Differential diagnoses for persistent pain after root canal treatment: a study in the National Dental Practice-based Research Network.
BACKGROUND
Pain present 6 months after root canal treatment (RCT) may be of odontogenic or nonodontogenic 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 6 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 6 months was defined as ≥1 day of pain and average pain intensity of at least 1 of 10 over the preceding month. An endodontist and an orofacial pain practitioner independently performed clinical evaluations, which included periapical and cone-beam computed tomographic radiographs, to determine diagnoses.


RESULTS
Thirty-eight 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 and 3 involving an adjacent tooth). Eight patients (42%) were given nonodontogenic pain diagnoses (7 from referred temporomandibular disorder pain and 1 from persistent dentoalveolar pain disorder). Two patients (11%) had both odontogenic and nonodontogenic diagnoses, whereas 2 (11%) no longer fit the pain criteria at the time of the clinical evaluation.


CONCLUSIONS
Patients reporting "tooth" pain 6 months after RCT had a nonodontogenic pain diagnosis accounting for some of this pain, with temporomandibular disorder being the most frequent nonodontogenic diagnosis. Dentists should have the necessary knowledge to differentiate between these diagnoses to adequately manage their patients.
Division of TMD and Orofacial Pain, School of Dentistry, University of Minnesota, Minneapolis, Minnesota; Department of Neurology, Medical School, University of Minnesota, Minneapolis, Minnesota; HealthPartners Institute for Education and Research, Bloomington, Minnesota. Electronic address: nixdorf@umn.edu.
Donald R
DR
Nixdorf
Private Practice, The Dental Specialists, Lake Elmo, Minnesota; Division of Endodontics, School of Dentistry, University of Minnesota, Minneapolis, Minnesota.
Alan S
AS
Law
Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota.
Mike T
MT
John
Private Practice, Norfolk, Virginia.
Radwa M
RM
Sobieh
Dental Public Health, Portland, Oregon.
Richie
R
Kohli
Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota.
Ruby H N
RH
Nguyen
D059350:Chronic Pain / Q000175:diagnosis; D015331:Cohort Studies; D005157:Facial Pain / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011861:Radiography, Dental; D012390:Root Canal Therapy / Q000009:adverse effects*; D014070:Tooth / Q000000981:diagnostic imaging
Chronic; diagnosis; pain; root canal treatment; temporomandibular disorders; tooth