What is a crown and how is it made?
A crown or cap is like a shell that fits over the tooth it is cemented or bonded into place Crowns are an ideal restoration for teeth, which have been broken, or have been weaken by decay or by placing a very large filling. Root treated teeth may require a crown to protect the remaining tooth.
What are crowns made of?
Crowns are made of a variety of materials and new materials are constantly introduced on the market. Different materials are used for different procedures.
Gold has been a commonly used material for crowns, though its appearance often precludes its use in the front if the mouth.
Porcelain bonded to precious metal crown is made of a precious metal base and porcelain is then applied in layers over the base.
Porcelain crowns can be manufacture to give a tooth- like appearance. They are hand crafted by a dental technician to give characteristics to match the other teeth in your mouth. Porcelain can be crafted to give a high degree of translucency, but because porcelain is inherently a brittle material, sometimes a metal sub-frame will be produced usually made of gold alloy, to increase the strength of the crown. We do not use Nickel –containing alloys.
Porcelain and composite crowns- these crowns are made of a resin material and can look very natural. They are not as strong as bonded crowns and are used as a” long term” intermediate solution for full mouth reconstruction cases.
These crowns help the patient to get used to repositioning of the bite.
Gold and Precious metal crowns- Gold and palladium crowns are very strong and hard wearing and are usually used at the back of the mouth. They are nor visible and most suitable for people who grind and clench their teeth.
How is a crown made?
The tooth will be prepared to the ideal shape of the crown. This will involve removing most of the outer surface of the tooth leaving a core. The thickness of the crown will be the same as the amount of tooth that has been removed. Crowns are usually made over 2 appointments which are 2 – 3 weeks apart. It may also require an appointment at the laboratory.
Once the tooth is shaped an impression of the prepared tooth will be taken and one of the opposite jaw and another to mark the way you bite. All the impressions will be sent to the technician to reproduce a crown that fits the tooth. A visit to the laboratory will be needed to match the colour of the crown to the existing teeth. The prepared tooth will have a temporary crown fitted until the new crown is ready.
How long will a crown last?
The life of a crown depends on how much pressure is applied on the bite and how well it is looked after. The crown can not decay, but decay can start where the edge of crown joins the tooth. It is very important to keep the gums and crown clean.
How does the dentist make a crown?
The usual procedure for fitting a crown involves shaping the tooth under local anaesthetic and then taking an impression using a rubberlike material. The impression is then sent to the laboratory along with the details of the shade to be used, where the technician makes the crown.
What happens to my teeth whilst the crown is being made?
While your crown is being made, the prepared tooth can be protected with a temporary crown, which is easily removed just before fitting the permanent one. In most cases, the temporary crown is in place for about two weeks later.
What are crowns made of?
There are different types of crown, the most popular being ‘white’ or tooth coloured. These are usually made entirely of porcelain, which can be quite thin and ideal for the front teeth. They can also be made of porcelain bonded to precious metal, which is much stronger and ideal for back teeth.
Crowns can also be made from metal alloy. gold crowns are suitable for back teeth, where they need to be strong enough to stand up to heavy chewing pressure, but appearance is often not so important. Gold crowns have the advantage of being made very thinly and are often used on teeth that bite together particularly closely.
The latest crowns are made from castable glass. They are very natural looking and are stronger than pure porcelain, but not as strong as porcelain bonded to precious metal.