What are Dental Crowns or in other words Dental Caps?

Crowns are a type of dental restoration which, when cemented into place, fully cup over the portion of a tooth that lies at and above the gum line. In comparison, fillings are dental restorations that fill in or cover over just a portion of a tooth. Since dental crowns cover the entire visible aspect of a tooth, a dental crown in effect becomes the tooth's new outer surface.
Crowns can be made out of porcelain . Other terms that are used to refer to dental crowns are "dental caps" and "tooth caps."

Why do teeth need Dental Crowns?

The dentist might recommend of placing a dental crown for a variety of reasons but, in general, most of these reasons will usually fall within one of the following basic categories:

What types of dental crown material are available?

All-resin dental crowns are less expensive than other crown types. However, they wear down over time and are more prone to fractures than porcelain-fused-to-metal crowns.

What are the steps and preparation?
The preparation for tooth on dental crown usually requires 2 to 3 dentist visits, the first step involves examining and preparing the tooth, the second visit involves placement of the permanent crown

On the first visit
At the first visit, we (Bangkok Smile Dental Clinic) may take a few X-rays to check the roots of the tooth receiving the crown and surrounding bone. If the tooth has extensive decay or if there is a risk of infection or injury to the tooth's pulp, a root canal treatment may first be performed.
Before the process of making your crown is begun, we (Bangkok Smile Dental Clinic) will anesthetize (numb) your tooth and the gum tissue around the tooth. Next, the tooth receiving the crown is filed down along the chewing surface and sides to make room for the crown. The amount removed depends on the type of crown used (for instance, all-metal crowns are thinner, requiring less tooth structure removal than all-porcelain or porcelain-fused-to-metal ones). On the other hand, a large area of the tooth is missing (due to decay or damage). We (Bangkok Smile Dental Clinic) will use filling material to "build up" the tooth to support the crown.
After reshaping the tooth, we (Bangkok Smile Dental Clinic) will use impression paste or putty to make an impression of the tooth to receive the crown. Impressions of the teeth above and below the tooth to receive the dental crown will also be made to make sure that the crown will not affect your bite.
The impressions are sent to our in house dental laboratory where the crown will be manufactured. If your crown is made of porcelain, we (Bangkok Smile Dental Clinic) will also select the shade that mostly matches the color of your neighboring teeth. During this first office visit we (Bangkok Smile Dental Clinic) will make a temporary crown to cover and protect the prepared tooth while the crown is being made. Temporary crowns usually are made of acrylic and are held in place using temporary cement.
On the second visit

At your second visit, we (Bangkok Smile Dental Clinic) will remove your temporary crown and check the fit and color of the permanent crown. If everything is acceptable, a local anesthetic will be used to numb the tooth and the new crown is permanently cemented in place.

Looking after the temporary crowns before the real crowns is place
On temporary dental crowns are just that – a temporary fix until a permanent crown is ready, we (Bangkok Smile Dental Clinic) suggest that a few precautions be taken with your temporary crown. These include:

What problems could develop with a Dental Crown or Dental Caps?

Allergic reaction. Because the metals used to make the crowns are usually a mixture of metals, an allergic reaction to the metals or porcelain used in crowns can occur, but this is extremely rare. Please inform us if you have allergy with any metal before.

Dark line on crowned tooth next to the gum line. A dark line next to the gum line of your crowned tooth is normal, particularly if you have a porcelain-fused-to-metal crown. This dark line is simply the metal of the crown showing through.

 How Long Do a Dental Crowns Last?

On average, dental crowns last between 10 and 15 years. The life span of a crown depends on the amount of "weariness and tearing" the crown is exposed to, how well you follow good oral hygiene practices, and your personal mouth-related habits (you should avoid such habits as grinding or clenching your teeth, chewing ice, biting your fingernails and using your teeth to open packaging).
Types
In the past, gold was the most popular material used for fabricating crowns. Today, it is largely replaced by more aesthetic materials like porcelain. Since porcelain alone is not strong enough, most crowns made of procelain would come with a metal backing. These crowns are very strong, but the metal beneath may show and compromise aesthetics in a demanding patient's front teeth.
In cosmetic dentistry, crowning is also a technique to straighten crooked teeth by first performing elective endodontics, trimming off most of the crooked crown and then rebuilding it in a more aesthetic form. Cosmetic crowns are also usually full ceramic restorations. Examples of ceramics that are very natural-looking and without metal backing are Empress, Procera , Cercon  and most recently, IPS E max.
Strong and beautiful teeth with Procera Crowns what it is?

Procera Crowns is the foundation cap that supports your final dental crown. The fit is important and optimized using modern technology. The material, densely sintered ceramic, makes your new tooth both strong and beautiful, giving you a natural shine between your crown and gum.
 
Procera crowns restore and strenghen damaged or decaying teeth making them appear as completely natural teeth. The superior all-ceramic Procera crown gives you a natural, living look that cannot be acheived with a  traditional crown. With Procera crowns, you don't have to worry about the unsightly dark blue/black lines around the crown margins or the opaqueness of porcelain that tells everyone as soon as you smile that your teeth have been "capped".

Procera crowns are outstanding for their natural appearance and long-lasting strength and durability. They are so "life like" that they are virtually indistinguishable from natural teeth.

Once a decision has been made to place your Procera crown, we (Bangkok Smile Dental Clinic) help you choose the appropriate shading, prep your tooth, and take molds (or impressions) of your mouth. We (Bangkok Smile Dental Clinic) will then carefully custom craft your crown to fit your mouth perfectly. (A temporary crown will be placed until your permanent crown is ready.)

On a return visit, we (Bangkok Smile Clinic) will place your permanent Procera crown, double checking it for appearance and fit. End result? A perfectly blended, natural looking smile.

 Cercon Crowns

Cercon Zirconia is an innovative system for esthetic metal-free crowns and bridges. The reliability of Cercon Zirconia restorations is backed by more than five years of proven clinical success. The system is used to fabricate anterior or posterior single units or multi-unit bridge restorations out of translucent, biocompatible zirconia, the strongest and toughest dental ceramic. Cercon Zirconia restorations can be placed with conventional cementation or adhesive bonding technique.

It is one of the new systems in the manufacture field of porcelain crowns, called Empress, and allows a porcelain crown to be made without the metal understructure. Typically Porcelain Crowns are made by bonding the porcelain to a metal support in a process called Porcelain Fused to Metal (PFM). The drawback is that unlike a natural tooth that allows light to pass through it, the metal support underneath blocks out the light. This can give the crown an opaque and lifeless look. While there previously have been systems for making porcelain crowns that do away with the metal support, most have proven to wear poorly and or break prematurely.
The Empress system, unlike its predecessors, has developed a method of making a Porcelain Crown without metal that is both durable and strong. Since the Crown is made entirely out of porcelain, light is able to pass through just like a real tooth giving a more natural look. However, the Empress Crown is still not as strong as a PFM crown. Therefore, we use PFM crowns on back teeth and for bridgework for the added strength the metal support lends. But for the front of the mouth where esthetics are important, and the teeth do not need to be as strong, Empress Crowns are very effective. In addition, since Empress Crowns are made entirely out of porcelain, there is no risk of having metal edges showing that sometimes appear with PFM if the gum recedes.

E max Crowns is a very new system of crown fabrication which allows a porcelain crown to be made without the metal understructure. Traditionally, porcelain crowns are made by bonding the porcelain to a metal support in a process called Porcelain Fused to Metal (PFM). The drawback is that unlike a natural tooth which exhibits a certain degree of translucency, the metal framework under the porcelain blocks out the light. To the keen observer, the difference in shine and translucency between a natural tooth and a PFM can be quite obvious. While full porcelain crowns (metal free porcelain jacket crowns, PJC) have been done (and are still being done), most have proven to break prematurely. Furthermore, porcelain surfaces are known to wear out opposing natural teeth faster.
With the E max Crowns on the market now, it may be wiser to go for the stronger material. E max Crowns even has an aesthetic advantage over Empress. Being stronger, your E max Crowns can be made thinner than your Empress crown. Thickness is usually a problem in lower front teeth. We (Bangkok Smile Clinic) would definitely recommend E max Crowns for lower front teeth.
If you're unhappy with the opaque, lifeless appearance or the dark line at the margin of your old PFM, you may want to consider changing to Empress Crowns or better still, E max Crowns.
Vectris | Targis Crowns

It is the state of the art restorative materials to fulfill a wide range of requirements.  Today’s patients demand esthetic, tooth colored durable restorations.  Moreover, quality conscious practitioners require materials to be biocompatible and resistant to oral conditions.  They are also interested in the clinical reliability of the materials and in the technical parameters that determine the behavior of the materials in the different indications.

- Vectris Crowns
Vectris Crowns is a prefabricated, light activated, translucent, tooth colored shapeable material made from fiber reinforced composite (FRC). Vectris is composed of a number of layers of fiber bundles. The material is reinforced with the same type of organic polymer matrix contained in Targis (Ceromer).
This matrix assures a strong bond and homogeneously distributes the masticatory force exerted on the Targis material throughout the framework and the entire tooth.
- Targis Crowns
The Targis Crowns is the indirect ceromer system which is a light and heat cured, esthetic, high strength, wear compatible, excellent fitting, bondable posterior crown and bridge, it is inlay and onlay system with or without metal.  Its unique highly filled Ceromer (Ceramic Optimized Polymer) composition provides the esthetics of ceramics with the flexural strength and shade control of a resin.  The Targis Ceromer material combined with the fiber reinforced Vectris material is indicated for bridges crowns inlays and onlays.