Table 2.

Eligibility criteria based on PICOS framework i.e. p = population, I = intervention, C = comparison, O = outcomes, S = studies

	Inclusion criteria	Exclusion criteria
P	Studies conducted among dental students at any stage of undergraduate radiology education	Postgraduate students, instructor, faculty staff and clinicians Not dental or medical under graduate students.
I	Studies that explored the effect of either e-learning or blended learning teaching approaches. E-learning intervention that were web-based educational software, online Power point slides, online documents, online tests, and online interactivity.	Not exploring the effects of e-learning or blended learning intervention. E-learning intervention that were based on video-conferencing, television or social media. Studies not involving online or computer-based activities i.e. occurring mainly in simulation laboratories. Studies about the development of computer technologies or software, but not applied directly to dental students
C	Studies that involved a comparison of either e-learning or blended learning with or without traditional learning OR just the evaluation of e-learning or blended learning intervention
O	Studies that involved the investigation of learning outcomes related to knowledge content, learning of clinical skills (radiologic and radiographic) performance and assessment of student’s knowledge. Studies that explored the learning outcomes related to student’s attitudes, student’s preference and student’s satisfaction in the learning activity.	Studies which did not report quantitative or qualitative learning outcomes related to these two domains
S	Studies such as randomized, non-randomized and cohort studies.	Studies in which e-learning or computer technologies were not used as a part of the education content delivery but only for administrative purposes; reviews, conference abstracts, book chapters were excluded.