Endodontic lesions
The odontium and the periodontium are closely linked and communicate with each other via communication pathways and the alteration of one of the two can secondarily affect the other giving rise to endo-periodontal lesions.
2-Endo-periodontal communication pathways
- The main canal from the apical foramen,
- secondary channel,
- accessory canal,
- lateral canal,
- the interradicular space: area particularly rich in lateral canals,
- dentin tubules,
- iatrogenic root and interradicular perforations.
3- Classifications of Simon, Glick and Frank in 1972 of endo-periodontal lesions.
- Class I : Pure endodontic lesions.
- Class II : Primary endodontic lesions with secondary periodontal involvement.
- Class III : Pure periodontal lesions.
- Class IV : Primary periodontal lesions with secondary endodontic complications.
- Class V : Associated lesions (non-interfering in their topography).
- Class VI : Combined lesions known as true endo-periodontal lesions.
New AAP classification 2018
| Endodontic lesions with damage to root integrity | Root fracture or crack, Perforation, External root resorption |
|---|---|
| Endodontic lesions without damage to root integrity | Grade 1: Narrow, deep periodontal pocket on a tooth surface |
| Grade 2: Wide and deep periodontal pocket on a tooth surface | |
| Grade 3: Deep periodontal pocket on more than one tooth surface |
4-Etiologies of pulpo-periodontal lesions:
- Bacterial, chemical or mechanical.
- Root resorption, cracks and fractures.
There are also specific contributing factors to interradicular spaces:
- Enamel beads,
- Enamel projections.
5-Pathogenesis
5-1-Influence of periodontal disease on the pulp
Microorganisms in dental plaque, bacterial toxins and certain substances resulting from inflammation of the periodontium can cross the cementum barrier by infiltration and penetrate the dentin tubules to reach the pulp.
However, the pulp has a high capacity for defense against periodontal disease, as long as the blood supply to the apex is not impaired. Therefore, less frequently, severe periodontal disease can lead to the pulp becoming involved in contact with pathogenic elements of periodontal origin and lead to pulpitis and then necrosis.
5-2-Influence of periodontal treatment on the pulp
Endodontic lesions that may occur after trauma due to periodontal therapy can take two forms:
- Dentin hypersensitivity after root planing.
- The exposure of lateral and/or accessory canals during pocket treatment on vital teeth, the inflammatory reaction is the rule but most often reversible with the formation of reactive dentin.
- Root amputation in the case of periodontal treatment requiring separation of the roots, endodontic treatment of the root to be preserved must be carried out before the surgical procedure.
5-3-Influence of pulp pathology on the periodontium
- Pulpitis : An inflammatory lesion caused by caries, trauma, or chemical irritation. In this situation, vitality tests are exacerbated and there is no radiological image. Periodontal probing is normal.
- Pulp necrosis, acute and chronic apical periodontitis : In these situations, there is the presence of intracanal bacteria that migrate to the apical level and create periapical pathology (acute or chronic). Sensitivity tests are negative. In the acute phase, percussion is painful and a clear radiograph may be visible at the apex. Periodontal probing is normal. In these situations, therapy is strictly endodontic.
- Acute abscessed apical periodontitis : in this situation, the pulp is necrotic and infected (or the endodontic treatment is contaminated), the infection reaches the periapex and drains through the sulcus following a path of least resistance called a “fistula” which may be a true desmodontal fistula, or lifting the soft tissues and the periosteum. This warning sign may suggest a periodontal abscess, in which case it is a pulp pathology with a periodontal expression.
5-4-Influence of endodontic therapies on the periodontium
a-Mechanics and technical faults
- Root perforation, at the level of the canal walls.
- Perforation at the floor level of multi-rooted teeth.
- Root fracture.
- Mechanical accidents of anesthesia.
- Instrument fractures.
- Apical overshoots.
- Insufficient canal sealing leaving unobstructed lateral canals with their infectious contents.
b. Drug complications:
By improper handling of substances:
- Anesthetics.
- Escarotic.
- Endocanal antiseptics.
5-5-Combined endo-periodontal lesions
A single tooth may present a lesion of endodontic origin at the apical foramen or at the opening of a lateral and/or accessory canal, and at the same time, a periodontal lesion migrating apically. These two lesions, of independent origin, can communicate and even merge to form a “true endo-periodontal lesion” (Simon et al. 1972).
6-DIAGNOSTIC OF ENDO-PERIODONTAL LESIONS
For a lesion to be classified as endo-periodontal, two criteria are necessary:
- The tooth involved, at the level of the lesion, must have a negative vitality test.
- The periodontal attachment system must be broken.
a- PERIODONTAL LESIONS WITH ENDODONTIC INTERFERENCES
They are characterized by:
- A vitality test may be positive in the case of pulpitis stage and negative in the case of necrosis.
- A loss of hermeticity of the periodontal attachment system.
- Bone lysis dependent on the degree of progression of periodontitis.
- The typical morphology of a periodontal lesion is concave, with the probing ratio describing a gradually descending and then ascending curve (U-shaped circumferential probing).
- Pain, unlike periodontal disease, is the most common symptom of pulp disease. Most often, the endodontic lesion is only revealed radiographically when the invasion of periodontal tissue is effective (granulomas, cysts, etc.).
b- ENDODONTIC LESIONS WITH PERIODONTAL INTERFERENCES
They are characterized by:
- A negative vitality test.
- A loss of hermeticity of the periodontal attachment system.
- Apical or juxta-radicular bone lysis.
- Apart from pain present on pressure, the actual pulp pain, which preceded necrosis, belongs to the past in the history of the disease.
The clinical examination
It can reveal two possible manifestations of the pathology:
- Either a swelling with or without exteriorization.
- Either a desmodontal fistula with or without swelling of the marginal gingiva.
The probe will, however, be punctual, narrow (sometimes difficult), which will objectify an endodontic lesion with periodontal expression. A gutta percha cone can be placed in the attachment loss in order to objectify the causative tooth. In primary endodontic lesions with periodontal interference, the radiograph will objectify an angular lesion.
c-COMBINED ENDO-PERIODONTAL LESIONS
They are characterized by:
- A loss of pulp vitality.
- A loss of hermeticity of the periodontal attachment system.
- Marginal and apical bone lysis.
- Radiolucency in the form of two cones opposite at their apexes.
- Harrington’s V-shaped circumferential survey.
In this type of lesion, the primary pathology is difficult to identify.
7- THERAPIES AND REPAIR POTENTIAL
- Clinical experience shows that the chances of healing endodontic lesions are better than those of periodontal lesions.
- Periodontal lesions are characterized by the formation of a pocket corresponding to an apical migration of the epithelial attachment. Their progression is slow and may be accompanied by bone destruction, which is generally irreversible.
- The potential for repair of periodontal bone defects after periodontal therapy is directly related to their morphology. Only those with three or four walls can be filled.
- In endodontics, canal disinfection is possible. Endodontic lesions can therefore heal, especially since they have a circumscribed anatomy, facilitating bone regeneration.
- When a periodontal lesion is the cause of secondary endodontic damage, endodontic treatment allows for the repair of lesions occurring around the apex or at the opening of a lateral and/or accessory canal. However, no study has yet shown that endodontic treatment can contribute to the healing of periodontal disease.
- When an endodontic lesion causes secondary periodontal damage, the resulting loss of attachment is called a fistula. Disinfection of the canal by endodontic treatment allows rapid closure of this fistula without periodontal treatment.
- If it is an old lesion, even of endodontic origin, there may be infiltration of bacterial plaque inside a desmodontal fistula and apical migration of a junctional epithelium with the appearance of an angular lesion. To achieve healing of the endo-periodontal lesion thus formed, the association of periodontal treatment with endodontic treatment is necessary.
- For perforations, resorptions and fractures; endodontic treatment or retreatment will then be necessary. If there is no healing, an exploration flap may be performed to confirm the diagnosis and propose treatment.
- The chances of healing true endo-periodontal lesions are very uncertain. We can cautiously assume that the area of the lesion of endodontic origin heals after endodontic treatment, but that only periodontal treatment, the outcome of which is much more uncertain, allows healing of the area of periodontal origin.
Treatment requires endodontic treatment initially followed by periodontal treatment, as it has been shown that:
- Endocanal infection promotes apical migration of the junctional epithelium along the denuded dentin surface.
- The presence of bacteria in the canal affects the outcome of periodontal treatment.
IN SUMMARY
| Tests | Heightened/negative vitality | Survey |
|---|---|---|
| One-time survey | Vitality – | Survey + |
| Periodontal pocket at the apex | Vitality + | Survey + |
| Periodontal pocket |
| Diagnostics | Endodontic pathology | Endodontic pathology: infection, perforation, resorption, fracture |
|---|---|---|
| Endo-periodontal lesion | Periodontal pathology | Periodontal pathology |
| Treatments | Endodontic treatment | Endodontic treatment and if persistence: exploration flap |
|---|---|---|
| Endodontic treatment | Periodontal treatment at 2-3 months | Periodontal treatment |
| Pulp vitality monitoring | Periodontal treatment |
Clinical cases
9 CONCLUSIONS
Pulp vitality and loss of desmodontal attachment remain the essential elements of the differential diagnosis between the pulpal origin and the periodontal origin of the lesion, although they always require additional information.
Knowledge of the potential for periodontal and periapical repair allows for a better assessment of the therapeutic approach to be taken and the chances of success.
If endodontic involvement is evident in an endoperiodontal lesion, root canal treatment should be undertaken before any periodontal surgery, in conjunction with the initial treatment.
Endodontic lesions
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Bleeding gums when brushing may indicate gingivitis.
Short orthodontic treatments quickly correct minor misalignments.
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Interdental brushes are essential for cleaning narrow spaces.
A vitamin-rich diet strengthens teeth and gums.