## 2 Materials and Methods  
The workflow for this study is presented in Figure 1. Sixty participants were recruited from a pool of second-year dental students who had the same dental educational background and practical training. The participants were allocated to one of two groups defined by the teaching methods, namely the paper-based 2D presentation method and the computer-based 3D simulation method. For randomized grouping, a pair-matching method was used that is based on the grade point average (GPA) from the students' first-year dental curriculum [20]. Partitioning into matched pairs by GPA was used to equalize the baseline covariates of learning competency of all attendees. Ethical approval for the study was granted by the institutional review board of Kyungpook National University Dental Hospital (KNUDH-2020-03-06).  
In the paper-based 2D presentation method, 30 students received the occlusion lecture using a textbook [21] and a PowerPoint presentation with 2D illustrations. The lecture consisted of the features of defective occlusion in the centric and eccentric relation of the jaw. It also included the principles for occlusal adjustments of each interference in the maximal intercuspation and medio-, latero-, and protrusive movement of the jaw (Figure 2). In the computer-based 3D simulation method, the other 30 students received 3D simulated teaching with 3D graphic dental models and computer design software (R2 CAD; MegaGen, Daegu, Korea). The 3D models with a defective occlusal scheme were created in the polygonal mesh format. The occlusion interference of each condition was adjusted in  
To assess participants' responses and feedback regarding the 3D computer-based visualization method, an attitudinal survey was conducted after the training course for the 3D simulation group (Supplementary Materials S1). The survey was comprised of five questions assessing the preference of participants on the method in terms of expected effects and satisfaction [22]. Participants were asked to respond on a scale of 1 to 5. A score toward the high end of the scale indicates a higher preference toward the method.  
Afterwards, an examination of the occlusal adjustment was conducted on the same day of class for all students to evaluate the learning effects of different teaching methods. The test consisted of eight questions for the principle of adjustment for defective occlusion in centric and eccentric relations (Supplementary Materials S2). The questions were formulated following the recommendation by the American sociological review for open- and close-ended questions [23; 24]. They were then modified based on the lectures and teaching materials provided to students in the present study. The examination results were first scored in a numeric scale of 0 to 100, and then categorized into five grades [25].  
The means and standard deviations of the survey and examination scores were calculated. Statistical comparisons between the two instructional methods were performed by using the independent \(t\) test for each question concerning the adjustment strategies for deflective occlusion in centric and eccentric relation. The agreement between the results of the survey and examination was presented using [PERSON]'s correlation coefficient and a scatterplot. All statistical analyses were carried out using statistical software SPSS (IBM SPSS Statistics, v25.0; IBM Corp., Armonk, NY, USA) at 0.05 significance level.