Effectiveness of Combining SDL and CBL in Postgraduate Orthodontic Education: A Randomized Trial and Surveys

PURPOSE: Self-directed learning (SDL) is now combined with traditional case-based learning (CBL). The purpose of this study was to investigate and compare the teaching outcomes and impacts on self-assessment of the SDL-CBL teaching method and the traditional CBL-only approach for improving orthodontic postgraduate students' clinical practice ability. METHODS: We recruited orthodontic postgraduate students at a university from 2020 to 2022, randomly dividing them into an experimental group employing the SDL-CBL mode and a control group using the traditional CBL-only teaching method. Our study design included a randomized trial assessing teaching effectiveness via pre- and post-program test scores and a self-evaluation survey at three time points (before, during, and after the project). Intragroup data were compared via analysis of variance (ANOVA). RESULTS: The post-program theoretical and practical scores obtained by students in the SDL-CBL group reached a significantly higher level. Concerning the mid-term self-evaluation attributed to doctor-patient communication and diagnostic reasoning skills, there were significantly higher scores for the SDL-CBL group. The post-program test scores of most abilities related to clinical competence were significantly higher among students in the SDL-CBL group; however, students' self-assessments of manual skills indicated no significant difference between groups. Intragroup analysis revealed greater progress in humanistic cultivation during the first half of this process among students in the traditional CBL group. CONCLUSION: Overall, compared with the traditional CBL-only teaching mode, the SDL-CBL model demonstrates superior teaching effectiveness in terms of parameters assessed in performance tests and self-assessment of several clinical competence-related abilities.