Endo-Periodontal Lesions

Scope

This note covers endo-periodontal lesions (EPL) only. Periodontal abscesses and necrotizing periodontal diseases are covered in the companion note Periodontal Abscesses and Necrotizing Periodontal Diseases. Both are drawn from the same 2018 World Workshop review by Herrera et al. (see Acute periodontal lesions (periodontal abscesses and necrotizing periodontal diseases) and endo‐periodontal lesions).

What an Endo-Periodontal Lesion Is

An endo-periodontal lesion (EPL) is a pathological communication between the pulpal (endodontic) and periodontal tissues of a given tooth. It may present in an acute or chronic form, and almost invariably involves both the periodontium and the pulp–root canal complex.

The pulp and periodontium communicate via:

• Apical radicular foramina
• Accessory (lateral) canals — most prevalent in the apical third, but also common in furcation regions
• Dentinal tubules

Migration of microorganisms and inflammatory mediators through these pathways drives the lesion. Microbiologically there is no specific EPL profile — the root canal and periodontal pockets harbour similar anaerobic flora (red/orange complex species such as P. gingivalis, T. forsythia, Parvimonas micra, plus Fusobacterium, Prevotella and Treponema).

EPLs may be triggered by:

• A carious lesion that affects the pulp and secondarily the periodontium
• Periodontal destruction that secondarily affects the root canal
• Both events concomitantly (the less common “true-combined” lesion)

Classification (2018 Scheme)

The 2018 classification (Herrera et al., Table 6) abandons the older origin-based 1999/Simon schemes and instead classifies by present disease status and prognosis — specifically, presence/absence of root damage, presence/absence of periodontitis, and the extent of periodontal destruction.

Category	Sub-category	Grade / Detail	Prognosis
EPL with root damage	Root fracture or cracking	—	Generally poor to hopeless
	Root canal or pulp chamber perforation	—	Generally poor to hopeless
	External root resorption	—	Generally poor to hopeless
EPL without root damage — in periodontitis patients	Grade 1	Narrow deep periodontal pocket in 1 tooth surface	Best within group
	Grade 2	Wide deep periodontal pocket in 1 tooth surface	Intermediate
	Grade 3	Deep periodontal pockets in >1 tooth surface	Worst within group
EPL without root damage — in non-periodontitis patients	Grade 1	Narrow deep periodontal pocket in 1 tooth surface	Best overall
	Grade 2	Wide deep periodontal pocket in 1 tooth surface	Intermediate
	Grade 3	Deep periodontal pockets in >1 tooth surface	Worse

Notes on the scheme:

• Root damage = lesions associated with trauma or iatrogenic factors (perforation, fracture/cracking, external resorption, or pulp necrosis draining through the periodontium). These affect tooth structure directly and carry the worst prognosis.
• For lesions without root damage, prognosis is worse in periodontitis patients than in non-periodontitis patients, because of the altered oral ecology and difficulty restoring health in severe periodontitis with deep pockets.
• Single EPLs in non-periodontitis patients are most often associated with palatal/radicular grooves.

Diagnosis

Diagnosis proceeds in stages (history → examination → periodontal/pulpal assessment):

• History: identify trauma, endodontic instrumentation, or post preparation — these point toward root damage.
• Radiographs: assess root integrity for perforations, fractures, cracking, or external resorption. A radicular groove can mimic a vertical root fracture radiographically — examine carefully.
• Pulp vitality testing: an EPL without root damage typically shows altered/absent pulp response (the source paper found altered pulp response in ~100% of analysed EPL cases).
• Probing pattern: a deep periodontal pocket reaching or close to the apex, combined with absence of pulp vitality, indicates an EPL. Probe depth, attachment level, bleeding on probing, suppuration and mobility full-mouth.
• Percussion tests as an adjunct.

If perforations/fractures are not identified, proceed to full-mouth periodontal assessment plus vitality and percussion to confirm and grade the lesion.

Treatment & Prognosis Implications

• Endodontic treatment is the first step for EPL without root damage, followed (where needed) by periodontal therapy — both the root canal and the periodontal tissues require management, regardless of which was the primary source.
• Grade and root damage drive prognosis. Three prognostic groups:
  • Hopeless — typically EPL caused by trauma or iatrogenic factors (root damage).
  • Poor to favourable — EPL associated with endodontic and periodontal infections, depending on the extent of periodontal destruction and the severity of any periodontitis.
• Furcation involvement, high bone destruction, and anatomic problems (e.g. grooves) worsen prognosis.
• For EPL with root damage, prognosis is generally poor/hopeless — extraction is often the outcome where the root structure is compromised beyond repair.

Source

Compiled from the 2018 World Workshop review: Herrera D, Retamal-Valdes B, Alonso B, Feres M. Acute periodontal lesions (periodontal abscesses and necrotizing periodontal diseases) and endo-periodontal lesions. J Clin Periodontol. 2018;45(Suppl 20):S78–S94 — see Acute periodontal lesions (periodontal abscesses and necrotizing periodontal diseases) and endo‐periodontal lesions. Classification per Table 6 of that paper.