External Resorption

Definition: The progressive loss of tooth structure from the outer surface of a tooth root.

Radiographic Features:

  • Location: Most common at tooth apices, but can affect any portion of the root within bone
  • Edge: Well-defined, smooth outline with altered tooth shape
  • Shape: Often appears as blunted or linear apex instead of tapered
  • Internal structure: Radiolucent area over the root structure
  • Other: Pulp chamber/root canal outline remains visible when resorption overlaps these areas
  • Number: May affect single or multiple teeth

Key points:

  • Can be physiological (e.g., primary teeth) or pathological
  • Various types: surface, inflammatory, replacement, cervical
  • Often asymptomatic and discovered on routine radiographs
  • May be associated with trauma, orthodontic treatment, or idiopathic causes

Clinical significance:

  • Can lead to tooth loss if severe or progressive
  • Treatment depends on extent, location, and etiology
  • May require endodontic therapy, surgical intervention, or extraction
  • Early detection crucial for preserving tooth structure and function

Note: Differentiation from internal resorption can be challenging, especially on facial/lingual surfaces. Use shift-shot technique or CBCT for accurate diagnosis. If the radiolucent area is continuous with the pulp space, internal resorption is more likely.