RESUMO
Objective: Previous research on problem-based learning (PBL) describes that videotaped observations develop meaningful insights into cognitive processes in tutorial groups. Analysis regarding the amount of prior knowledge on learning achievement has not been investigated in medical education so far, although both are key factors of PBL success. Thus, we intended to analyse videos of digital problem-based learning (dPBL) sessions, focusing on knowledge acquisition and interaction dynamics among groups with different levels of prior knowledge to reveal any distinctions. Methods: This study employed a pilot design by dividing 60 dental students into twelve subgroups with less or more prior knowledge, determined by a pre-semester multiple choice test (MCQ). The groups engaged in videotaped dPBL cases, which were examined regarding group interactions and tutor effectiveness. The learning achievement was assessed through a post-semester MCQ, an oral and practical exam. Results: The video analysis showed that dPBL groups with less prior knowledge achieved significantly higher tutor effectiveness and group interaction utterances, but that the percentage of time in which utterances occurred was similar in both groups. Related to the MCQ results, the students with less prior knowledge learned four times more than those with profound previous abilities, but no significant difference was found in the results of the oral exam and practical exam. Conclusions: The interaction dynamics in dPBL depend on the group's amount of prior knowledge. Especially groups including participants with less prior knowledge seemed to benefit from dPBL in comparison to groups with more prior knowledge. The dPBL groups acquired knowledge in different ways during the courses but, finally, all students arrived at a similar level of knowledge.