Endo-Perio Lesions Classification

In order to understand this process, we start from the assumption that there are only two origins: endodontic or periodontic. The true endo-perio lesion can be produced only from independent endo and perio lesions, that merge together in a tooth. This is the reason why these types of process should be classified as follows:

• endodontic lesion
• endodontic lesion with secondary periodontal involvement
• periodontic lesion
• periodontic lesion with secondary endodontic involvement
• endo-perio lesion.

Endodontic disease

The pulp disease produces fast destruction of the attachment apparatus of only one tooth from the apex to the crown, having acute and chronic phases. The pulp test is negative, but can be still positive in a multirooted tooth.

Usually, the endodontic lesion develops as an acute process, with characteristic symptoms. The "endodontic pain" usually presents as throbbing and spontaneous pain concentrated on a tooth. In this case, the patient seeks immediate treatment and the removal of the irritant stops the inflammatory process without affecting the attachment apparatus.

Sometimes the presence of a low-grade irritant will start a chronic inflammatory process that produces only mild or no symptoms but leads to the inflammatory process spreading into the attachment apparatus. Once this is involved to the extent of producing an accumulation of inflammatory cells, the body looks for a drainage path.

The drainage can be done in several ways with three different clinical consequences. If the attachment apparatus is not affected (no probing defect), an extraosseous fistula can perforate the osseous flat area and the periosteum, exiting intraorally or extraorally. Alternatively, a subperiosteum fistula can perforate the bone plate but not the periosteum and drain through the sulcus, which visually resembles a periodontal injury, but with normal probing.

If the attachment apparatus is affected, the periodontal ligament space can be probed by "tunneling". This kind of retrograde periodontitis, due to the drainage direction from apical to cervical, can be confused with a periodontal furca lesion in a multiradicular tooth.

However, there is no permanent damage in the cement and the fibers of the periodontal ligament, so this type of lesion causes a loss of insertion that can be totally reversed by endodontic treatment. If the lesion is not treated early, especially furca injuries, a secondary periodontal infection can be produced and this will worsen the prognosis for the tooth.

The characteristics of the pulpal space allow a special symbiosis of bacteria, mainly anaerobic. In time this will result in a high concentration of Bacteroides and Bacillus Gram-positive, with extreme symbiotic relationships, and only a small number of bacteria from one or two dominant families.