Clinical training continuity during the COVID-19 pandemic improves root canal treatment quality in dental students: a retrospective cohort study

The COVID-19 pandemic disrupted dental education worldwide, yet its impact on endodontic competence remains unclear. This study evaluated how disruptions in preclinical and clinical endodontic training affected the technical quality of root canal treatments performed by undergraduate dental students. A retrospective cohort study was conducted using the first maxillary molar root canal treatments performed by fifth-year students from the Classes of 2022, 2023, and 2024 at our university, each exposed to different pandemic-related educational disruptions. The pre-pandemic Class of 2019 served as a control. Only cases with high-quality periapical radiographs at diagnosis, working length determination, master cone fit, and obturation were included. Technical quality was assessed per European Society of Endodontology guidelines, considering obturation length, density, and procedural errors. Treatments were classified as adequate or inadequate. Differences among cohorts were evaluated using chi-square tests ( p < 0.05). A total of 324 molars were assessed: 87 (Class of 2022), 73 (Class of 2023), 100 (Class of 2024), and 64 (Class of 2019). Adequacy rates were lowest in the Class of 2022 (24.1%), followed by the class of 2023 (30.1%) and the control group (32.8%), and highest in 2024 (43.0%; p = 0.049). The technical quality of root canal treatments differed among classes exposed to different patterns of pandemic-related disruption. The highest proportion of technically adequate treatments was observed in the Class of 2024, which received uninterrupted third- and fourth-year clinical training, whereas the lowest proportion was observed in the Class of 2022, which experienced the greatest disruption to clinical training. These findings highlight the relevance of continuity in clinical training to root canal treatment quality in undergraduate endodontic education.