If you have severe tooth decay or have cracked teeth, dental crowns can restore strength, shape and appearance. Crowns can also reduce sensitivity and help you eat normally.
The best option depends on your preferences, needs and situation. Porcelain crowns look natural a 韓国ホワイトニング nd withstand biting and chewing forces. However, they may wear down faster than other types of crowns.
Porcelain Crowns
Crowns are used to protect, strengthen and preserve a natural tooth that has been severely compromised due to a crack, chip, severe discoloration, or other dental work such as root canal therapy. They fit over the core of a tooth like a hat fits on your head, preventing the core from breaking off and halting a potential fracture of the root.
Porcelain crowns are made from a translucent porcelain that can match the color of the natural tooth it is covering, and they can be bonded directly to the natural tooth. They can also be made as part of a same day in-office procedure using CEREC (computerized milling machine), which allows for a stronger, more durable, and more aesthetic crown.
There are many different types of porcelain crowns but the most common are called feldspathic 韓国ホワイトニング crowns. This is the traditional crown that has been around for years and works well. However, newer and better crowns are available – such as lithium disilicate (Emax). These crowns are incredibly strong but also very luminous. They are a good choice for front teeth and do not require as much of the natural tooth structure to be shaved away than some other crowns.
Another type of porcelain crown that is popular is a one layer system, known as a Procera crown. These are a little thicker than other crowns, and they have an aluminium oxide core that is custom milled on a CAD/CAM machine before a highly customized superficial layer of feldspathic porcelain is layered over the top. They are a very good option for back teeth as they are very durable and do not require as much of the natural teeth to be shaved away.
There are also PFM or porcelain fused to metal crowns, which have a metal base that attaches to the natural tooth and then a porcelain cap that covers the metal. These are a good choice for molars because they provide extra strength that can withstand chewing and grinding, but they can show the metal in the gum line when biting down and do not look as good as an all porcelain crown. Another newer type of crown that is metal free is zirconia crowns which follow the same manufacturing process as a porcelain crown, but do not have any metal in them at all. These are a good option for nighttime bruxers and can be made very strong. They are still a bit softer than an E Max layered crown though.
Metal Crowns
If a tooth has significant decay, cracking or previous root canal treatment, a crown is often the best option. The strength and durability of a crown can make the tooth more resistant to further decay, and also provide support for a filling or bridge if needed. In addition, a crown can protect a vulnerable tooth from further damage if it is clenched or grinded (bruxism).
Unlike natural teeth, dental crowns are not exposed to bacterial acids that can dissolve the tooth structure over time. Therefore, it is important that a patient keeps their regular appointments to prevent further decay, and to ensure the crown remains in place.
The most common type of crown is made from porcelain. The porcelain is colour matched to the surrounding teeth for best cosmetic results. However, the lack of transparency in porcelain means that it may not be ideal for front teeth. Porcelain-fused-to-metal crowns are a good compromise, as they can be made from a stronger metal and the porcelain can be overlaid onto the tooth for a more natural appearance. These are made at VC Dental on our CEREC machine in-house.
Another type of dental crown is made from stainless steel. This is a more cost effective option as the crown does not require any laboratory work. It is most commonly used for molars (the chewing teeth at the back of the mouth). Stainless steel crowns can have a dark metallic look to them, but they are a strong and durable restoration.
Alloys of gold, silver, chromium and nickel can be used to create a metal dental crown. The best metal crowns are high noble alloys, which contain at least 60 percent of precious metals such as gold and platinum. This gives the crown the highest level of strength, wear resistance and biocompatibility. Non-noble alloys generally have less of a noble metal content, and are considered lower quality crowns. Non-noble alloys are often made from cobalt, nickel and chromium, and are often used for back molars as they are more resistant to corrosion and tarnish.
Before the crown is fabricated, the dentist will anaesthetise and prepare the tooth. This can involve removing any decay or damaged areas of the tooth, and reshaping it to accept the crown. A temporary crown will be placed to protect the tooth until the permanent one is ready. Once the crown is ready, the dentist will bond it into place and the procedure is complete.