Endodontically treated teeth are teeth that have been treated for problems involving the inside of the tooth, known as the tooth pulp. The tooth pulp contains the vital blood vessels, nerves, and connective tissue, which can become inflamed or infected as a result of tooth decay, injury or significant dental work.
Restoration of endodontically treated teeth
The restoration of endodontically treated teeth is one of the most widely studied and controversial subjects in dentistry.
Restoration aims to promote coronal sealing and avoid microleakage and contamination, while also replacing the lost tooth structure and protecting the remaining structure from further damage and fracture.
The restorative treatment of endodontically treated teeth varies, ranging from minor, direct restorations to complex, indirect restorations that require the placement of an intraradicular post and core.
The choice of restoration for endodontically treated teeth depends heavily on the amount of coronal tooth tissue and hard tooth structure remaining. This factor will determine whether the retention can be retained, as well as the susceptibility of the tooth to fractures. Other influencing factors include the patient’s prosthetic need.
Restoring anterior teeth
- Composite resin restoration – For teeth that only require minimal or moderate restoration. Positioning the composite below the cemento-enamel junction provides a good coronal seal while reducing the tooth’s susceptibility to fracture. This is a particularly good option for young patients, where the teeth have suffered trauma and the root canal walls are thin.
- Ceramic or composite resin veneers – Veneers usually cover the labial surface of the tooth. They are not usually recommended for endodontically treated anterior teeth as it is difficult to incorporate the access cavity, and tissue loss can mean there is minimal surface area available for bonding.
- Metal-ceramic crowns – These are commonly used for anterior endodontically treated teeth that need crowning. It’s important to note that the liable surface must be reduced by approximately 1.8 – 2mm, which can compromise the strength of the remaining tooth tissue.
- All ceramic crowns – Ceramic crowns offer a better aesthetic result, with less preparation than metal-ceramic crowns. However, the tooth preparation must be very precise so that stress isn’t concentrated under the crown, leading to micro-cracks and fractures.
Restoring posterior teeth
- Amalgam restoration – This approach offers good, long-term results, but has become less popular over recent years due to aesthetic limits. The method is non-adhesive. If used without cuspal coverage, it can lead to a higher risk of cusp or root fracture. As a result, cuspal coverage is not recommended.
- Composite resin restoration – This is not usually a suitable long-term solution for posterior teeth, as they will typically have lost large amounts of tooth structure. Composite resin is most often used to build-up a core filling, ahead of the crowning of the tooth.
- Gold onlays and crowns – Gold restorations are incredibly durable. They are best suited to posterior teeth where aesthetics isn’t a key concern, particularly upper second molars.
It is generally suggested that a post is placed in the restoration of endodontically treated teeth where there isn’t enough of the tooth remaining to support the core.
Survival of endodontically treated teeth
Endodontically treated teeth have a good survival rate.
A 2004 study of 1,462,936 teeth recalled at 8 years indicated a 97% survival rate, while 85% of the teeth that were lost had had no full coronal coverage restoration. This was supported by a more recent study, which demonstrated a four year survival rate of 95% and ageing teeth with cast restorations survived better than those without.