s less aesthetic than an all-porcelain crown. For bruxers or teeth clenchers, this crown is more likely to wear faster and more aggressively against the opposing teeth.
How Can The Dental Lab Help?
At The Dental Lab, we can deliver our all-porcelain crowns in 5-7 business days. We offer many types of porcelains, including IPS e.max CAD, IPS e.max Press, layered zirconia, aesthetic zirconia, and more. In addition, our porcelain-fused-to-metal restorations are typically delivered in 10-12 business days. For a larger scope of our products and services view our Products & Services tab on our website. For questions or concerns, please do not hesitate to contact us.
What Is a Porcelain Crown & How Often Are They Used?
Porcelain Crowns | Types and Uses
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