Clinical Classification (Modified from Torabinejad and Trope 1996)

Based on the origin of the periodontal pocket:

• Endodontic Origin
• Periodontal Origin
• Combined Endo-Perio Lesions:
  • Separate endodontic & periodontal lesions
    • No communication
      • A separate periapical radiolucency and a periodontal pocket exist, but they do not connect.
  • With communincation

Problematic Terminology

Issues with “Combined Endo-Perio Lesions”[^19]

• Combined Endo-Perio Lesions:

  • Separate endodontic & periodontal lesions
    • No communication
  • Lesions communicate

• WITH communication:** The periodontal pocket probes directly to the periapical lesion.

  • ✅ Possible
  • ? Meaningful
  • ? Useful

• Endodontic Origin

• Same as the 'primary endo lesion' from the 1972 classification; it is a purely endodontic disease.

  • Not “Endo-Perio” - only Endo.

• Periodontal Origin

• Same as the 'primary perio lesion'; it is a purely periodontal disease.

  • Not “Endo-Perio” - only Perio.