A core buildup is a restorative procedure used in dentistry to reconstruct a significantly damaged tooth structure before it receives a dental crown. This process involves replacing the missing natural tooth material with a durable filling substance, creating a stable core for the tooth. The procedure is necessary when the remaining tooth is compromised and cannot adequately support the mechanical forces and retention requirements of a crown. By rebuilding the inner structure, the core buildup ensures the final prosthetic will have a strong and properly shaped base.
When a Core Buildup is Necessary
A core buildup is recommended when a tooth has suffered extensive loss of its natural structure, leaving insufficient material for successful crown placement. This structural compromise often results from significant tooth decay that necessitated the removal of large volumes of tissue. Large fractures or breaks extending into the tooth’s interior can also remove too much material to support a restoration.
The procedure is frequently performed on teeth that have had a root canal treatment, as this removes the internal pulp and leaves the tooth more brittle and hollowed out. Teeth that have repeatedly received large, old fillings may also lose too much surrounding dentin and enamel. The remaining tooth structure lacks the necessary height, surface area, and integrity to provide the long-term support required for a crown’s retention and resistance to chewing forces.
The Role of Retention Pins
Retention pins are used when the remaining tooth structure is severely limited and cannot provide adequate mechanical retention for the buildup material. These are small, threaded metal devices carefully placed into the healthy dentin of the remaining tooth. The pins act as anchors, mechanically locking the core material onto the tooth structure.
Pins do not provide structural strength to the tooth or the final restoration; their sole function is to prevent the core buildup material from dislodging before the crown is cemented. They are self-threading, screwing into a small hole drilled into the dentin to secure themselves firmly. Pins are not required for every core buildup, but they are used when adhesive bonding alone is insufficient to hold the restorative material in place against functional stresses.
The Core Buildup Procedure and Materials
The core buildup procedure begins with the dentist administering a local anesthetic. Any existing decay, old filling material, or weakened tooth structure is removed to create a clean, healthy base. If retention pins are necessary, small channels are drilled into the dentin, and the threaded pins are screwed into place.
The tooth surface is then prepared using an etching agent and a dental adhesive to maximize the bond with the core material. The primary materials used are composite resins or resin-modified glass ionomer cements. Composite resin is favored for its strength, tooth-like appearance, and ability to bond tightly to the tooth structure. The core material is applied, often using an auto-mix syringe, and sculpted to recreate the ideal shape of the tooth’s core before being hardened by a curing light.
Core Buildup as a Foundation for a Crown
The core buildup functions as an artificial dentin substitute that restores the tooth’s original form. Once the core material has hardened, the dentist shapes and prepares it, along with the remaining natural tooth, into the geometric form required to receive a dental crown. This preparation creates the necessary taper and height, known as the “crown preparation,” which is essential for the crown to fit precisely and remain stable.
The finished core buildup is covered by the permanent crown, which acts as a protective cap and provides the final chewing surface. The success and longevity of the entire restoration depend on the strength and stability of this core foundation. By creating a robust base, the core buildup ensures that the final crown will withstand the forces of biting and chewing over many years.