A male in his thirties came to the clinic with a concern that had been gradually worsening a small gum boil near a crowned tooth in the lower jaw. He reported no severe pain but mentioned occasional discomfort and a persistent bad taste, especially in the mornings. The clinical presentation pointed toward a classic case of chronic infection.

Clinical Findings

Upon examination, an intraoral sinus tract was identified adjacent to a previously root canal-treated tooth. The sinus tract was non-tender and expressed a small amount of pus upon pressure. The involved tooth had a full-coverage crown, appearing intact externally.

Radiographic Analysis

A radiograph of the tooth revealed:

  • Previous RCT, but poorly filled canals
  • A periapical radiolucency, consistent with chronic apical periodontitis
  • No visible signs of root fracture or perforation These findings confirmed the failure of the initial root canal treatment, likely due to incomplete cleaning or persistent bacterial infection in the root system.

Diagnosis

  • Previously root canal-treated tooth with crown
  • Chronic apical periodontitis evidenced by the sinus tract and periapical lesion
  • Indication for nonsurgical endodontic retreatment.

Treatment Steps

1. Crown RemovalTo access the underlying tooth structure and canals, the existing crown was carefully removed and set aside for re-evaluation and possible reuse.

2. Gutta-Percha Removal and Canal Re-entryThe old root canal filling material (gutta-percha) was completely removed. This allowed for a full inspection and re-instrumentation of the root canal system.

3. Intracanal Medicament (ICM) PlacementOnce the canals were thoroughly cleaned and shaped, calcium hydroxide was placed as an intracanal medicament. Its antibacterial properties helped eliminate residual infection and promote healing of the periapical lesion.

4. Final Canal Sealing and Core RestorationAfter verifying that the sinus tract had resolved and symptoms had subsided, the canals were permanently obturated. A strong core build-up was completed with composite to restore the internal structure of the tooth.

5. Crown ReplacementFollowing successful endodontic retreatment and restoration, the tooth was re-evaluated for crown coverage. A new crown was fabricated and placed, restoring both function and aesthetics.

Clinical Outcome

The sinus tract resolved completely after the medicament phase, and the patient reported no further discomfort. The radiograph taken at the follow-up visit showed early signs of periapical healing. The retreatment was successful, and the new crown provided a stable, protective restoration.

Key Takeaways

  • Intraoral sinus tracts are often signs of chronic infection from a failing root canal.
  • Successful retreatment requires thorough removal of the original filling, proper disinfection, and time for healing.
  • The use of calcium hydroxide as an interim dressing is essential in managing persistent infection.
  • Full coverage with a new crown protects the restored tooth and ensures long-term success.

Conclusion

This case highlights how even a crowned, previously treated tooth with a chronic lesion can be salvaged through careful retreatment. With accurate diagnosis, methodical disinfection, and proper restorative protocols, the tooth was successfully preserved and returned to optimal health and function.

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