Placing A Crown On A Tooth That Has Received A Root Canal
A root canal (RT) is an endodontic treatment performed to save a person’s tooth. In some cases, the pulp tissue of the tooth becomes infected. This often happens when a cavity is allowed to go untreated for an extended period. Decay penetrates the enamel and enters the canal, allowing bacteria to grow. Other times, the pulp tissue may become damaged by trauma. When the damage cannot be corrected, the tooth must be canaled in order to save it.
During the procedure, the pulp tissue inside the affected tooth is removed, and the newly-emptied canal is cleaned. Then, a dental crown is placed in order to seal it. This article will explain the reasons this is done, and describe the process.
What Is A Dental Crown?
A crown is a form of dental restoration. It can be used to improve the appearance of a person’s smile as well as to seal a hollowed out tooth. Crowns are made of various materials, including gold and ceramic, and are fixed into position with a special dental cement.
Why A Crown Is Useful Following A Root Canal
Teeth remain strong as a result of a person’s blood supply. Once this supply is cut off, their strength declines quickly. During root canal therapy, the nerves and blood vessels that deliver blood to the pulp tissue are severed. As a result, the canaled tooth weakens to the point that its structure may begin to develop fractures. It can break apart from an activity as simple as chewing.
After an RT is performed, the empty canal left by the evacuated pulp tissue is filled. A rubber composite called gutta percha is used to fill the space. A post is placed into the filled canal as support, and a crown is placed over the post.
A dental crown is used for two main reasons. First, it seals the canaled tooth, preventing bacteria from gaining access to the pulp chamber and canal. This in turn prevents infection from getting inside.
The second reason is because a crown reinforces the structure of the canaled tooth. As noted above, the tooth is much weaker following endodontic treatment, and becomes susceptible to cracking or breaking apart. By placing a crown over the filled canal, the tooth is strengthened enough to withstand the force placed upon it while chewing.
In some cases, the canaled tooth may be strong enough that placing a crown on it is unnecessary. This is a decision your dentist will make after examining the tooth. If much of its structure has been preserved, a bonding agent may suffice.
How A Root Canal Compromises The Strength Of A Tooth
To understand how endodontic therapy weakens a tooth, it’s useful to be familiar with the process used to treat it. First, the dentist drills into the pulp chamber to remove the connective tissue and nerves. Once both are gone, the space is washed with an antiseptic. Then, it is filled.
The pulp chamber is accessed through a hole drilled into the top of the tooth. While making this hole and the cavity beneath it, the dentist’s drill removes a portion of the inner structure. Sometimes, the amount removed is substantial. This weakens the integrity of the tooth, making it prone to fractures. This is the reason a crown is placed rather than allowing the filling alone to support the tooth.
Placing The Post And Crown
A post is often unnecessary, but can offer additional support for the crown when much of the inner structure of the tooth has been removed. The dentist will cement the post in place. Then, the top of the canaled tooth is trimmed so that it fits seamlessly with the crown. This provides additional stability.
The crown must be fabricated in a lab from an impression taken of the trimmed tooth. This can require up to two weeks during which a temporary crown is worn. Once the permanent crown is ready, it is cemented into place.
A crown is the most effective type of dental restoration for a tooth that has received a root canal. In most cases, it can be expected to last over a decade.