Background: While closed-book examinations (CBEs) have traditionally been implemented in dental education, open-book examinations (OBEs) are being introduced for the purpose of acquiring higher levels of knowledge and promoting long-term memory. This study examines whether it is effective to use a blended assessment of CBEs and OBEs for dental students to reduce test anxiety and enhance academic performance.

Methods: Using a quasi-experimental research method, a blended assessment that combined CBEs in class and OBEs online was designed for a dental course. In 2020, when the pandemic was at its peak, student assessment was ineffective, and the 2020 cohort was omitted for our study; instead, two cohorts of predoctoral dental students (N = 178) enrolled in Restorative Dentistry in the spring semesters of 2019 and 2021 were included in the study. These students were informed about the experimental design, and they provided written consent for data collection, thereby voluntarily participating in the survey. Their self-perceived responses to open-ended survey questions on assessment methods were qualitatively analyzed.

Results: There was no significant difference in test anxiety between the CBEs and OBEs at the p-values of 0.001 in all items. Traditional and blended assessment showed a similar trend of lower scores in midterm exams compared to higher scores in final exams, thus discriminating against students' performances. In particular, a low-achieving group was better predicted by a blended assessment. An analysis of the students' self-perceived responses produced highly topical themes, including exam burden, learning effects, and fairness issues.

Conclusions: This study confirmed the feasibility of blended assessment that can be implemented in online and in-person educational environments. Moreover, it can be used as the groundwork to develop new models of assessment in dental education.