Healing of intra-alveolar transverse root fractures after root canal treatment limited to the coronal fragment: a retrospective study

Root canal treatment (RCT) is indicated for intra-alveolar transverse root fractures (TRFs) with pulp necrosis and root canal infection. This study evaluated fracture-line healing after RCT limited to the coronal fragment in root-fractured teeth and explored the factors associated with unfavorable healing. The hospital records of patients with TRFs were screened. Eligible cases included mature teeth with TRFs treated with RCT limited to the coronal fragment after clinical and/or radiographic findings indicated pulp necrosis with root canal infection, with at least three months of follow-up or documented earlier unfavorable healing. Healing was assessed using radiographic criteria together with clinical signs and symptoms. Kaplan–Meier analysis was the primary time-to-event analysis, and Cox regression was performed solely as an exploratory analysis. Forty-nine teeth were included, of which 43 (87.8%) showed favorable healing and six (12.2%) showed unfavorable healing. The probabilities of favorable healing were 95.6% at 1 year (95% confidence interval [CI], 89.7–100.0) and 90.1% at 5 years (95% CI, 81.3–99.9). Favorable healing differed among the three fracture-location groups ( P = 0.029): cervical-third fractures showed the lowest proportion (4/7, 57.1%), followed by apical-third (8/9, 88.9%) and middle-third fractures (31/33, 93.9%). In the exploratory multivariable Cox model, middle-third fractures had a lower risk of unfavorable healing than cervical-third fractures (hazard ratio [HR] = 0.048; 95% CI, 0.004–0.623; P = 0.020), whereas root canal filling material was not significantly associated with healing. RCT limited to the coronal fragment showed favorable fracture-line healing in most fully developed permanent teeth with TRFs. Cervical-third fracture location was associated with unfavorable healing; however, this association should be interpreted cautiously, given the small number of events. No material-specific conclusions are drawn.