endo-periodontal lesions

Endo-periodontal lesions:

1. Definition :

 Endo-periodontal lesions include all cases where pulp pathology and periodontal pathology are related through hard tissues.

2. Reminders:

• Tooth and periodontium constitute the dental organ, a true anatomophysiological unit.
• A depulpated tooth is maintained in the arch by a healthy periodontium while a tooth with vital pulp but pathological periodontium is removed from the arch because “it is the integrity of the supporting structures and not the pulp vitality that determines the maintenance of the tooth in the arch” (according to Blair 1972).
• There is a connective and vascular continuity between the endodontium and the periodontium; if the periapical region is the privileged place of communication between the pulp and the periodontium, the role of the accessory root canals in the pulpo-periodontal exchanges should not be neglected. (Deus classification)
• fig: calssification of Deus: 

    A. main canal, B. lateral canal, C. secondary canal, D. accessory canal

endo-periodontal lesions

3. Classification of endo-periodontal lesions:

Bender and Seltzer classify these lesions into 05 categories: 

• Class I: primary endodontic lesions.
• Class II: primary periodontal lesions.
• Class III: primary endodontic lesions, with secondary periodontal involvement.
• Class IV: primary periodontal lesions, with secondary endodontic involvement.
• Class V: true mixed lesions; primary lesions meeting each other.

endo-periodontal lesions

Fig: endo-periodontal interrelations.

4. Definition of combined endo-periodontal lesion (true mixed):

For Harrington, there is a mixed endo-periodontal lesion if the tooth in question is necrotic and presents a loss of attachment and a bony defect extending from the sulcus to the apex of the tooth or to the exteriorization of a lateral canal on the root surface.

            fig: mixed endo-paro lesion. 

5. Influence and repercussions of periodontal pathology on the pulp:

Periodontal diseases cause two types of reactions in the pulp  : inflammation and degeneration.

endo-periodontal lesions

• Degenerative lesions:

• Are caused by reduced blood supply, resulting from pressure on the vessels irrigating the pulp; occlusal trauma and too rapid orthodontic movements are the most common causes.
• The pulp is supplied by several vessels and the obliteration of just one can cause a lack of blood supply in a specific region of the pulp. The greater the number of vessels obliterated, the greater the risk of pulp degeneration.
• Deep periodontal lesions expose accessory canals and interfere with circulation leading to degenerative changes.
• Inflammatory lesions:
  • Gingivitis: The early inflammatory stages of the periodontium related to plaque have no influence on the state of the pulp. As long as the cementum remains intact, the inflammation does not cross this barrier.
  • Periodontitis: In periodontitis, the granulation tissue of the diseased periodontium is in contact with the cementum. In deep lesions, signs of pulp inflammation are present (retro pulpitis).
    • Transmission modes: two transmission modes are possible:
      • Either by the  dentinal tubules exposed during intervention (curettage) or during pulp necrosis.
      • Either through the exposed accessory canals allowing communication between the pulp and the oral environment. 

6. Influence of periodontal therapies on the pulp:

• Root planing exposes the dentinal tubules and lateral canals filled by cementum; 
•  for Hatteler and Lisgarten Root planing results in the formation of a layer of reaction dentin which increases during the first 3 months, stabilizes and protects the pulp.
• Kitching et al in 1984: noted pulp modifications such as displacement of odontoblasts, pulp hyperemia and inflammatory infiltrate during ultrasonic surfacing.

7. Influence and repercussions of pulp pathology on the periodontium:

The pulp does not provide a vascular support element for the periodontium. The circulation at the apex and accessory canals in the pulp-periodontium direction is venous circulation.

Pulp diseases can only cause inflammatory lesions.

• Pulp degeneration :  Pulp degeneration does not affect the periodontium.
• Pulpitis:
  •  The venous and lymphatic pulp system transports the products of cellular catabolism to the periodontium.
  • The amount of irritants is insufficient to induce significant destruction of periodontal tissues; but it does cause desmodontal widening and interruption of continuity of the lamina dura.
  • Pulpitis usually has a moderate impact on the periodontium.  
• Pulp necrosis: necrotic pulp tissue promotes the growth of microorganisms, through the canals (main and secondary) bacterial products and those of pulp catabolism induce an inflammatory reaction of the periodontium with destruction of the fibers of the desmodont, resorption of the alveolar bone adjacent to the foramina and sometimes rhizalysis. The evolution of the periodontal lesion depends on the virulence of the germs in the root canal and the host’s defenses.
  • Chronic evolution:
    • Granuloma:
    • Cyst: 
  • Acute evolution:
    • Suppurative apical periodontitis
    • Acute apical abscess.

8. Influence of endodontic therapies on the periodontium:

Pulpectomy and root canal filling cause a periapical inflammatory reaction followed by apical repair. Only the use of toxic root canal products or iatrogenic maneuvers cause periodontal pathology, for example:

• Crossing the apex by endodontic instrumentation,
• Overflowing gutta cones,
• Insufficient root canal sealing;
•  Bacteria can proliferate in the hiatus created by a fracture or insufficient canal sealing and rapidly generate an inflammatory response of the periodontium and alveolar bone.

9. Diagnosis:
   1. Etiological diagnosis  : this will allow us to specify the pulpal or periodontal origin of the lesions and to apply etiopathogenic therapy.

• Pain: The presence of pain usually indicates endodontic involvement , especially if the pain is severe. Pain is usually absent if the periodontal disease is chronic.
• Pulp vitality  : in the presence of a periapical or lateral lesion, pulp vitality remains the determining element for the diagnosis.

Cold test, hot test, electrical test, cavity test; if the pulp is alive, the pathology is periodontal. If the pulp no longer responds to vitality tests, the lesion is endodontic. 

•  Edema  : in the event of pulp lesion, it appears in the vestibular groove, and is more coronal in the presence of periodontal lesion.

In periodontal pathology, it is rare to observe facial edema closing the eye or affecting other parts of the face.

• Periodontal probing: a narrow fistula (1 to 2 mm) descending to the accessory canal is of endodontic origin. A wider periodontal pocket allows the insertion of several probes. A mixed lesion will be revealed by a concave probing (periodontal lesion) with a punctate depression

(Endodontic lesion).

• Radiography: Bone loss of endodontic origin is limited apically to a larger surface, whereas bone loss of periodontal origin involving several surfaces is larger coronally.

10. Therapy of pulpo-periodontal lesions:

• In the case of primary endodontic lesions, with secondary periodontal involvement , the first phase of treatment will focus on root canal treatment .

The second phase will concern periodontal lesions revealed by all the elements of a serious diagnosis. 

fig: primary endodontic lesions, with secondary periodontal involvement.

• In the case of primary periodontal lesions, with endodontic  involvement ; endodontic treatment will be initial. (The severity of the inflammatory phenomena: acute pain),

Primary periodontal lesions: periodontal treatment will therefore be causal, initially.

fig: primary periodontal lesions, with endodontic involvement.

• In the case of true mixed lesions  : the healing of these mixed lesions first involves a clinical healing externalized by certain signs, the true healing remaining the regeneration of all the histological elements of the region, which will confirm the X-ray. There, doubt no longer exists. Any infectious and therefore inflammatory source is dried up.

Periodontal treatment, favorably influenced by this context, must go hand in hand with conservative endodontic therapy. 

endo-periodontal lesions