An endodontist can typically perform a root canal procedure through an existing dental crown. This is often the preferred strategy because it preserves a functional and aesthetically pleasing crown. An endodontist is a specialized dental practitioner focused on treating diseases and injuries of the dental pulp, the soft tissue inside the tooth. Performing the procedure through the crown saves the patient the time, cost, and effort associated with removing and replacing a crown that is otherwise in good condition.
Creating the Access Point
The procedure begins with the creation of a small opening on the chewing surface of the existing crown. This access opening must be sized to provide space for instruments to reach the pulp chamber while maintaining the structural integrity of the crown. Endodontists use specialized, high-speed rotary instruments, such as diamond or carbide burs, to penetrate the crown material.
The crown material dictates the specific drilling technique and the type of bur selected. Porcelain or PFM crowns require a gentle, water-cooled approach to prevent the ceramic layer from fracturing. Accessing a full metal crown involves using specific carbide burs designed for efficient removal of the alloy.
Once the access is made, the endodontist navigates through the underlying filling material and tooth structure to locate the pulp chamber. Precision is required to ensure the access path aligns correctly with the root canal system. Correct alignment prevents accidental perforation into the tooth’s root or surrounding bone.
The opening provides the pathway for the subsequent stages of root canal therapy. Specialized files and irrigation solutions are used to shape and clean the canal system. After removing the infected pulp tissue, the canals are sealed and filled with gutta-percha to prevent future contamination.
Post-Treatment Sealing and Restoration
Following root canal therapy, the access opening must be sealed to protect the treated canal system. Sealing prevents bacteria and oral fluids from re-entering the tooth, which could lead to procedure failure. The endodontist typically places a temporary filling material into the access cavity before the patient is released.
This temporary seal often consists of materials like a flowable composite resin or glass ionomer cement. For the final, permanent restoration, the patient is referred back to their general dentist within a few weeks. The general dentist removes the temporary material and places a stronger, more durable filling to ensure the crown’s long-term function and aesthetic appeal.
The choice of permanent filling material, such as composite resin or amalgam, depends on the size of the access hole and the existing crown material. The goal is to ensure the new restoration matches the strength and surface contour of the surrounding crown structure. This maintains proper occlusion and prevents future wear or failure of the crown.
Reasons for Crown Removal
While drilling through a crown is the standard approach, specific clinical circumstances may require the entire crown to be removed before the root canal procedure can begin. A primary reason for recommending removal is the detection of underlying structural issues that cannot be adequately addressed through a small access hole.
Structural Compromise
If the existing crown shows clear evidence of leakage, or if secondary decay has developed beneath the crown margins, the restoration must be taken off. Leaving decay in place or failing to fully seal a leaking margin compromises the long-term prognosis of both the tooth and the new root canal treatment. Addressing these issues requires complete access to the underlying tooth structure.
Anatomical Challenges
The anatomy of the tooth and the alignment of the root canals can also necessitate crown removal. If the tooth is positioned at a severe angle, or if the ideal access path would require drilling an extremely angled or non-straight line, removing the crown provides the best chance for a successful procedure. A straight-line access is preferred to minimize the risk of procedural errors, such as canal transportation or root perforation.
Crown Material and Quality
The material and quality of the crown are additional factors in the decision-making process. Some highly aesthetic, all-ceramic crowns have a heightened risk of experiencing catastrophic fracture when a high-speed drill is used on their surface. Dentists may advise removal in these cases to prevent irreparable damage to an expensive restoration. Furthermore, if the crown is already near the end of its expected lifespan or is poorly fitted, the dentist may recommend replacing it with a new crown after the root canal is completed to ensure the best possible long-term functional outcome.