The purpose of this retrospective study was to evaluate the success rate of intentionally replanted mandibular second molar with C-shaped canal configurations and to access the impact of preoperative periapical lesion on the success of intentional replantation procedure.

This retrospective chart review study evaluated 52 intentionally replanted mandibular second molar teeth treated at Seoul National University Dental Hospital Department of Conservative Dentistry from January 2005 to December 2007. Seventeen teeth were lost for the follow-up, and another 6 teeth did not meet inclusion criteria of C-shaped root canal configurations. Healing outcome such as success, uncertain healing, and failure after follow-up was evaluated by clinical criteria and radiographs.

The overall success rate was 72.4% for the 29 intentionally replanted C-shaped mandibular second molars. The success rate of replanted teeth with preoperative periapical lesions was similar to that of replanted teeth which have no periapical lesions.

Therefore, root canal treatment failure on C-shaped mandibular second molar can be predictably treated by intentional replantation regardless of the presence of periapical lesion.

This study aimed to assess prospectively the clinical outcome of nonsurgical endodontic treatment and identify patient- and tooth-related factors, rather than treatment-related factors, that were the best predictors of this outcome.

The inception cohort comprised 441 teeth (320 patients) and 175 teeth (123 patients) were followed up for 1-2 years. Age, gender, presence of medical disease, number of canals, previous endodontic treatment, presence of sensitivity and pain, pulp vitality, swelling or sinus tract of pulpal origin on the gingiva, periapical radiolucency and tendency of unilateral bite on the affected tooth were recorded at treatment start.

The outcome was classified on the basis of periapical radiolucency as healed or non healed. The overall healed rate in these cases, including nonsurgical retreatment, was 81.1%. Four tooth-related factors had a negative impact in the bivariate analysis: previous endodontic treatment, necrotic pulp, preoperative gingival swelling or sinus tract of pulpal origin, and preoperative periapical radiolucency. Stepwise logistic regression analysis including patient-, tooth-related factors and level of the root canal filling as a treatment-related factor showed that preoperative gingival lesion (odds ratio [OR]: 4.4; p = 0.005), preoperative periapical radiolucency (OR: 3.6; p = 0.011), and ≤ 1-2 mm under root filling length (OR: 9.6; p = 0.012) were significant predictors of failure.

A preoperative gingival lesion of pulpal origin can influence the outcome of nonsurgical endodontic treatment in addition to preoperative periapical radiolucency.