How are crowns used in root canals?

Root canal therapy involves the removal of the pulpal tissue (the nerve, blood vessels, etc.) located inside the tooth.  The area is cleansed and then filled to seal the canal.  After the root canal is complete the tooth will need to be properly restored.  Often if the root canal is done on a front tooth you may only require a filling.  But usually on a back tooth the tooth will require a crown to properly restore it.  The back teeth are used for most of our chewing and need the strength of a crown to prevent them from breaking after a root canal is done.

A crown is a separate procedure from a root canal.

Root canals are done to treat infection. Crowns are used to reinforce weak teeth.

There are times when you have a root canal and don't need a crown.

There are times when you have a crown and don't need a root canal.

Most of the time, a lot of tooth has been destroyed by a cavity that infects the nerve. The root canal takes care of the infection, and the crown takes care of the large amount of damage done by the cavity.

Crowns are sometimes indicated following a root canal for several reasons.  When a tooth has extensive decay (cavity) that has infected the nerve space, root canal therapy is often indicated to remove the infection. It is necessary to remove the affected tooth structure(decayed area) along with removing the infected nerve.  By doing this much of the tooth structure used for chewing must be removed.  In order to replace the lost structure a crown could be indicated.  It is also important to seal the root canal space with a restoration to decrease the likelihood of further infection. Furthermore, when a root canal is completed the organic component of the tooth has been lost, making the tooth more brittle.  A crown returns some of the structural strength back to the tooth.  The analagy I use is: you have a tree that has died.  It is still standing, but it has lost the organic component that keeps it from breaking under the force of a storm.  It is brittle and more likely to break.  A crown decreases the chances of the tooth breaking after a root canal like the dead tree.

When a tooth undergoes root canal treatment the decayed tooth structure and infected nerve is removed along with its blood supply. As a result, the remaining tooth structure is usually a thin shell and can become very brittle, which puts it at a high risk for fracture. In order to be able to use the tooth in function and prevent the tooth from fracturing it is important to cover the root canal treated tooth with a crown. 

Binod Verma

Crown is a complete coverage of tooth which is done as follows -

The tooth is reduced in its diameter about 1.5 mm all around and the complete coverage can be done two ways -

  • Direct technique - Cad CAM technique, the crown is fabricated with the 3D images of the prepared tooth from a porcelain block. This can be done either in the office or the office sends the image of the prepared tooth to the lab and the lab fabricates the porcelain crown.
  • Indirect technique - The dentist prepares the tooth for crown and takes an impression of the prepared tooth and sends it to lab for fabrication of the crown.

Now depending on the needs of the patient the dentist asks the lab to fabricate a coping of the tooth which can be in metal or none metal. Once the coping fits well on the patient's tooth, the coping is bonded to porcelain on the outer surface.

So the crown can be made with all porcelain, porcelain fused to metal (precious, non precious, semi-precious), all metal crown (only used for the back tooth due to aesthetic reason and can be made of precious, semi-precious or non precious metal).

Following a root canal, the remaining tooth does not have a blood supply so it becomes brittle. A crown is used to cover the tooth; this can prevent the fracture of the tooth and it restores its normal anatomy. At times crowns are needed because the decay or fracture that lead to the root canal has destroyed too much of the tooth structure to be able to function effectively.

If you have had a root canal treatment in a molar or premolar (a back tooth) you almost always need a crown. A crown strengthens the tooth to prevent it from cracking. After root canal treatment the tooth is weak from the large hole in it.

Because our teeth are "V" shaped on the biting surface, when we bite down our teeth flex toward our cheeks and tongue. Over time this flexing causes cracking in the tooth. 

A crown acts like a splint. It prevents these flexing motions and therefore the cracking. It also provides the best seal from bacteria to protect the root canal system and treatment.

A crown is often used after a root canal to protect the treated tooth. A root canal essentially hollows out and then fills the tooth, which makes it much weaker than it would be naturally. Hence a crown to protect it.

Most teeth that have root canal treatment have prior restorative dentistry. In most cases, the old restorations are removed to make sure all decay is taken care of, then depending on the amount of remaining tooth structure, a core build up with or without a post, depending on the dentist's assessment will be done to prepare a sound infrastructure for a crown. A crown then will completely cover the remaining tooth and is cemented in place. This will seal the tooth from bacteria and provide support for function. Root canal teeth with large fillings instead of crowns are more likely to fracture.

A root canal procedure removes the blood vessels as well as the nerve from the tooth. Having no nutrients from blood vessels causes the tooth to become brittle and prone to fracture.  A crown surrounds the tooth to strengthen it. Most posterior teeth need crowns after root canals. Anterior teeth that have large cavities or fractures also need crowns after root canals.

Crowns are placed on teeth following root canals to protect them from further injury. Most likely, the tooth already was severely damaged which necessitated the root canal in the first place. The crown also restores the function of the tooth and will make it more cosmetically acceptable.

After the root canal is completed a crown may be recommended because the tooth is structurely weak. A crown goes over the tooth after it is shaped by the dentist and increases the strength of the tooth.
Once a tooth has had a root canal, it becomes more fragile. Furthermore, the tooth may have had extensive decay/cavity and fillings prior to the root canal, leaving little healthy structure. A crown surrounds the remaining tooth structure to reinforce it so one can chew normally.
A crown is commonly, but not always, recommended to restore a weakened tooth. Many times a tooth that has had a root canal also had a large filling, or crack, or other condition that has weakened it, and therefore a crown is the restoration of choice. In a few cases the need for the root canal was due to a cause that has left most of the tooth structure intact, and in those few cases a crown may not be needed. Your dentist will make a recommendation based on your individual situation.
Romesh Nalliah

Root canal treatment is excellent because it enables you to keep your tooth after a tooth abscess. However, after root canal treatment you are left with a "dead tooth". A dead tooth can be darker, and more brittle than a normal tooth which makes it more prone to fracture.

These two concerns can be addressed by using a crown after root canal treatment. A crown covers over the whole tooth and restoration and prevents any crown fracture. It also covers over a darkened tooth and can be made using porcelain to look like a normal healthy tooth.

A tooth that needs root canal may have lost a sizable portion of its structure due to existing decay and removal of tooth structure for the dentist to perform the procedure. Therefore a tooth that had a root canal structural integrity may be compromised.

A crown (cap) which surrounds a compromised tooth adds support and protection from the forces when you bite down. Without a crown a root canal tooth can fracture and need to be removed.  

If a tooth that had root canal has most of its structure remaining, then a crown usually is not necessary since there is sufficient tooth structure.

Crowns are used after your root canal is finished to help protect your tooth from fracturing or splitting. A root canal removes the nerve and blood supply to your tooth, meaning that the tooth is no longer receiving nutrients. This can make it easier for your tooth to break.

Think of it like the leaves of trees. In the Fall, when the leaves stop getting nutrients, they change color, and eventually become dry and brittle, easily able to be crushed in your hand, leaving only "leaf dust".

A crown fits all around the top part of your tooth and makes it harder for the tooth to flex or move during chewing. 

Once a tooth has had root canal treatment done, it has had its nerve and blood supply removed from it. As a result over time it has a tendency of getting more brittle and less flexible. So it is very important once the tooth is asymptomatic for it to be restored by placing a crown on it. The crown protects the tooth from further fractures and deterioration.

A crown may be indicated after root canal therapy. Crowns protect root canaled teeth. They prevent the leakage of bacteria from your mouth from entering the tooth canal, where the nerve originally resided. They also prevent the breaking of teeth after therapy. To perform a root canal, the dentist will make a hole in the tooth to clean out the infected nerve. This inherently makes the tooth weaker. The crown will cover and protect the tooth. Not all teeth may need a crown after therapy. For example, some front teeth that did not have previous fillings may not need one. Most back teeth will need a crown because that is where most of the chewing occurs. You will need to discuss with your dentist whether or not a crown after therapy is right for your particular situation.

A crown, or cap, is often indicated to provide a stronger, more secure restoration following root canal treatment. This helps prevent fracture of the tooth, which has often been weakened by decay and/or extensive fillings. The crown surrounds the weakened tooth structure, acting as a type of "splint" to help hold the tooth together.
After the infected or decaying pulp has been cleared from inside a tooth during a root canal, the opening at the top of the tooth needs to be covered to prevent further infections. The cleared out portion of the tooth is filled with a special inert material, which is then covered with a dental cement. A custom crown shaped like a normal tooth and made from gold or porcelain is then placed over the top of the tooth (sometimes anchored with a post inserted into the dental cement), allowing normal use of the tooth.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.