Combined Periodontic-Endodontic Lesions

Combined periodontic-endodontic lesions are abscessed areas that arise from one or both of two possible locations. These lesions themselves are localized bacterial infections that arise from either the dental pulp inside the teeth, from the tissues of the periodontium that surround the tooth, or from both areas concurrently. They may also result from a fractured tooth. Combined periodontic-endodontic lesions are further subclassified based on the location of origin of the

Endo-perio lesions occur when infection that occurs within the pulp inside a tooth spreads to the bone that surrounds the very tip of the tooth’s root. In most cases of endo-perio lesions, the pulp inside the tooth is fully necrotic. The tip of the tooth root is called the apex; the infection that leads to abscess around the tip of the tooth’s root is called a periapical, or “around the apex,” abscess. The infection may spread toward the crown of the tooth and into the alveolar bone and the oral cavity by progressing along the periodontal ligament.

Perio-endo lesions arise from infection that initiates in a periodontal pocket. These are usually excessively wide periodontal pockets. This infection spreads through the accessory canals and into the root canal, which causes the pulp in the root canal to become inflamed. Periodontal disease must successfully reach the apex of the affected tooth in order for an endodontic lesion to form, as the accessory canals may not be wide enough to allow bacteria to thoroughly penetrate into the apex.

Combined periodontic-endodontic lesions are diagnosed and treated in similar ways, regardless of the source of infection. Treatment involves a combination of endodontic therapy and periodontal therapy, with endodontic therapy preceding periodontal therapy. Endodontic therapy, also known as root canal therapy, involves the removal of infected pulp from inside the root canal of the infected tooth, followed by the disinfection and decontamination of the hollowed root canal and the subsequent filling of the root with antiseptic filling materials. This eliminates infection while also protecting the tooth from future infection. Control of infection inside the tooth is necessary for subsequent periodontal therapy to be effective. Periodontal therapy focuses on mechanical removal of the plaque and tartar that lead to periodontitis, with a focus on reducing inflammation of the tissues of the periodontium. The procedure of dental scaling and root planing involves deeply cleaning the plaque and tartar from below the gumline and then smoothing the surface of the tooth’s root to discourage further bacterial accumulation. Once the teeth have been deep cleaned, further disinfection may be necessary. Dentists may use a chlorhexidine gluconate solution or site-specific antibiotics to further heal the tissues of the periodontium and encourage their healthy reattachment to the newly repaired tooth. The efficacy of periodontal treatment will be reevaluated after three to six months. Local anesthesia is used for both endodontic therapy and periodontal therapy and treatment requires multiple office visits to complete. In some cases, it is determined that damage is too severe for the lesion to be effectively treated; in these cases, the tooth cannot be preserved and must be extracted.