Occurrence and predictors of severe pain one week after root canal treatment: the national dental PBRN PREDICT endodontic study

Objective: Root canal treatment (RCT) is effective at relieving dental pain for most patients, but a minority report severe pain during the early post-treatment period. This study aimed to quantify the occurrence of severe pain during the 1-week period after RCT among consecutive patients requiring RCT and to identify pre-operative and intra-operative predictors of post-RCT severe pain in the National Dental Practice-Based Research Network. Methods: This prospective cohort study enrolled patients across 153 general and endodontic practices. Eligible adults undergoing RCT completed surveys before and 1 week after treatment. Severe post-RCT pain was defined as patient-reported worst pain ≥7 on a 0–10 scale in the prior 7 days. Demographic, clinical, procedural, and psychosocial characteristics were collected and analyzed using logistic regression with generalized estimating equations, accounting for clustering by practice. Results: Among 1,059 patients, mean worst pain scores declined significantly from 5.3 pre-RCT to 2.6 post-RCT (p<.001). However, 14% reported severe pain at 1 week. Female sex, severe pain at time of RCT, screening positive for temporomandibular disorders, diagnosis of fibromyalgia, and having taken pain medication for tooth pain in the 7 days prior to RCT, were each significantly associated with severe post-RCT pain. Neither age, tooth type, provider specialty status, or psychosocial characteristics were independently predictive. Presence of a draining sinus tract and use of over 5x magnification were protective. Conclusion: One in seven patients reported severe pain in the first week after RCT, primarily associated with pre-operative pain factors and patient sex, underscoring the value of targeted pain management for high-risk patients. Clinical Significance: Despite overall pain reduction after RCT, 14% of patients experience severe pain at one week. Female sex, pre-existing pain, and certain comorbidities increase risk. Identifying these factors enables clinicians to implement anticipatory guidance and tailored pain management, improving outcomes and minimizing patient distress in vulnerable subgroups.