Test procedure
Both groups completed a formative, unannounced pretest with 20 items at the beginning of the course after the first week. The theory taught included general dentistry, materials science, prosthodontics and dental instruments and were not the subject of the seminars and lectures. A total of two and zero points were awarded for each correct and incorrect answer, respectively. The maximum achievable score for each test was set at 40.After the initial assessment, group IG received the app to train for three weeks with anonymized and randomly generated identities (IDs) and passwords. During this intervention period, group CG received the same questions as in the app as a printed booklet for self-training and self-assessment. During the test period, the app recorded usage statistics. It recorded how many questions and games of the different game modes were played and whether the answers given were correct or incorrect. After the intervention phase, both groups participated in a formative, unannounced post-test with 20 tasks similar to those of the pretest. After the post-test, the CG groups had access to the app for three more weeks with anonymized and randomly generated IDs and passwords. At the end of the course, both groups completed standardized questionnaires to evaluate the app. The items consisted of a six-point Likert scale, with extremes of "strongly agree" and "strongly disagree". Additionally, participants were asked in which situation and how often they played with the app and which German school grade they would rate the app. The app's usability was tested using the System Usability Scale (SUS) [I think that I would like to use this system frequently.I found the system unnecessarily complex.I thought the system was easy to use.I think that I would need the support of a technical person to be able to use this system.I found the various functions in this system were well integrated.I thought there was too much inconsistency in this system.I would imagine that most people would learn to use this system very quickly.I found the system very cumbersome to use.I felt very confident using the system.I needed to learn a lot of things before I could get going with this system.