If your tooth is damaged but not lost, a crown can be used to restore its shape, appearance and function. You may need a crown if you have a root canal, a large filling in a tooth or a broken tooth.
A crown, also called a cap, is a hollow, artificial tooth used to cover a damaged or decayed tooth. The crown restores the tooth and protects it from further damage. Crowns can also be used to cover a discoloured or misshapen tooth. A tooth that has been fixed with a crown looks and works very much like a natural tooth.
How a crown is done
- Your dentist gives you a local anesthetic.
- To make room for the crown, your dentist files down the tooth that needs to be restored.
- An impression of the filed-down tooth and nearby teeth is taken. This impression is used to custom make your final crown. The crown is built using restorative material (material used for fillings) based on the impression. The final crown will be the right shape for your mouth.
- Until your final crown is ready, your dentist places a temporary crown over the tooth that needs to be restored.
- On your next visit, your dentist takes off the temporary crown and puts on the final one. Your dentist checks to make sure the crown is the right fit, shape, colour and bite.
These are the steps dentists most often follow in making a crown, but your tooth may need special care. You may need orthodontic treatment, gum treatment or root canal treatment. It may take more than 2 visits to your dentist, or your visits may last longer.
Different types of crowns
Crowns are made from various types of materials. Depending on which tooth needs a crown, your dentist will suggest a material, or combination of materials, that is right for you.
Metal crowns are made of gold. They generally last a long time and won’t chip or break. They tend not to wear down your opposing natural teeth. However, the gold colour does not look natural, particularly on front teeth.
Composite crowns look natural. They won’t chip as easily as porcelain crowns, but they tend to wear more quickly from chewing. Tooth brushing tends to remove the highly polished surface of composite crowns and this causes them to stain more easily.
Porcelain crowns look the most natural. They are more brittle than metal or composite and may chip more easily. Because of this, they are not usually placed on back teeth.
Porcelain-fused-to-metal crowns look natural and are stronger than porcelain or composite crowns. They won’t chip as easily as porcelain or ceramic crowns. However, depending on their design, the metal may show if your gums are thin or shrink.
Zirconia Crowns are stronger than porcelain crowns. No metal parts are used in this type of crowns so it has a very natural look.
What else should I know?
Crowns are strong and generally last for about 10 years or longer if you take good care of them. Brush and floss your crown, just like you clean your natural teeth. Crowns may not be as strong as your natural teeth. So like your natural teeth, remember not to bite down on hard objects or use your teeth to open or cut things.
Caps or crowns are used in cases where none of the other procedures will be effective or if the tooth structure has been seriously undermined. Crowns have the longest life expectancy of all the possible cosmetic restorations. Cambie Marine Gateway Dental team can recommend the best type of restoration for your particular needs.
Replacement of Old Dental Crowns
The average life of a dental crown is between five and fifteen years, although your dentist will strongly recommend good dental hygiene habits to prolong the life of your dental crown. Many dentists expect the crown to last 10 years or longer. Depending on what wear and tear the dental crown is exposed to, and how well you keep the tooth to which it is cemented free of dental plaque, a crown can last somewhat indefinitely. This is especially true for dental crowns found in a location where its cosmetic appearance is not much of a concern, like the molars.
There can be a variety of reasons why a dental crown might need to be replaced. Some of them are:
1-The Formation Of Tooth Decay
While a dental crown cannot decay the tooth on which the crown is cemented on can. If dental plaque is allowed to accumulate on a tooth in the region where the crown and tooth meet, a cavity can start. The worst-case scenario for your dental crown is that in order for your dentist to be able to get at the decay, and subsequently restore your tooth properly, the crown will need to be removed and replaced with a new one.
2-The Dental Crown Becomes Excessively Worn
Dental restorations are not necessarily more wear resistant than your own natural teeth, nor is it in your best interest that they should be. The ideal dental crown would be one made out of a material that has the same wear characteristics as your own teeth. This way neither the dental crown nor your teeth would wear each other excessively. The most wear-resistant dental crowns are those made of metal, particularly gold alloy dental crowns. For people who clench and grind their teeth excessively (bruxism), dental crowns are at a higher risk of wearing out. A dentist will sometimes detect a small hole on the chewing surface of a dental crown in that area where it makes contact with an opposing tooth (meaning a tooth which touches on the crown when you bite). In these cases, since the crown no longer seals over your tooth your dentist will probably recommend that a new crown be made, before that point in time when dental plaque has seeped under the crown and has been able to start a cavity.
3-The Dental Crown Has Broken
Dental crowns can break, or more precisely the porcelain component of a dental crown can fracture, for those with porcelain dental crowns, or porcelain fused on metal dental crowns. Some dental crowns are made in a fashion where their full thickness is porcelain. In these cases if the crown breaks it will most likely break through and through. Even if the broken piece of the crown doesn’t come off, the aesthetics, function, or the seal of the crown will most likely have been compromised and the crown will need to be replaced. For porcelain fused to metal dental crowns, the dental technician first makes a thin metal shell that fully covers over the affected tooth. A layer of porcelain is then fused to this metal so to give the crown a tooth-like color. In cases where this type of crown has broken it is the layer of porcelain that has fractured off, usually revealing the metal tooth covering underneath. While the function and aesthetics of the crown may have been compromised, the crown’s seal over the tooth may not have been affected. Since the seriousness of a dental crown fracture can vary greatly. Your dentist should evaluate any crown that has broken immediately. Some minor damage might not be of much concern, and possibly ameliorated by a little smoothing with a dental drill, but only your dentist should determine this and only after they have had an opportunity to examine your precise situation.
4-The Crown Has Become Less Aesthetically Pleasing
Some dental crowns are replaced because, from a cosmetic standpoint, their appearance is no longer pleasing. Two situations where the cosmetic aspects of a dental crown can change with time are:
i) The dental crown’s edge has become visible and appears gray
As time passes, the gum line of a tooth on which a dental crown has been placed will recede. This is especially likely in those cases where diligent brushing and flossing have not been practiced. If enough recession occurs the edge of the dental crown, which was originally tucked out of sight just under the gum line, will become visible and appear as a gray line. This is particularly true for porcelain fused on metal dental crowns.
ii) The color of the dental crown no longer matches its neighboring teeth
As years have elapsed, the color of the crown no longer closely matches the shade of its neighboring teeth. In these cases it is not the color of the porcelain used to make the dental crown that has changed but instead the neighboring teeth have stained and darkened. The solution to this problem can be: (i) Replacement of the dental crown with a new one that more closely matches the current color of its neighboring teeth; and (ii) Using a teeth whitening process to return the neighboring teeth closer to the color they were when the dental crown was originally placed.
For the majority of individuals with dental crowns, replacing them is an inevitable task. With proper teeth maintenance and good dental hygiene practices, you should be able to maximize the life of your dental crown. However, if there are any problems to your dental crown, you should contact your dentist immediately for evaluation. Advancements in the dental crown production and technologies are being made, so by the time you do need to replace your dental crown, your dentist will be able to inform you of all the latest options available, and recommend the best options that are optimal for you.