Guide to  Dental Post-and-Cores  and  Core Buildups – Why are they needed?

Cores and Post-and-Cores – What are they? Why are they needed?

When a tooth has been weakened by decay, trauma, or the aftermath of root canal treatment its remaining tooth structure may not be adequate to support the crown that’s needed to rebuild it.

In such cases, a dentist will place a core or a post-and-core buildup to replace the tooth’s missing structure. Doing so creates the ideal foundation for the new crown, enhancing its stability and helping to ensure its long-term success.

This guide explains the differences between core-only buildups and post-and-cores, along with detailing when each option is necessary. It also provides insights into the materials used, cost considerations, and the expected longevity of these restorations. Having these details can help you in making informed decisions about the planning of your upcoming dental care.

Guide to Dental Cores and Post & Cores – What are they? Why are they needed?

A) What is a “core buildup”?

Placing a dental core refers to a procedure where a dentist replaces/rebuilds a large portion of a tooth’s missing or compromised “coronal” tooth structure, typically in preparation for making a dental crown for it.

(Coronal = that portion of the tooth that lies at and above the gum line.)

What is the purpose of placing a core buildup?

Teeth are sometimes missing a large part of their structure due to decay, fracture, the loss of a filling, or as a consequence of creating the access cavity needed for their root canal work. And this reduction in size and shape may not provide a suitable foundation for the tooth’s planned final restoration (crown or dental bridge abutment).

The placement of a core buildup restores a tooth closer to its original dimensions, therefore making it possible for the dentist to achieve a more idealized shape when preparing (trimming) it for its new restoration.

Why is a core buildup needed?

Background.

A great deal of a crown’s retention and stability (meaning how well it stays in place) depends on the amount of tooth structure that extends up into its interior.

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

If not enough tooth structure reaches into this space, the crown will be more easily dislodged by occlusal forces (chewing forces), especially those that have a lateral orientation (at an angle) component.

How a core solves this problem.

By first “building up” a broken down tooth with a core buildup (rebuilding the tooth so it’s closer to its original dimensions), the dentist can greatly increase the stability of the crown.

Once the core has been placed, the dentist has the optimal amount of structure (tooth + core) to work with. When shaping the tooth for its planned crown, they can optimize the degree to which it extends into the crown’s interior, thus improving the restoration’s long-term chances for survival (longevity) to the continual punishment of occlusal forces.

When, precisely, is a core buildup needed?

The need for this procedure is a judgment call made by the dentist about whether enough tooth structure currently exists. However, as a general rule of thumb, cores are typically only placed in situations where one-half or more of the tooth’s coronal tooth structure (the portion of the tooth that lies at and above the gum line) is compromised or missing.

▲ Section references – Shillingburg

What materials are used to make a dental core?

A core can be made out of any type of permanent dental restorative. In most cases, it’s either:

• Dental amalgam – the metal used to make “silver” fillings.
• Dental composite – Composite resin (dental bonding) like that used to make “white” fillings.

(Shillingburg)

How is a core placed?

The process of placing a core is generally the same as when the same materials are used to create a filling for a tooth.

FYI: We explain the process in greater detail on our Core Buildup Procedure page. Jump

Additional FAQ about dental cores.

Is a core buildup the same as a filling?

They are similar and are made using the same kind of dental materials but they each serve a different function.

A core buildup is placed for the specific purpose of allowing the dentist an opportunity to create the ideal foundation for a new dental crown. As such, a core won’t meet many of the criteria a filling must, such as the way it contacts neighboring teeth or teeth that bite against it. (The crown that’s placed over the core will meet these criteria, not the core itself.)

Does having a core buildup placed require a local anesthetic?

Yes, using a local dental anesthetic is usually needed Here’s why. to keep you comfortable.

 

 

B) What is a “post and core”?

A post & core, just like a core buildup, provides a way for a dentist to replace missing or compromised tooth structure so the shape of the tooth can be idealized as a foundation for the crown being made for it. However, this kind of restoration also includes the placement of a post inside the tooth that helps to anchor the core in place.

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

The post is cemented in the tooth’s root. Its attached core extends up inside the tooth’s crown.

While a dental core can be created for any tooth, a “post and core” can only be placed for a tooth that has already had root canal treatment. What’s this? That’s because the post (a small rod) is cemented inside one of the tooth’s root canals (the space previously occupied by tooth nerve tissue). (See picture below.)

When is a dental post 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, it’s generally considered that enough tooth structure still exists that a core by itself will suffice.

 

Enough of this tooth’s crown portion remained following its root canal procedure that no post was required.

FYI: Posts don’t strengthen teeth.

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

On the contrary, dental research has since shown that posts provide no reinforcement benefit and in fact, can actually weaken teeth and therefore place them at increased risk for fracture. (Raedel)

Research.

Heydecke – This study determined that case failures where a post had not been placed were more likely to be “repairable.” (Meaning that procedures could be performed where the damaged tooth could still be salvaged.)

Failures involving a post were more likely to result in tooth extraction due to the damage involved (such as root fracture).

Willershausen – This study evaluated 775 endodontically treated (root canalled) teeth, some of which had been restored with a post and core.

• 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, the subgroup composed of just those teeth having metal posts had a complication rate of 13.2% (twice as high).

 

The findings above 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 and provides no role in strengthening a tooth.

If enough natural tooth structure still exists (per the rules mentioned above), then no post is needed and for good reason, one should not be placed.

▲ Section references – Raedel, Heydecke, Willershausen

What are dental posts made out of?

Posts are fabricated out of a variety of materials. This includes metals such as stainless steel, titanium, or dental alloy. Other materials include zirconia (a ceramic-like material), engineered dental ceramic, glass fiber, or carbon fiber.

A post may be custom-made for the patient’s tooth by a dental laboratory. Or your dentist may select a prefabricated, standard-sized post and customize it before using it with your tooth.

How are post and cores placed?

• If the post is a separate object from the core (like when a prefabricated post is used), the post is cemented inside the tooth’s root canal space first and then the core is built up around it (not terribly unlike when a filling is placed).
• If both parts have been fabricated as a single unit (like a cast or milled post and core), then it is cemented into place.

 

FYI: We cover the topics of post construction and placement in greater detail on our Post and Core Procedure page. Jump

Additional FAQ about post & cores.

Fees for core buildups and post & cores.

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

Note: This fee is in addition to the cost of the final dental restoration (e.g. dental crown, dental bridge abutment) that will ultimately be placed on the tooth. It is also in addition to any endodontic procedure (root canal) that has been performed if that has been needed.

How much does a core buildup cost?

• Core (only).
          $245.00 – $395.00

How much does a post and core cost?

• Prefabricated post and core.
          $272.00 – $480.00

  (A prefabricated post and core is the type whose placement we describe on this page. The steps.)

• Cast post and core.
          $328.00 – $550.00

  (A cast post and core is a one-piece unit that is custom-made in a dental laboratory and then 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 we show.

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. Defined. As such, benefits typically run on the order of 50% of the procedure’s UCR fee. How this is calculated. To receive maximum benefits, the policyholder 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 Examples. 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 the 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

Longevity.

a) How long do core buildups last?

As compared to a post and core, dental core placement alone is a comparatively less involved procedure. And as such, one might expect that core-(only)-with-crown combinations typically have a high survival rate. Unfortunately, we could not find a contemporary (recent) source to quote that had investigated this issue.

Based on studies performed in the 1950s and ’60s, Shillingburg (reference link above) states that cores have been found to deliver successful service for severely damaged teeth restored with cast restorations (i.e. dental crowns) for periods of nearly 50 years.

b) How long do post and cores last?

There have been a number of studies that have evaluated different aspects related to the survival of teeth having post and cores. Generally, they seem to report a mid to long-term survival rate of around 80%.

• Two studies (Jung, Gomez-Polo) evaluated the success of teeth from a standpoint of the type of post used (prefabricated vs. cast How they’re different.).

  It was determined that both types generally offered the same expected rate of success – Jung: 90% vs. 94% at 8.5 years. Gomez-Polo: 83% vs. 85% at 10 years. (Cast vs. prefabricated posts respectively.)

• A study by De Backer evaluated teeth whose restoration included a post and core (and hence had had root canal treatment) vs. vital teeth (teeth that have a live nerve and therefore no post). It determined that the long-term survival rates (16 to 20 years) for both were similar: 75% vital vs. 79% RCT.

▲ Section references – Gomez-Polo, Jung, De Backer

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 (often due to complications associated with root fracture).

One study (Raedel), concluded that on average teeth restored with cast post and cores survived for 13.5 years (from post insertion to tooth extraction).

It was specifically discussed in the paper that this span seemed short. Their explanation was that they felt that cast post and cores (as opposed to prefabricated ones) were typically placed in the most severely damaged teeth, thus explaining the group’s low survival rate.

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

The findings above suggest that when determining the prudence of saving an existing tooth (via performing root canal treatment and then rebuilding it with a post and core and crown) versus 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. And 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 Pros / Cons) may make the wiser choice than trying to salvage your existing tooth.

▲ Section references – Raedel

Additional FAQ about treatment success.

Related pages about restoring root canalled teeth.

• The post and core placement procedure. The steps.
• Final restorations – When is a crown required after root canal treatment? The factors that decide.
• Can the tooth’s original crown just be reused? Considerations.
• This topic’s full menu. Go

Comments.

This section contains comments submitted in previous years. Many have been edited so to limit their scope to subjects discussed on this page.