A 38 year old female patient was referred in pain with a previously root filled lower left molar. On examination the tooth was extremely tender to touch and there was buccal swelling present with suppuration and exudate at the gingival margin in the furcation region. There was no evidence of vertical fracture present and radiographically the root canal treatment was sub-optimal particularly on the mesial roots.

Retreatment was carried out with copious irrigant exposure and activation with passive ultrasonics and the access cavity was restored with dual cured composite material. The patient was put on antibiotic therapy and the symptoms had markedly improved 24 hours after treatment and subsided completely within one week. Follow up radiograph shows complete resolution of the furcation bone loss and the patient was advised to have a cast restoration with her referring dentist.