Crowns
Crown is the term used to describe the various forms of reproduction of all or part of the visible portion of a tooth. Crowns are used to restore the function, shape and appearance of teeth that have been damaged by dental decay, trauma or use. They are custom made in a laboratory to fit accurately over the prepared tooth.
When teeth have large fillings or root fillings they become weak and prone to fracture. Crowns can strengthen teeth and provide protection from further damage or breakage.
Crowns in various forms have been used to restore teeth for over 150 years but only became commonplace in the 1960s. At that time there were considerable limitations of the choice of materials available to make crowns. The porcelains were weak, needing to be fused to metal to provide sufficient strength and this often resulted in poor appearance. It is unfortunate that many people are unaware of how many improvements have been made in crowns over the last 20 years or so.
Modern porcelains allow crowns to be bonded with polymer adhesives to the tooth and also to be made very strong without compromising the appearance. Skilled dental technicians can reproduce all the complexities of colour and light diffusion of a natural tooth to produce a result that can be indistinguishable from natural tooth.
The choice of material and method of manufacture of crowns depends on the individual tooth and circumstances.
Crowns are most usually provided for damaged teeth. Root canal treatment is not necessarily required prior to providing a crown. Root filled teeth can present particular problems for placement of a crown and may require a retaining post to be inserted into the root, this is known as a post and core or post crown.
Implants require crowns to be placed over them to complete the replacement of the tooth. These crowns can be replaced if necessary at a later date without disturbing the implant.
Crowns may also be linked together with neighbouring crowns in order to fill a space left by a missing tooth. This structure, which comes in many varieties, is known as a bridge.
Crowns may be expected to last at least three or four times longer than fillings provided that they are properly cared for. The crown itself cannot decay but decay can start where the edge of the crown joins the tooth. When this join is hidden below the level of the gumline, daily flossing is essential to remove the plaque that will inevitable accumulate in this area.
Frequently asked questions
You can always tell when teeth have crowns on them can’t you?
No. Modern porcelain technology allows us to provide crowns in most situations that are indistinguishable from natural teeth. However, use of inappropriate materials or very extensive previous damage to the tooth may make it impossible to completely camouflage the problem with a crown.
I’ve heard that crowns often fall out.
Crowns fall out only if they are the wrong shape for your bite or if the underlying tooth either breaks or becomes decayed. Careful planning of the crown and thorough cleaning can avoid both of these problems.
I don’t have to worry about the teeth that have crowns any more do I?
Unfortunately crowns need more care and attention than natural teeth. The most common reason for failure of a crown is decay occurring around the area where it joins the tooth.
Do I have to have a root filling before a crown is put on my tooth?
No, only in exceptional circumstances. A crowned tooth with a healthy nerve inside will last much longer than a tooth with a root filling.
Are crowns very expensive?
The initial cost of crowns is high but because they can last so much longer than fillings they represent a cheaper solution to repairing teeth in the long term.
Should I have all my teeth crowned to protect them?
No. Crowns should only be provided in situations where a filling cannot restore the tooth to proper function or where the filling is so large that the tooth is vulnerable to further damage and requires additional protection.
Will I be able to feel the crowns on my teeth?
When first fitted crowns can often feel unfamiliar. Closely fitting crowns, cemented or bonded to the tooth with a correctly adjusted bite should feel the same as natural teeth.
Now I have crowns do I have to be careful what and how I eat?
During the preparation stages it may be necessary to restrict your diet to soft foods temporarily. The definitive crowns fitted should be specified to suit the requirements of your bite and no restrictions on diet should be necessary. Chewing pens, hairpins and other hard objects is discouraged whether or not you have crowns.