Outcome of single‐ versus two‐visit root canal retreatment in teeth with periapical lesions: A randomized clinical trial

Abstract Aim The aim of the study was to evaluate the clinical and radiographic outcome of single‐visit root canal retreatment and compare the results with conventional two‐visit root canal retreatment as control group. Methodology One hundred root canal‐treated, single‐rooted asymptomatic teeth with periapical lesion were retreated by one operator. Fifty of the teeth were randomly assigned to the single‐visit group and the others were treated in two visits. In both groups, root canal filling material was removed, and re‐instrumentation of the root canal was performed using step‐back technique with hand files using 2.5% NaOCl and 5% EDTA as irrigants. In the single‐visit group, 5 ml 2% chlorhexidine (CHX) were applied as the final irrigation and in the two‐visit group, calcium hydroxide paste was placed into the root canal as an interappointment dressing. All root canal obturations were performed with lateral compaction. All patients were followed up for 24 months. The success was determined depending on both healed and healing cases. The chi‐square or Fisher's exact test was used to analyse the differences between the groups for success rates and the factors affecting the outcome. Results The recall rate was 89 (89%). At 24 months, 39 teeth (88.6%) were considered as healed, three teeth (6.8%) as healing, and two teeth (4.5%) were identified as failed in the single‐visit group, while in the two‐visit group 39 teeth (86.7%) had healed, two teeth (4.4%) were scored as healing, and four teeth (8.9%) as failed. There was no statistically significant difference in the success rates between the two groups ( p > .05). Size of the lesion and the preoperative length of root canal filling had a statistically significant impact on the outcome ( p < .05). Conclusion No statistically significant difference was observed in terms of healing in 24‐month follow‐up of retreatments completed in single visit or two visits in asymptomatic teeth with periapical lesions. The size of the periapical lesion and initial apical level of root canal filling have affected the outcome of root canal retreatment.