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.

Repair of gross perforation defects can result in long-term successful treatment

Patient: 23 year old female in excellent health

Chief Complaint: ”tooth feels swollen”

Dental History: The patient reported having had the previous root canal treatment, build-up, and crown performed by her previous dentist in Salt Lake City, Utah, 6 years prior (1994)

Significant Findings: The patient presented with severe percussion sensitivity, fluctuant swelling, Class 1 mobility, a 4mm sulcular mesiolingual defect which bled upon probing, and the following radiographic observations associated with the mandibular left first molar (tooth #19):

1. Previous root filling with weak apical radiodensity and filled short of the radiographic terminus.
2. Missed canals were suspected in each root.
3. Three previous posts were placed in each root and suspected to be perforating the furcation.
4. The periapical radiolucency was noted circumscribing the mesial root measuring 5.5mm in greatest
   diameter and a periapical radiolucency circumscribing the distal root measuring 3.5mm in greatest diameter.
5. A large radiolucency involving the furcation.