Combined Periodontic-Endodontic Lesions

Combined periodontic-endodontic lesions are areas of bacterial infection that are caused by infection in the dental pulp, the tissues surrounding the teeth, or a combination of both of these. These lesions appear as abscesses and are classified based on the location, or locations, of their origins. This classification is used to determine the best course of treatment and management.

An endo-perio lesion is caused by infection from within the tooth that spreads to the bone at the tip of the tooth’s root, causing a periapical abscess; this term explains that the infection originates inside the tooth, using the Greek prefix for “within” -- “endo.” The infection may then move toward the crown of the tooth, spreading into the bone and the oral cavity through the periodontal ligament. Because it originates inside the tooth and then moves into the periodontal tissue, it is called an endo-perio lesion.

A perio-endo lesion is caused by infection that originates in a periodontal pocket and proliferates into the root canal of the tooth it is adjacent to, causing the pulp inside the tooth to become inflamed. If the accessory canals that allow infection to spread into the inside of the tooth aren’t large enough to allow infection in, the disease may enter the root of the tooth through its apex. As this lesion originates with the periodontal tissue and then moves into the tissue within the tooth, it is named in that same order.

While the source of infection is helpful in determining the importance of the varying elements of treatment, and is integral to determining the best methods of management, both of these primary types of combined lesions can expect to have a similar prognosis. When a fractured tooth has caused a combined lesion to form, treatment will require repair or removal of the tooth. In all cases, if the lesion is significant enough and is determined to be too severe to respond well to treatment, the tooth may need to be removed. Treatment usually includes endodontic therapy, followed by periodontal therapy.

Endodontic therapy, also known as root canal therapy, is a treatment sequence that aims to eliminate infection within a tooth and also to prevent future infection. The root canal itself is the chamber inside the root of a tooth that is full of dental pulp, which is made up of nerve tissue, blood vessels, and other cellular material. When this pulp becomes infected, it is removed from within the tooth, and the inside of the tooth is disinfected, reshaped, and otherwise prepared for a healthy future. Periodontal therapy is sometimes referred to as a dental deep cleaning, and it is a clinical procedure in which a dentist mechanically removes dental plaque and tartar from the surfaces of the teeth, both above and below the gumline, and then smoothes the surfaces of the teeth to discourage the accumulation of further bacteria. To preserve the health of the mouth, these therapies may also include instruction on more effective home hygiene techniques and habits, as well as behavior modification therapies when necessary. Combined with periodic maintenance visits, these therapies can help prevent future lesions and the pain and discomfort they bring.