A dental post is a small rod placed inside the root canal of a tooth that has already had a root canal treatment. Its job is to help support a crown when too much of the original tooth structure has been lost to hold one on its own. The post sits inside the root, a core buildup is shaped around it, and then a crown goes on top.
This is different from a dental implant, which replaces an entire missing tooth by screwing into the jawbone. A dental post works with a tooth you still have, specifically one that’s been weakened but whose root is still intact and anchored in bone.
How a Dental Post Works
After a root canal, the inside of your tooth is hollow. If the walls of the tooth above the gumline are mostly gone, whether from decay, fracture, or a large old filling, there isn’t enough structure left for a crown to grip onto. A post bridges that gap. Your dentist cements or bonds a thin rod down into one of the cleaned-out root canals, then builds up a core of filling material around the portion that sticks out above the root. That core becomes the new “stump” the crown sits on.
For years, dentists described the post’s main purpose as simply holding that core in place. But research published in The Journal of Advanced Prosthodontics paints a more nuanced picture. The amount of natural tooth structure remaining above the gumline matters far more for holding the core than the post itself does. What the post actually does best is reinforce the whole assembly against fracture. During chewing, forces concentrate at the junction where the crown meets the root. A post increases the number of chewing cycles the tooth can withstand before that critical zone cracks and the crown separates from the root. In other words, the post’s real value is structural reinforcement, not just acting as an anchor for filling material.
When a Post Is Needed
Not every root canal tooth needs a post. If a good amount of healthy tooth remains above the gumline, a crown can often be placed directly over the tooth with just a simple core buildup. Posts come into play when the tooth is severely broken down and there isn’t enough wall structure to support the crown on its own.
A few situations where a post is commonly used:
- Front teeth after root canal: These teeth are narrower and often lose a significant portion of their structure, making a post helpful for retaining the core and resisting biting forces.
- Teeth serving as anchors for bridges: When a root canal tooth will support a multi-tooth bridge, it faces higher loads, and a post can reduce fracture risk.
- Heavily restored teeth: If most of the crown was already filling material before the root canal, little natural tooth remains to work with.
Types of Dental Posts
Posts fall into two broad categories: prefabricated and custom cast.
Prefabricated posts are factory-made rods that come in standard sizes. Your dentist selects one that fits the canal, cements it in, and builds up the core around it, all in a single appointment. These are the most common type used today. They’re made from either metal (stainless steel or titanium) or fiber-reinforced composite (usually glass fiber or quartz fiber). Fiber posts have become increasingly popular because they flex in a way that’s closer to natural tooth structure. When a metal post fails under extreme force, it tends to crack the root itself, which usually means losing the tooth. A fiber post is more likely to break or debond before the root fractures, leaving the door open for repair.
Custom cast posts are made from a mold of the canal and fabricated in a dental lab, typically from a gold alloy. They fit the canal precisely, which can be an advantage in teeth with unusual canal shapes. They require two appointments: one to take the impression and one to cement the finished post. They’re less common now but still used in specific situations.
Retrospective studies have found no statistically significant difference in survival between different post materials, suggesting that the choice often comes down to the specific clinical situation and the amount of remaining tooth structure rather than the material alone.
The Placement Process
Post placement happens after your root canal is complete and the tooth has healed. Your dentist removes some of the filling material from inside the canal to create space for the post, while leaving enough sealed material at the tip of the root to maintain the infection barrier. The post is then cemented or bonded into the canal, and a core is built up around it using a composite or similar material. Finally, the tooth is prepared and crowned.
The whole process, from post placement to final crown, typically takes two to three appointments spread over a few weeks, depending on whether you receive a same-day crown or one made by a lab.
Risks and Limitations
The most serious risk associated with dental posts is vertical root fracture. This type of crack runs lengthwise down the root and almost always means the tooth has to be extracted. Among teeth that have had root canal treatment, vertical root fractures occur at a rate of about 13.4%. The presence or absence of a post is one of the strongest predictors of whether this happens, along with age, thin remaining root walls, and the time gap between the root canal and crown placement.
Perforation is another concern. Drilling space for the post can accidentally punch through the side of the root, especially in roots that curve sharply or have thin walls. Certain roots carry particularly high perforation risk: the front root of upper molars (because of its curvature) and the front roots of lower molars. Placing posts in these roots is generally avoided. Placing a post in a tooth that still has a fully intact crown is considered unnecessary and harmful, since there’s already plenty of structure to support a restoration.
Posts can also compromise the seal left by the root canal treatment. If a side branch of the canal was successfully sealed during the root canal, preparing space for a post risks breaking that seal and reintroducing a pathway for bacteria.
Long-Term Survival
Studies tracking teeth restored with posts over a decade report 10-year survival rates ranging from about 59% to 83%. That’s a wide range, and outcomes depend heavily on how much natural tooth was left, the quality of the root canal, and the forces the tooth faces during chewing. Teeth with more remaining wall structure consistently perform better than those relying mainly on the post for support.
When a post-and-core restoration does fail, the outcome depends on the failure mode. A debonded or broken fiber post can sometimes be removed and replaced. A root fracture, on the other hand, typically ends with extraction and a decision about replacement options like an implant or bridge.
Cost of a Dental Post and Core
In the United States, a post and core procedure typically costs between $250 and $650. This is separate from the cost of the crown that goes on top, which adds another several hundred to over a thousand dollars depending on the material. Dental insurance often covers post and core as part of a major restorative benefit, though coverage percentages vary. The total investment for a root canal, post, core, and crown on a single tooth can run from roughly $2,000 to $4,000 or more without insurance.
Dental Post vs. Dental Implant
These two are frequently confused because both involve a “post” placed into bone or tooth structure, but they solve completely different problems. A dental post goes inside an existing tooth’s root to help support a crown. A dental implant replaces a tooth that’s already gone. The implant is a titanium screw placed directly into the jawbone, where it fuses with the bone over several months and then receives its own crown through a connector piece called an abutment.
If your tooth can be saved with a root canal and post, that’s generally the preferred path, since keeping a natural root preserves bone and is less invasive than extraction and implant surgery. But if the root is fractured, severely infected beyond repair, or otherwise unsalvageable, an implant becomes the more reliable long-term option.