Complex Anatomy-Fused DB-P and MB-P Roots

Patient: 64-year-old male with elevated cholesterol and high blood pressure

Chief Complaint: History of pain associated with right maxillary first molar, presented asymptomatic, but felt sharp associated pain when at high altitude.

Dental History: Previous crown and subsequent repair of caries within the previous 5 years (Tooth #3)

Significant Findings: Class 1 mobility and no response to cold thermal stimulation. The radiograph shows a periapical radiolucency circumscribing the root apices and pulp chamber calcification (Tooth #3).

Diagnosis: Necrotic pulp, asymptomatic periapical abscess with radilucency (Tooth #3)

Prognosis: Good

Treatment Plan: Nonsurgical Root Canal Treatment in 2 Steps (Tooth #3)

Treatment Discussion and Special Considerations: This patient presented with very challenging root anatomy requiring endodontic treatment. Dr. Ronald Ordinola Zapata has collected and processed beautiful fused root examples as part of his research. The fused DB-P root form is a common root anomaly present in maxillary molars. This type of anomaly is not commonly recognized and when ignored and not treated results in poor debridement and incomplete root canal treatment more likely to fail. The radiographic presentation of this case suggested very narrow roots with a "double root" image portraying this type of anatomy. Confirmation of the anomalous root form was verfied with a CBCT scan taken incidentally to check the healing of the endodontics performed on the adjacent second molar performed 11 years earlier. Endodontic access revealed a wide fin connecting the P and DB orifices and on the second visit a "white dot" of calcium hydroxide marked the very subtle entry point of the DB2, which was not noted on the first visit a month earlier. K-files placed in the DB1, DB2, and P canals revealed the P canal to be separate but he DB2 crossed over horizontally and merged with the DB1.

As in previously discussed complex anatomical cases, multiple recapitulations with precurved hand files and copious irrigation essential steps for predictable treatment success.

Key Learning Points:

1. A preoperative radiograph showing a "double" root image is often a clue to a fused root form.
2. The fused DB-P root anomaly is common and usually unrecognized
3. CBCT exam helps to understand anomalous root presentations