Crowns
Crowns are an ideal restoration for teeth, which have been broken, or have been weakened by decay or a very large filling. The crown fits right over the remaining part of the tooth, making it strong and giving it the shape and contour of a natural tooth. Crowns are sometimes also known as 'caps'.
Why are crowns used?
There are a number of reasons. For Instance:
the tooth may have been weakened by having a very large filling
you may have discoloured fillings and would like to improve the appearance of the tooth.
you may have had a root filling which will require a crown to protect it.
What are crowns made of?
Crowns are made of a variety of materials, and new materials are continually being introduced. Here are some of the options available at present:
Porcelain bonded to precious metal: This is what the majority of crowns are made from. A precious metal base is made and porcelain is then applied in layers over it.
Porcelain: These crowns are not as strong as bonded crowns but they can look very natural and are most often used for front teeth.
Porcelain and composite: Porcelain and composite resin materials can sometimes look the most natural. However, these crowns are not as strong as bonded metal crowns.
Glass: These crowns look very natural and are used on both front and back teeth.
Precious metal (gold and palladium): These crowns are very strong and hard wearing, but are usually used at the back of the mouth, where they are not visible.
How is the tooth prepared?
The dentist will prepare the tooth to the ideal shape for the crown. This will involve removing most of the outer surface, and leaving a strong inner 'core'. The amount of the tooth removed will be the same as the thickness of the crown to be fitted. Once the tooth is shaped, the dentist will take an impression of the prepared tooth, one of the opposite jaw and possibly another to mark the way you bite together. The impressions will be given to the technician, along with any other information needed to make the crown.
Who makes the crown?
The impression and shade information will be given to a Dental Technician who will be skilled in making crowns. Models will be made of your mouth and the crown will be constructed on these in order to ensure that the crown fits perfectly.
Will the crown be noticeable?
No. The crown will be made to match your other teeth exactly. The shade of the neighbouring teeth will be recorded, to make sure that the colour looks natural and matches the surrounding teeth. A temporary crown, usually made in plastic, will be fitted at the end of the first appointment to last until the permanent one is ready. These temporary crowns may be more noticeable, but they are only a temporary measure.
How long does the treatment take?
At least two visits are needed, the first for the preparation, impression, shade taking and fitting the temporary crown, and the second to fit the permanent crown.
Does it hurt to have a tooth prepared for a crown?
No. A local anaesthetic is used and the preparation should feel no different to that of a filling. If the tooth does not have a nerve, and a post crown is being prepared, then local anaesthetic may not be needed.
Are post crowns different?
Post crowns may be used when the tooth has been root filled. The weakened crown of the tooth is drilled off at the level of the gum. The dentist makes a double-ended 'post' to fit into the root canal. This can be either prefabricated Stainless Steel or custom made of gold. One end of the post is cemented into the root canal, and the other end holds the crown firmly in place.
Are there any alternatives to post crowns for root-filled teeth?
If a root-filled tooth is not completely broken down, it may be possible to build it up again using filling material. This 'core' is then prepared in the same way as a natural tooth and the impressions are taken.
How long will a crown last?
The life of a crown will depend on how well it is looked after. The crown itself cannot decay, but decay can start where the edge of the crown joins the tooth. It is very important to keep this area as clean as your other teeth, or decay may occur which could endanger the crown. Properly cared for crowns will last for many years - your dentist will be able to advise you how long.
How are crowns fixed to teeth?
Once the fit and appearance of the crown has been checked - and approved by you - it will be cemented in place with special dental cement. The cement also forms a seal to help hold it firmly in place.
Will the crown feel different?
Because the shape of the crown will be slightly different from the shape of the tooth before it was crowned, you may be somewhat aware of it to begin with. Within a few days it should feel fine, and you will become unaware of it. The crown may need some adjustment if it feels proud of the surrounding teeth. If it is at all uncomfortable you should ask your dentist to check and adjust it.
BRIDGES & DENTURES
Why should I replace missing teeth?
Your appearance is one reason. Another is that the gap left by a missing tooth can mean greater strain is put on the teeth on each side. A gap can also mean your 'bite' is affected, because the teeth next to the space can lean into the gap and alter the way the upper and lower teeth bite together. This can then lead to food getting packed into the gap, which causes both decay and gum disease.
How are missing teeth replaced?
This depends on the number of teeth missing and on where they are in the mouth. The condition of the other teeth also affects the decision.
There are two main ways to replace the missing teeth. The first is with a removable false tooth or teeth - a partial denture. The second is with a fixed bridge. A bridge is usually used where there are fewer teeth to replace, or when the missing teeth are only on one side of the mouth.
What is a partial dental?
This is a plate with a number of false teeth on it. It may well be all plastic or a mixture of metal and plastic. Both types may have retaining clips (clasps), to help keep the denture in place in the mouth. Depending on where they are, some of these clips may be visible when you smile or open your mouth.
What are the replacement teeth made of?
Usually plastic, and occasionally porcelain. Each replacement tooth is made specially, to get the right shape, colour and size for you.
What is the difference between a plastic partial denture and one that contains metal?
Plastic partial dentures are less expensive to make but unless they are designed very carefully they can damage the teeth they fit against.
Metal partial dentures are usually made from an alloy of cobalt and chromium and they are much stronger. They are lighter to wear and can be supported by the remaining teeth. Although the base is metal, they have gum-coloured plastic and natural-looking teeth fixed to them. They are more expensive than the plastic ones.
How do I choose the best type for me?
Be guided by your dentist. He or she will know the condition of your remaining teeth. In most cases a metal-based partial denture gives the best result, but the higher cost may make you decide against it.
How do I look after my denture?
You should remove the denture from your mouth for cleaning. You'll be shown how to clean it by your dentist or hygienist, probably with a small toothbrush and toothpaste, or by soaking it in cleansing solution. If you have a metal based denture you'll need to choose a cleansing solution that's suitable for metal.
Should I take my denture out at night?
Yes. leave it in water to prevent it warping.
What is the alternative to a partial denture?
The main alternative is a fixed bridge. This is made by constructing crowns on the teeth at either side of the space, and then joining these two crowns together by placing a false tooth in the space. This is all made in the laboratory and then the pieces are cemented into place with special adhesives. The bridge can't be removed.
Can I always have a bridge to replace missing teeth?
Providing you have enough strong teeth with good bone support, yes, you can usually have a bridge. Your dentist will help you decide which is the best way of replacing the teeth within your budget
Are bridges expensive?
Although a bridge may seem expensive it will give many years of use. It will also improve your appearance and bite. A bridge uses the considerable skill of the dentist and technician, and in this way, it's similar to ordering a piece of hand-made jewellery. The materials are also expensive so it's fair to say a bridge will not be the cheapest treatment you have ever had.
How do I look after my bridge?
You need to clean your bridge every day, to prevent problems such as bad breath and gum disease. You also have to clean under the false tooth every day. Your dentist or hygienist will show you how to use a bridge needle or special floss, as a normal toothbrush cannot reach the area.
Are there other methods for fixing false teeth?
There are other methods, such as using a combination of crowns and partial dentures that can keep the retaining clips out of sight. These are quite specialised dentures, so you should ask your dentist about them.
Can I have teeth which attach to the jawbone?
This is possible with the use of implants. The success of this technique means you may be able to replace missing teeth without crowning other teeth. Our leaflet on implants explains this in detail.
Remember that it's as important to care for your remaining teeth as it is to replace the missing ones.
1.Space left by missing tooth.
2. The teeth are prepared.
3. The bridge is bonded into place.
4. The natural smile is restored.
VENEERS
What is a veneer?
A veneer is a thin layer of porcelain made to fit over the front surface of a tooth, very much as a false fingernail fits over a nail. Sometimes a natural colour 'composite' material is used instead of porcelain.
What are the advantages of veneers?
Veneers make teeth look natural and healthy, and because they are very thin and are held in place by a special strong bond (rather like super-glue) very little preparation of the tooth is necessary.
When would I need a veneer?
Veneers can improve the colour, shape and position of teeth. A precise shade of porcelain can be chosen to give the required colour, to improve a single discoloured or stained tooth or to lighten front teeth (usually the upper ones) generally. A veneer can make a chipped tooth look intact again - the porcelain covers the whole of the front of the tooth with a thicker section replacing the broken part. Veneers can also be used to close small gaps, when orthodontics are not suitable. If one tooth is slightly out of position, a veneer can sometimes be fitted to bring it into line with the others.
What about alternatives?
A natural coloured filling material can be used for minor repairs to front teeth. This type of restoration is excellent where the tooth supports the filling, but may not work so well for broken tooth corners. There will always be a join between the tooth and filling material.
Crowns are used for teeth which need to be strengthened - either because they have broken, have been weakened by a very large filling, or have had root canal treatment.
How long will a veneer last?
Veneers should last for many years, but they can chip or break, just as your own teeth can. Your dentist will advise you how long each individual veneer should last. Small chips can be repaired, or a new veneer fitted if necessary.
How are teeth prepared for a veneer?
Some of the shiny outer enamel surface of the tooth may be removed, to ensure that the veneer can be bonded permanently in place later. The amount of enamel to be removed is minimal and will be the same as the thickness of the veneer to be fitted, so that the tooth remains the same size. A local anaesthetic (injection) may be used to make sure that there is no discomfort, but in many cases this is not necessary. Once the tooth has been prepared, the dentist will take an 'impression'. This will be given to the dental technician, along with any other information needed for him to make the crown. The colour of the surrounding teeth is matched on a shade guide to make sure that the veneer will look entirely natural.
How long will it take?
A veneer takes at least two visits, the first to prepare the tooth and to match the shade, and the second to fit it. Before bonding it in place, your dentist will show you the veneer on your tooth to make sure you are happy with it. Bonding a veneer in place is done with a special adhesive, which holds it firmly on the tooth.
Will I need a temporary veneer between visits?
Because the preparation of the tooth is minimal, you will probably not need a temporary veneer. The tooth will look very much the same after preparation, but will feel slightly less smooth.
What happens after the veneer is fitted?
Only minor adjustments can be made to the veneer after it is fitted. It is usually best to wait a little while to get used to it before any changes are made. Your dentist will probably want to check and polish it a week or so after it is fitted, and to make sure that you are happy with it.