The hows and whys-A new teaching model for anatomy learning supported by customized 3D printed models.

The advent of three-dimensional (3D) printing technology has enabled educators to design customized 3D printed models (3DPMs), but the current literature shows conflicting evidence regarding the impact of 3DPMs on students' knowledge acquisition. Moreover, the methodology of existing studies is limited to investigating if 3DPMs work but fail to provide insights into why and how they work. This study investigated behaviors of a cohort of 80 first-year dental students in a learning environment assisted by 3DPMs and generated design principles for 3DPMs integration in the classrooms. To observe students' behaviors and determine their achievement of the learning outcomes, a list of tasks and their respective hypothetical learning trajectories (HLTs) were developed. The HLTs were compared with the actual learning trajectories (ALTs) based on students' work, observers' notes, video recordings of the classroom and focus group interviews. Overall, there is a gradual decrease in alignment for HLTs and ALTs as the cognitive level of the task goes up. Notably, students were more likely to apply their knowledge on human prosections having learned with 3DPMs, as shown by the video creation task. The study offered several implications for the design and delivery of modern undergraduate anatomy curricula. Focus group analysis revealed that the design of the 3DPMs played a role in increasing perceived confidence, assisting quicker knowledge acquisition, and increasing students' motivation. 3DPMs play a supportive and transitional role, particularly in early stages of students' learning, in motivating them to transfer knowledge to real human prosections.