Definition: A root fragment of a primary tooth that has not been resorbed and remains within the jawbone after the crown has exfoliated.
Radiographic Features:
- Location:
- Most common: Mesial and/or distal to second premolar
- More frequent in mandible than maxilla
- Can occur throughout maxilla and mandible
- Edge: Well-defined, may show remnant periodontal ligament space
- Shape: Typically linear or curved
- Internal structure: Radiopaque, density similar to dentin
- Other: None specific
- Number: May be single or multiple
Key points:
- Most commonly affected tooth: Deciduous second molar
- Can persist for years without symptoms
- May interfere with eruption of permanent successor
- Difficult to differentiate from enostosis if periodontal ligament space is absent
Clinical significance:
- Usually an incidental finding
- Generally doesn’t require treatment if asymptomatic
- May cause delayed eruption of permanent teeth
- Could potentially lead to cyst formation (rare)
Note: If no periodontal ligament space is visible, differentiate from enostosis based on shape. Linear shape suggests retained root fragment. Neither typically requires treatment if asymptomatic.