Dental posts and cores.

- What is a "core" vs. "post and core"? / When is each needed? / The placement procedure. / Prefabricated vs. cast. / How long does a post and core last? / Costs.

Page Graphics | Animations.
Link to Post and Core Placement slideshow.
Link to Why a Core is Needed animation.

1) After your tooth's root canal treatment has been completed, your dentist may recommend the placement of a dental crown.

2) In some instances, they may also inform you that a dental post and core (or else just a core without a post) must be placed before the crown can be made.

This page explains:


A) What is a "core"?

Teeth sometimes have large portions missing due to decay, fracture, the loss of a filling or the creation of an access cavity (the hole through which root canal work is performed).

Cores.

Core placement refers to a procedure where a dentist replaces the bulk of a tooth's missing structure in preparation for making a new dental crown. Doing so creates the optimal shape and foundation for the new restoration.

What materials are used?

A core can be made out of any type of permanent dental restorative. In most cases it's either: 1) Dental amalgam (the metal used to make "silver" fillings) or else 2) Dental composite (the dental bonding used to make "white" fillings).

Dental cores aid crown stability.

A core replaces lost tooth structure that's needed for crown stability.

Why is a core needed?

Background.

A great deal of a crown's stability depends on the amount of tooth structure that extends up into its interior. If very little tooth structure fills this space, the crown will be easily dislodged, especially by forces directed from the side.

What a core does.

By "building up" the tooth first with a core (rebuilding the tooth so it is closer to its original dimensions), the dentist can greatly increase the stability of the crown, and therefore maximize its long-term chances for survival.

B) What is a "post and core"?

The difference between a dental core and a post and core is that with the latter, a dental post is placed that helps to anchor the core to the tooth.

While a dental core can be created for any tooth, a post and core can only be made for a tooth that has had root canal treatment.

X-ray of tooth that has a post & core and dental crown.

An x-ray image of a dental post and core.

The post is positioned in the tooth's root. It's attached core extends up inside the tooth's crown.

Is a post always needed?

As general rules of thumb:

  • If more than half of a tooth's original crown portion (the part of the tooth normally visible above the gum line) has been lost, a post is needed to assist with anchoring the core to the tooth.
  • If more than half of the tooth's crown still remains, a core by itself will probably suffice.

Posts don't strengthen teeth.

In decades past there was a misconception that metallic dental posts played a role in reinforcing (strengthening) the teeth in which they were placed.

To the contrary, dental research has since shown that these posts offer no reinforcement benefit and, in fact, can actually weaken teeth and place them at risk for fracture. (Raedel 2015)

Heydecke (2001) reported that case failures not involving situations where a post had been placed were more likely to be "repairable" (procedures could be performed where the damaged tooth could still be salvaged).

[page references]

Research findings.

As evidence of this we'll mention a study by Willershausen (2005) which evaluated 775 endodontically treated (root canalled) teeth.

  • It was determined that as a group these teeth had a complication rate of 6.6%. (This included events such as root fracture.)
  • In comparison, a subgroup composed of just those teeth having metal posts had a complication rate of 13.2% (twice as high).

These findings aren't meant to suggest that post placement is a "bad thing." However, a dental post should be recognized as just an aid in helping to anchor a dental core to its tooth. If enough natural tooth structure still exists, then no post is needed and for good reason should not be placed.


How does a dentist place a dental post and/or core?

a) The dental core procedure.

When placing just a core alone:

  • The dentist will apply dental restorative (meaning filling material, such as dental amalgam or bonding) to the tooth, not unlike when a regular filling is placed.
  • As a part of the process, they may also screw tiny "pins" into the tooth. As the restorative is packed around them, they help to anchor the core in place.
Shaping the core.

The overall goal is to place enough dental restorative that once the tooth has been prepared (trimmed) for its new crown, the resulting tooth and core combination is generally the same size and shape as it would have been if no original tooth structure had been lost.

Placing the post.

Post placement may be required before a dental crown can be placed.

b) The post and core procedure.

When placing a post and core:

  • The dentist will first use their drill to create a "post space." This space will generally lie within one of the root canals that was filled during the sealing portion of the tooth's endodontic treatment.
  • A post, having specific dimensions matched to the post space that's been drilled, is then cemented or bonded into place.
  • Once the post has been secured, dental restorative is packed over and around the post's exposed end so to create the core. (See animation below.)

    Ultimately, the core is anchored in place both by the post and adjacent tooth structure.

Placing the core and shaping the tooth for its crown.

Placement of a crown on a tooth that has a dental post and core.

c) Completing the tooth's reconstruction.

Once the core, or post and core, has been completed, a dental crown can be fabricated for the tooth and placed.

We outline the steps of this process here: How dental crowns are made.

Types of dental posts.

Traditionally, posts have been made out of metal (stainless steel, titanium, cast metal). In today's marketplace, ceramic (zirconia) and carbon-fiber posts are also available.

Flexible vs. rigid.

The flexible nature of carbon-fiber offers the advantage that as a tooth's root flexes under load this type of post will too, thus helping to prevent root fracture by way of reducing the amount of stress directed to it.

However, the bonding technique used to place them is technique sensitive, and thus placing a traditional rigid post using traditional cement may offer the more predictable outcome. (Raedel 2015)

White vs. metal.

The white, translucent nature of ceramic (zirconia) and some types of fiber posts offers an esthetic advantage over metal ones. The dark, opaque nature of metal posts can affect the apparent color of translucent all-ceramic dental crowns. This would be an especially important consideration for front teeth.

Cast-metal vs. prefabricated post and cores.

When placing a metal post, your dentist has the option of using a prefabricated or "cast" one.

A cast post and core is a single object (post and core combined) that is specially made for your tooth in a dental laboratory. Placing one is a two-visit procedure, and typically involves a higher cost (see estimated fees below).

Placing a prefabricated post is the less-expensive, single-visit process that we describe and illustrate on this page.

Studies confirm that both types of post and cores generally offer the same expected survival rates. Jung (2007) reports 90% vs. 94% at 8.5 years. Gomez-Polo (2011) reports 83% vs. 85% at 10 years. (Cast vs. prefabricated respectively.)


How much do post and cores cost?

Here is an estimate of the fee you dentist might charge for the procedures discussed on this page.

  • Core (only).        $194.00 - $345.00
  • Prefabricated post and core.        $243.00 - $425.00

    (A prefabricated post and core is the type described on this page.)

  • Cast post and core.        $284.00 - $495.00

    (A cast post and core is a one-piece unit that is custom made in a dental laboratory and then is cemented in the tooth. Placing one is a two-appointment process. While its construction is different, it serves the same function as a prefabricated one.)

About the fees shown.

Low fee = Small rural city or town.    High fee = Large metropolitan area.
How did we come up with these estimates?

Does dental insurance cover post and cores?

When covered, this procedure is usually categorized as a "major" dental service. As such, benefits typically run on the order of 50% of the procedure's UCR fee. To receive maximum benefits, the policy holder will need to have met their plan's deductible.

If your plan covers dental crowns, it probably covers post and cores too.

Common insurance limitations.

  • Some plans don't cover cores alone (as in without post placement).
  • When covered, these procedures typically carry the same general restrictions that the policy involved applies to dental crowns. This can include waiting periods, age restrictions and limitations on replacement.
  • Coverage for post and cores may be limited in frequency (as in one per tooth per 5-year period).

How much does your dentist pay for a post and core?

There are a lot of procedures in dentistry where the cost of the main item itself only makes up a small percentage of the dentist's overall expenses when performing the service, and thus fee charged. Post and core placement is one of these.

Dental laboratory fees for dental post and cores: (Your dentist's cost.)

  • Cast post and core  -  $20.00 to $35.00
  • Prefabricated post, metal  -  $10.00 to $18.00

How long do post and cores last?

We've cited two studies above that suggest that the survival rate for post and cores lies somewhere on the order of 92% at 8.5 years and 84% at 10 years.

Those numbers are similar to survival rates reported for dental crowns (post and cores are placed in preparation for placing a crown).

How long will your tooth last?

It should be pointed out that crown failure usually does not involve tooth loss, whereas post and core failure more commonly does (like due to complications with root fracture).

One study (Raedel 2015) concluded that on average teeth restored with post and cores survived for 13.5 years (from post insertion to tooth extraction). The study specifically stated that this span was less than reported by other investigations, possibly due to it having included a larger number of "severely damaged" teeth.

Long-term success likely depends on your tooth's initial conditions.

The findings above suggest that when determining the prudence of saving a tooth (via performing root canal treatment and then rebuilding it with a post and core and crown), what technically is possible (dental "heroics") may not equate with making the best choice.

By definition, posts are only placed in teeth where so much structure is missing that a core cannot otherwise be adequately anchored. If your tooth's status is an extreme example of this condition (ask your dentist for their opinion), choosing another route instead (such as dental implant placement, we compare these treatment approaches here) may make the wiser choice.


Related pages about restoring root canalled teeth.

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