Terminology is always a difficult thing in dentistry, and endo-perio lesions can lead to some confusion. This post will look at the basics of these lesions and how to easily classify, diagnose and manage them.


These lesions can be simply classified, however the difficulty arises in the fact that endodontic and periodontal lesions can often join together – making diagnosis and differentiation quite difficult.

Types of lesions we can have include:

  • Primary endodontic lesions
  • Primary endodontic lesions with secondary periodontal involvement
  • Primary periodontal lesions
  • Primary periodontal lesions with secondary endodontic involvement
  • A true combined lesion

There is a very obvious continuum in these lesions where, for example, an endodontic infection can easily spread to the periodontium and vice versa.

A diagram that summarises lesion development the relationships between them. (Shenoy N, Shenoy A. Endo-perio lesions: Diagnosis and clinical considerations. Indian J Dent Res 2010;21:579-85)

Endodontic Origin

If we were to look at endo-perio lesions that began from the endodontic tissue, there are a number of potential causes:

  • Endodontic infection spreading through the pulp and exiting through the apex/accessory canals into the periodontal ligament
  • Iatrogenic damage during endodontic treatment, including perforations
  • Internal resorption of the roots causing infection to gradually move out

Periodontal Origin

There are two main paths that can be taken by infection if it originates in the periodontium:

  • Periodontitis leading to pulpal necrosis via canals
  • External resorption through infection

Combined Origin

These are true lesions with uncertain aetiology.


There are a number of things we can look at in order to diagnose these lesions and to differentiate the type and potentially the origin. The things we want to address when trying to come to a diagnosis include:

  1. History
  2. Pain
  3. Pulp Vitality
  4. Periodontal involvement: pockets, mobility
  5. Tender to percussion
  6. Swelling
  7. Radiographic findings


  • Do they have a history of periodontal problems? This may indicate that there is periodontal involvement
  • Have they had any recent restorations or any trauma to the tooth? If so, how deep was this insult? This may indicate endodontic involvement
  • What is the nature of the pain? A sharp, pulpitic pain may indicate endodontic involvement, progressing to a dull continuous ache with peri-apical involvement; whereas a diffuse pain may be more periodontal (although periapical┬ápain can sometimes, initially, be diffuse)

Pulp Vitality

Essentially we are looking at the endodontic state of the tooth; this can be tested using ethyl chloride or an electric pulp tester:

  • A tooth that responds as vital is likely to be periodontal in origin
  • A tooth that responds as non-vital can either be endodontic or it could be a combined lesion (where the pulp has been lost)

Pulp testing, however, is known to be quite unreliable and so you must be cautious. The colour of the tooth can also be an indication, with non-vital teeth appearing discoloured.

Periodontal Involvement

We can check mobility and pocket depths around a tooth:

  • If there is strictly pulpal involvement then there won’t be any periodontal defects (unless the patient suffers from periodontitis)
  • If there is peri-apical involvement then there is likely to be a defect at ONE site, which is unusual for the patient
  • A periodontal lesion will tend to have numerous periodontal defects

Tender to percussion

Generally, if a tooth has peri-apical involvement it will be TTP. If there is just periodontal involvement then it usually responds normally to this. The patient may also struggle to bite on the tooth as it becomes extruded.


Swelling will be present if there is peri-apical involvement of the tooth, and this is generally quite well localised. Periodontal involvement may also present with localised swelling.

Endo-Perio Lesion

Radiographic Findings

On a periapical radiograph, there are a number of things to look out for:

  • Any restorations/caries: look at the depth and the relation to the pulpal space
  • Any radiolucencies: where are they in relation to the apex of the tooth and any canals?
  • Any loss of bone: where is the bone being lost? Is it more at the crest or towards the apex?
  • Any other associated pathology or abnormalities?


Management of such lesions can be quite complex. Always consider extraction as a treatment option as the tooth is often quite heavily involved by this stage.

If the tooth is vital and is believed that there is only periodontal involvement, then a full periodontal treatment regime should be put in place. However, the chances of this being successful are slim and the pulp may well become non-vital.

If the tooth is non-vital then the endodontic treatment should be done first and then a period of several months is left before reassessing the tooth. Often periodontal treatment will also occur.

If adequate results are still not obtained then it may be a case of periodontal surgery and raising a flap. Additionally, procedures such as hemisection of the tooth or root removal may be considered to remove the source of infection.

Endo-Perio Lesions Summary

  • These lesions may be restricted to the pulp, the periodontium or be combined
  • Development is usually due to spread of infection from one environment to another
  • Diagnosis can be difficult but includes looking at the tooth vitality, radiographs and studying the history of the patient
  • Management involved treating both periodontal and endodontic aspects as necessary

References and Recommended Reading

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BDS (Hons.) MFDS RCPS (Glasg.) Cert Med Ed FHEA - Currently working as a Speciality Doctor in OMFS and as an Associate Dentist


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