Should this tooth be retreated or extracted?

Patient: 76 year old female with controlled hypertension and arthritis

Chief Complaint: History of pain and swelling of one week duration (maxillary right posterior area)

Dental History: Root canal treatment on the maxillary right first molar (#3) had been performed by an endodontist 40 years earlier. Swelling and pain had developed a week earlier and was improving.

Significant Findings (Tooth #3): Moderate palpation and percussion sensitivity was observed upon testing. The radiographic series revealed a large diffuse radiolucency about the MB root and unfilled root canal systems with a parallel post having been placed in the palatal root. Periodontal probing depths were within normal limits with bleeding upon probing at the mesiolingual line angle area.