Combined Periodontic-Endodontic Lesions

Periodontology is a specialized area of dentistry which focuses on the supporting structures of the teeth and the diseases/conditions which impact these structures. The periodontium or supporting tissues, includes the following: gingiva, alveolar bone, cementum, and periodontal ligament. A periodontist is a dentist who focuses on the prevention, diagnosis and treatment of periodontal diseases. Periodontists can also specialize in the placement of dental implants.

Although there has been decades of literature which attempts to define periodontal-endodontic (perio-endo) lesions, they continue to be a disease which is largely misunderstood. The anatomic connections between the dental pulp and the periodontium offer a method of perio-endo communication. Each of these tissues has a mesenchymal origin. Once mature, they remain connected through the following methods: apical foramina, lateral canals, exposed dentinal tubules, and developmental grooves. These pathways offer an opportunity for pulpal diseases to affect the periodontium. The pathways also act as an ingress for periodontal disease to impact the pulp in a negative way. Published literature regarding periodontal-endodontic lesions often varies in the type of terminology, the criteria for diagnosis, and methods used to manage the condition. These numerous variations, in addition to the clinical and radiographic commonalities between perio-endo lesions and other dentoalveolar pathoses, make for a challenging diagnosis. Combined periodontic-endodontic lesions are typically localized and restricted areas of bacterial infection which starts in the dental pulp, periodontal tissues which surround the tooth, or a combination of both.


Combined periodontic-endodontic lesions take on the form of an abscess and typically begin from one of two distinct locations:

  • Endo-Perio: occurs when the infection from the pulp of the tooth is able to spread into the bone immediately surrounding the tip, apex, or root of the tooth to form a periapical abscess. This type of infection is then able to multiply coronally and communicate with the alveolar bone and the oral cavity as it spreads throughout the periodontal ligament.
  • perio-Endo: this type of infection occurs from a periodontal pocket and can multiply through the accessory canals into the root canal of the impacted tooth. This causes a pulpal inflammation. It is possible, however, that the accessory canals may not be large enough to allow for bacterial penetration. The apex of the tooth much be reached by periodontal disease in order to induce an endodontic lesion.

The prognosis, treatment and management of the condition are not dependent on the infection source. A combined lesion can also occur as the result of a fractured tooth.


Treatment often starts with conventional endodontic therapy and is followed by a conventional periodontal therapy. If the lesion is too severe to be effectively treated, it may be necessary to remove the effected tooth. A proper diagnosis is critical for ensuring the treatment is effective and prompt.

It is common for the treatment for primary endodontic lesions to involve a non-surgical root canal therapy along with complete restorative care. In this cases, periodontal intervention is not required and the outcome is predictable. The success rate for non-surgical root canal therapy is up to 97%.

For many dental professionals, it is difficult to properly diagnose perio-endo diseases. Accurate diagnoses are made more challenging from a lack of consistent terminology used in academic literature. The use of consistent terminology for a complete and systematic approach in the diagnoses and treatment of the condition can have improved patient outcomes.