Crowns or Caps

Most people have heard about crowns, and several of you may already have one or more. Crowns can be thought of as a new tooth that is custom-made to cover one of your existing teeth. There are various reasons a dentist may recommend that you have a crown or cap put on a tooth. In the vast majority of cases, crowns are placed to protect teeth from breakage (or further breakage). These teeth usually have very large old fillings, and your dentist determines that it is better to cap the tooth than replace the old filling and risk a dangerous fracture. In some cases, the tooth has a crown placed because part of the tooth already broke. Teeth that have had root canal treatment need crowns as soon as possible. Following a root canal, the tooth is brittle and has very little structure left, and can be lost completely if it breaks. Finally, it is rare, but sometimes caps are put on front teeth purely for esthetic reasons. This is usually not recommended; a preferable method would be veneers (see section on veneers). Finally, crowns are used as an integral part of bridges, which are used to replace missing teeth. (see section on bridges) The procedure involves two appointments. In the first, your dentist will "prepare" the tooth/teeth involved, take a mold, place a temporary cap, and send the mold to the laboratory. Then during your second appointment the dentist will cement your finished permanent crown. There are a variety of different options for materials used to make crowns. You will need to consult with your dentist about your case and what is best for you. We will give you an overview of the most commonly used materials and the reasons for their recommended use here.

The gold crown

This is probably the oldest crown in existence due to its simplicity of fabrication. Even today it is still very widely used, and highly recommended by many dentists. Gold is probably the most compatible with your mouth. It is neither too soft nor too hard, and has the ability to fit your tooth with a precision that is unsurpassed. The drawback for a lot of people is that gold is sometimes considered unaesthetic.

The porcelain crown with a metal substructure

This is probably the most widely used crown today, due to its ability to provide great esthetics without compromising durability. The metal substrate is what provides for the strength and durability, and the porcelain covering this base provides the almost undetectable look of a natural tooth. The only disadvantages are that in extremely rare occasions (less than 3%) the porcelain may fracture off. Because of a severe deep bite or small teeth, some patients may not have the amount of space needed to make this kind of a crown, especially if it's a back tooth. In this case, you may need to settle for a gold crown or a partial porcelain one. Your dentist will explain this to you.

The pure porcelain crown

This type of crown would provide you with the ultimate in esthetics. When done properly, it is virtually undetectable from any adjacent natural teeth. This technique is esthetically superior to the porcelain with metal because light can pass through it without resistance, and hence is more "translucent". These crowns were developed to be used on front teeth, but they were considered too fragile to be placed on back teeth where there is more biting force. However, recent advancements in technology have now made it possible to place them on back molars for selected cases. You may want to check with your dentist to see if this is a viable option for you. These pure porcelain crowns are usually " bonded " to the teeth via a very special technique, whereas all other crowns are simply placed on teeth with a traditional type of cement.

Partial crowns

These types of crowns are used in rare circumstances where you may not need a full crown but a filling would still not be suitable. They can also be made of porcelain or gold.

FAQ

Now that my tooth is capped, doesn't it mean it will last forever and that I can never get a cavity on this tooth?

Unfortunately, that is not the case. A cap can never be as great as the tooth nature provided you with, and even that one can get a cavity. In order to extend the life of your crown as long as possible, it is very important that you follow all the proper hygiene instructions provided to you by your dentist. It's true that the gold or porcelain cannot decay, but it must not be forgotten that there is a connection between the crown and the tooth. This joint (that goes all around the tooth ) is very susceptible to decay, and needs your extra attention when flossing and brushing. Otherwise decay can start in this area and move under the crown, which would eventually lead to a root canal or extraction..

I have had a porcelain cap on one of my front teeth for a while, and I can now see an ugly dark line next to my gum line. What is that and is it bad?

The dark line you see is the slight amount of metal that shows up sometimes from under the porcelain covering. If there is no decay, there is really nothing wrong with the tooth or cap. This may develop over the years from brushing the area excessively with a hard brush or possibly from gum disease. You should always use a soft brush and brush gently, especially in this area, as the gums may be very thin .If the looks bother you too much, it would be time to consult with your dentist for a possible new crown. You may even look into a pure porcelain one so the chances of this happening again would be very remote.

My dentist recommended I have a cap on one of my teeth because it has a very large and leaking filling. Why can't I just have another filling put back in the tooth?

Every time an old filling is replaced by a new one, some decay and hence tooth structure must be removed in order to make a clean base for the new filling to be placed. Consequently, if a tooth already has a very large old filling, the new one may simply be too big for the tooth to hold. This would cause undue stress on the tooth, and place it in jeopardy of fracturing. This fracture could cause you to lose the tooth or possibly cause nerve damage, which would necessitate a root canal.