Is online-only learning as effective as blended learning? A longitudinal study comparing undergraduate students' performance in oral radiology.

INTRODUCTION Blended learning seems to be an effective teaching concept in oral radiology. During the COVID-19 pandemic, blended learning shifted towards online-only learning. The aim of the present study was to compare the effectiveness of pandemic online-only and pre-pandemic blended learning in three consecutive oral radiology courses (C1, C2 and C3) and to examine whether additional video-based e-learning modules (VBLMs) had a positive impact on undergraduate students' performance during pandemic semesters. MATERIALS AND METHODS Data from 205 undergraduate dental students participating either in a blended learning or an online-only learning concept were analysed. Pre-pandemic blended learning comprised face-to-face seminars and access to an oral radiology platform (ORP). Pandemic online-only learning comprised online seminars, access to the ORP and additional VBLMs (two VBLMs for C1, four VBLMs for C2 and six VBLMs for C3). Through standardised e-exams at the beginning and end of each semester, performance in final exams and knowledge gain were compared between the two groups. RESULTS No significant differences in scores in final exams (p = .11) and knowledge gain (p = .18) were found when comparing the pre-pandemic and pandemic groups. On course level, however, students receiving a lower number of VBLMs performed significantly worse in final exams (C1: p < .01, C2: p = .02) and showed inferior knowledge gain (C2: p < .01) during the pandemic. CONCLUSIONS Within the limitations of the study, the present investigation confirmed that pandemic online-only learning involving VBLMs might be as effective as pre-pandemic blended learning.