A tooth build-up, often called a core build-up, is a restorative base placed onto a damaged tooth. This procedure uses durable filling material to replace missing coronal tooth structure, the part of the tooth visible above the gum line. The build-up creates the necessary shape and bulk to successfully support a permanent dental crown. Without this foundation, a crown would lack the retention and resistance required to withstand biting and chewing forces.
When Structural Support is Required
A core build-up is necessary when a tooth has lost a significant amount of healthy structure, making it unable to support a crown. This loss often results from extensive decay or when a large, existing filling has fractured or failed, leaving the remaining tooth walls thin and weak.
Another common scenario is after a tooth has undergone root canal treatment, which requires the removal of internal tooth structure. The remaining tooth structure must have a certain height and surface area for a crown to securely grip. If the remaining structure is three millimeters or less circumferentially, a build-up is required to provide a solid, reinforced platform.
Step-by-Step Procedure
The process begins with the administration of a local anesthetic. The dentist then meticulously removes all existing decay, old filling materials, and any unsupported tooth tissue. The cleaned area is prepared with conditioning agents to promote a strong bond between the remaining natural tooth and the build-up material.
To keep the working area dry and clean, a rubber dam is placed around the tooth to achieve optimal bonding strength. A small plastic or metal band, known as a matrix, may be wrapped around the tooth to act as a mold for the core material. The restorative material is then carefully placed into the prepared space, often using a syringe to ensure complete filling.
If a light-cured composite resin is used, a high-intensity light is applied to harden the material almost instantly. Once the material is set, the matrix is removed, and the dentist sculpts and shapes the new core. This final shaping prepares the tooth with the appropriate geometric form to receive the impression for the custom-made crown.
Materials and Structural Variations
The materials used for a core build-up are chosen for their strength, durability, and ability to bond with the natural tooth. Composite resins, which are tooth-colored plastic materials, are frequently used due to their excellent adhesive properties and ability to be hardened quickly. Glass ionomer cements are another option, sometimes selected for their ability to release fluoride.
When a tooth has lost more than half of its coronal structure, especially following root canal therapy, a simple core build-up may not provide sufficient anchoring. In these cases, a “Post and Core” procedure is performed, which involves placing a dental post for internal reinforcement. The post is cemented into the root canal space, acting as a sturdy internal anchor.
The post itself does not strengthen the root, but it mechanically retains the core build-up material, much like rebar in concrete. Posts are commonly made from metal alloys or fiber-reinforced composite materials. The core build-up material is then placed around the exposed head of the post to create the final foundation.
Caring for the Restored Tooth
Following the core build-up, some patients may experience temporary sensitivity to hot or cold temperatures. If a temporary crown is placed while the permanent one is being fabricated, avoid chewing hard, sticky, or crunchy foods on that side of the mouth. These foods can dislodge the temporary restoration or the underlying build-up material.
Once the final crown is cemented, maintaining excellent oral hygiene is necessary for the restoration’s longevity. While the crown and build-up material cannot decay, the natural tooth structure at the margins remains susceptible to cavities and gum disease. Regular brushing twice a day and daily flossing around the crown’s edges prevent plaque accumulation. Patients who clench or grind their teeth at night should discuss a custom-fitted night guard with their dentist, as excessive force can damage the crown or foundation.