What will become of a tooth's crown after root canal treatment has been completed?

If a hole has been created in a tooth's dental crown so its root canal treatment can be performed, the salient question for most patients simply becomes, will their dental crown need to be replaced or can it still be used? The answer to this question will be based on a couple of different factors, not all of which are completely black and white. They include:

Will the dental crown be capable of protecting the tooth?

Clearly if the structural integrity of the crown has been compromised and the crown can no longer be relied upon to protect the tooth it will need to be replaced. Along this same line, if substantial changes have occurred with the tooth itself (such as the loss of tooth structure that provided a foundation for the crown) a new crown (and possibly even a core or post and core) will need to be placed.

Can the perforated dental crown provide an adequate seal for the tooth?

If it is determined that the structural integrity of the dental crown might be suitable for continued service, the dentist will need to fill in the root canal treatment access chamber with a dental filling. The idea with this approach is that the dental crown provides the strength protection for the tooth. The dental filling patchwork simply plugs the hole that was created.

Each dentist will follow their own protocol as to the manner that they feel constitutes the best repair. From the patient's standpoint, however, it pretty much boils down to the dentist either places a white filling (tooth bonding) or a "silver" one (dental amalgam).

An endodontically treated tooth needs a restoration that can provide an adequate seal.

You might be surprised to learn that the type of restoration a tooth houses can play a significant role in influencing the long-term success of its root canal treatment. The general purpose of root canal therapy is to remove bacteria, debris and irritants from within a tooth. If a substantial seal that can block the seepage of contaminates from the mouth back into the inner aspects of the tooth (this process is termed "coronal leakage") is not established, the success of the root canal treatment will be jeopardized. The difficulty in creating a substantial, lasting, predictable seal would be a major criticism of the crown/filling patchwork solution.

Making a new crown for the tooth provides the most predictable result.

The alternative to patching a perforated dental crown by way of placing a filling is to replace the crown with a new one. In regards to preventing coronal leakage, this solution is probably the most predictable. A well fitting dental crown cemented over a tooth can be expected to provide the best possible seal for a tooth, certainly one that is more substantial and predictable than that created by a crown/filling patchwork solution.

Which is the best solution?

If the amount of time, effort and money involved with placing a new dental crown were of no concern, it seems likely that almost any dentist would recommend that replacing a perforated dental crown with a new one would be the best choice.