Goldberg F, et al. - In this retrospective clinical study, researchers explored the connection between unintentional overfilling and the long-term outcome of both primary root canal treatments and retreatments performed by experienced endodontists. The study included a total of 220 root canal treatments with unintentional postoperative overfilling performed by two endodontists during their 45 years of private practice. Data reported that the level of inter-observer agreement was 66.1%. Primary root canal treatments had a much higher success rate than retreatments. The only other factor that significantly affected the outcome was tooth location. The result of unintentionally overfilling root canal treatment was not related to the type of extruded material or its resorption or persistence. The persistence of extruded material was not associated with a favorable or unfavorable result.