This study assessed biomedical science content acquisition from problem-based learning (PBL) and its relationship to students' level of group interaction. We hypothesized that learning in preparation for exams results primarily from individual study of post-case learning objectives and that outcomes would be unrelated to students' group involvement. During dental curricular years 1 and 2, student-generated biomedical learning issues (LIs) were identified from six randomly chosen PBL cases. Knowledge and application of case concepts were assessed with quizzes based on the identified LIs prior to dissemination of the learning objectives. Students and facilitators were surveyed on students' level of group involvement for the assessed LI topics. Year 1 students had significantly higher assessment scores (p=0.0001). For both student classes, means were significantly higher for the recall item (Q1) than for the application item (Q2). Q1 scores increased along with the student's reported role for Year 1 (p=0.04). However, there was no relationship between the student's reported role and Q1 for Year 2 (p=0.20). There was no relationship between the student's reported role and Q2 for Year 1 (p=0.09) or Year 2 (p=0.19). This suggests that students' level of group involvement on the biomedical learning issues did not significantly impact students' assessment performance.