Differential Diagnoses for Persistent Pain Following Root Canal Treatment: A Study in the National Dental PBRN.

Introduction: Pain present six months following root canal treatment (RCT) may be either of odontogenic or non-odontogenic origin. This is important because treatments and prognoses are different; therefore, the aim of this study was to provide specific diagnoses of patients reporting pain six months after receiving initial orthograde RCT.

Methods: We enrolled patients from the Midwest region of an existing prospective observational study of pain after RCT. Pain at six months was defined as ≥ 1 day of pain and average pain intensity of at least 1/10 over the preceding month. An endodontist and an orofacial pain practitioner independently performed clinical evaluations, which included periapical and cone-beam computed tomograph (CT) radiographs, to determine diagnoses.

Results: Thirty-eight out of the 354 eligible patients in the geographic area (11%) met the pain criteria, with 19 (50%) consenting to be clinically evaluated. As the sole reason for pain, 7 patients (37%) were given odontogenic diagnoses (4 involving the RCT tooth, 3 involving an adjacent tooth). Eight patients (42%) were given non-odontogenic pain diagnoses (7 from referred temporomandibular disorder [TMD] pain, 1 from persistent dentoalveolar pain disorder [PDAP]). Two patients (11%) had both odontogenic and non-odontogenic diagnoses, while 2 (11%) no longer fit the pain criteria at the time of the clinical evaluation.

Conclusion: Patients reporting "tooth" pain 6 months following RCT had a non-odontogenic pain diagnosis accounting for some of this pain, with TMD being the most frequent non-odontogenic diagnosis. Dentists should have the necessary knowledge to differentiate between these diagnoses to adequately manage their patients.