Rebuilding teeth after root canal treatment.

- Dental crowns vs. fillings. / Success rates. / How soon does a final restoration need to be placed?

Links to page: Images | Animations | Slides
Link to why teeth need strengthening slideshow.
Link to restoring teeth after treatment slideshow.
Link to dental research about placing crowns after treatment.

Every tooth will need a final restoration.

After a tooth's root canal therapy has been completed, it will require some type of permanent dental restoration. This page discusses some of the different options that you have.

You may also be interested in these topics:


A) A crown or a filling after root canal - Which is best?

For the most part, the two basic options that you have for restoring an endodontically treated tooth are the placement of a dental crown or else a filling.

Here are some of the issues that need to be considered when choosing between the two.

An access cavity tends to weaken a tooth.

Teeth that have had treatment may require strengthening.

1) The tooth may need strengthening.

Teeth that have had root canal therapy can be fragile, possibly significantly so. That's because:

  • During treatment, a dentist must create an access cavity in the tooth. This can tend to weaken it.
  • Many teeth that require this procedure have already experienced some type of catastrophic event (such as a large cavity or major damage due to fracture).

That means, by the time a tooth's root canal treatment has been completed, a fair amount of its structure may already have been lost. This can place it at risk, even when exposed to normal chewing forces.

As a solution, a dentist will often recommend that a crown should be placed. Dental crowns provide a strengthening effect that can help to prevent fracture.

Coronal leakage - Bacteria seeping past a dental filling.

If contaminates re-enter a tooth, its completed treatment will fail.

2) The tooth requires a proper seal.

If contaminates from the mouth find a way to seep past a tooth's dental restoration (a phenomenon termed "coronal leakage"), its root canal treatment can fail.

A dental crown, more than any other type of restoration, can help to predictably prevent this type of event. (Use the link above for a more detailed explanation.)

3) Restoration longevity / durability.

The final restoration that a dentist places must be one they feel can provide lasting service. The specific physical properties that the restoration needs, however, will vary on a case-by-case basis.

Examples.

a) Relatively intact teeth.

It's possible that a tooth that just has a conservative access cavity and no other history of significant tooth structure loss (such as a previous cavity, filling or breakage) might be successfully restored just with the placement of a dental filling. This approach is probably best suited for anterior (front) teeth.

After its endodontic therapy, this tooth will require a crown.

Teeth exposed to heavy chewing forces should have a crown placed.

b) More involved cases.

In comparison, teeth that already housed a large filling, had extensive decay or had fractured prior to their receiving root canal treatment are probably best restored with a dental crown. (A dental post and core may be required too.)

This approach is often needed for either front or back teeth. Crown placement is especially appropriate for molars, a type of tooth that must be able to withstand heavy chewing forces.

What type of final restoration makes the right choice for your tooth?

Increasingly, placing a dental crown on an endodontically treated molar has become the "standard of care" in dentistry (see below). For other teeth, especially relatively intact front ones, the placement of a dental filling may suffice.

Related page: Can a tooth's existing crown be used after its root canal therapy is finished?


B) Dental research confirms the benefit of dental crowns.

An x-ray showing completed endodontic therapy and a dental crown.

X-ray showing a tooth's completed treatment and dental crown.

Several studies have evaluated the outcomes of teeth that have had root canal treatment and then were, or were not, crowned. Here are the findings of some of those studies.

1) Aquilino (2002) - This study evaluated the track record of 400 endodontically treated teeth and found that those that were not crowned were lost at a rate 6 times greater than teeth that had dental crowns placed.

2) Nagasiri (2004) - This study evaluated 220 molars that did not receive dental crowns after root canal treatment. The survival rates of these teeth at 1, 2 and 5 years were 96%, 88% and 36% respectively.

3) Lynch (2004) - This study evaluated 176 teeth for a three year period following the completion of their root canal treatment. The following survival rates were observed for teeth with the following types of restorations: cast restoration (dental crown) - 92%, amalgam restorations ("silver" filling) - 67%, composite restorations (tooth bonding) - 35%.

Learn about the different types of dental crowns.

Click image to jump to topic Dental Crowns.


C) How soon does the permanent restoration need to be placed?

Your dentist will make a recommendation about the time frame that is appropriate for placing your tooth's final restoration (dental crown or filling).

The phrase "as soon as is reasonably convenient" (meaning not an emergency but definitely a priority), often applies to this situation.

Why the rush?

In general, the temporary restoration that has been placed is just that. Here's why:

  • It can't be relied upon to provide adequate protection or strengthening for the tooth over the long term, thus leaving it at risk for fracture.
  • When compared to a permanent restoration, the seal that a temporary creates isn't as lasting, thus placing the tooth at risk for recontamination.

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