In this study, we applied the DREEM questionnaire to 3rd and 5th year students of the Integrated Master of Dental Medicine course at the IUCS, in order to assess the educational environment before and during the pandemic and compare the different perceptions between preclinical and clinical students. The purpose of this study is to detect the positive and negative aspects of the institution, subsequently promoting possible changes that enhance the satisfaction and success of IUCS students. With regard to adherence to the survey, there was a good adherence, similar to several previous studies (Mohd Said, Rogayah et al. 2009, Prashanth and Ismail 2018) with a response rate of 74.1% of the academic population of the IUCS. This fact, may be indicative that students are concerned about the EC in the institution and consider that through the DREEM questionnaire, the institute can verify the main failures, thus seeking to solve them (Whittle, Whelan et al. 2007).
In the present study, the mean total score of the questionnaire, before the pandemic, was 126.5, showing a positive response regarding the EC of the MIMD students of the IUCS. The total DREEM score at our educational institution when compared to the other studies conducted in Germany (Rotthoff, Ostapczuk et al. 2011), India (Thomas, Abraham et al. 2009), Pakistan (Ali, Raja et al. 2012), Spain (Maria, Paula et al. 2020) and Malaysia (Mohd Said, Rogayah et al. 2009),was higher. In contrast, when compared to studies in the universities of New Zealand(Foster Page, Kang et al. 2012) and Oman (Prashanth and Ismail 2018), our institution shows lower total DREEM values, which shows that although IUCS shows positive results, there is always an opportunity for improvement in order to meet the needs of students, providing an even more positive view of students towards the EC. As for the comparative analysis of the DREEM subscales, we can see that similarly to the overall score, the IUCS presents quite positive values. With regard to social self-perception and perception of learning, the IUCS showed very optimistic results, similar to the results obtained in Oman and New Zealand (Foster Page, Kang et al. 2012, Prashanth and Ismail 2018).
With regard to the academic perception of oneself and the perception of the educational environment, the IUCS is one of the institutions with the highest values, allowing us to conclude that the students consider that they are prepared to practice their profession in the future and find in the teaching institute an organized place, and in addition, it provides a calm and relaxed environment during theoretical classes and clinical activity.
In opposition, regarding the perception of the student in relation to the teachers, our institution has one of the lowest values compared to the other countries (Rotthoff, Ostapczuk et al. 2011, Foster Page, Kang et al. 2012, Prashanth and Ismail 2018), but is still considered to be "going in the right direction". These values can be explained by the fear of the shier students to talk openly with the teachers during the classes, thus inhibiting the sharing of knowledge, which may negatively influence the learning process.
When comparing the values obtained before the pandemic, between preclinical and clinical students, we found that both the overall DREEM values and the values of the different subscales were higher in the preclinical students than in the clinical students, and these differences were statistically significant and with high or very high magnitude of effect. These results may be due to the fact that fifth-year students, since they are in the final phase of the course, a crucial moment in their lives, may show higher levels of anxiety than third-year students. In this regard, the study developed by Bunmi et al. mentions that the transition from pre-clinical to clinical practice, despite being reported by students as an exciting learning phase due to changes in the context and responsibilities, is also a source of stress and anxiety among medical students, which may be related to perceptions of preparation for the clinical part (Malau-Aduli, Roche et al. 2020).
The stress factor is the factor that most influences the results obtained from the DREEM questionnaire. The MIMD is a very intense course and at the same time, very stressful, with numerous theoretical and practical assessments, which cause anxiety in students. This is particularly pronounced during the various stages of training, whether preclinical or clinical, however, it is considered to be higher when it comes to caring for the health of "flesh and blood" patients rather than phantoms with artificial teeth.
As for the period during the pandemic, the results obtained for 3rd year students were lower overall, however, there was still a "more positive than negative" response to the overall EC.
Third-year students felt the differences inherent to the COVID-19 pandemic most notably, with distinct results obtained before and during the pandemic with statistically significant differences. These values can be explained by the fact that they were completely unable to have face-to-face classes at the college, with all classes being held at a distance, through digital platforms. Therefore, they were consequently unable to be physically with friends, professors, causing a negative impact on the students' lives. Negative feelings of frustration, anxiety, anger, and boredom ended up being more frequent in the lives of these students, causing a more negative view of the EC during the pandemic.
It should be noted that the greatest difference in this group of students was reflected in the perception of learning, with lower mean scores during the pandemic compared to before the pandemic. This result may be justified by the negative view of these students, which made them consider that education did not help them develop skills for their future as dentists. In this sense, the study developed by Ahmad et al. states that although videoconferences and educational blogs are an asset in disseminating theoretical knowledge, we cannot neglect that clinical courses are designed primarily to ensure students' competence in routine medical-dental procedures. These clinical skills and expertise cannot be optimally obtained without a supervised patient treatment experience, and significant disruption of the educational process can adversely affect the development of students' competencies (Jum'ah, Elsalem et al. 2020).
In contrast, the impact of SARS-cov-2 on 5th year students during the pandemic turned out to be less significant, and in comparison, to the period before the pandemic, higher values were registered. These values may be justified by the fact that, despite the pandemic situation, the teaching activity continued, with face-to-face classes at the CESPU Clinical Unit. Despite all the imposed rules, 5th year students, when attending face-to-face classes, end up having the opportunity to socialize with their course mates, with the teachers and assistants at the clinic, or even with the patients, thus promoting a better perception of the educational environment at the faculty.
The Covid-19 pandemic caused a drastic change in the students' lives, causing a rather negative impact on the students' lives. However, despite this negative view, 5th year students started seeing patients in the clinic for the first time, after a long 3 years of pre-clinical teaching, perceiving the fear of making mistakes and the responsibility that this implies and in opposition to the fulfilment of being able to perform what they have learned during their course in the educational institution.
Another hypothesis that may explain these values is the fact that students attended internships in hospital clinics and community oral health clinics, thus providing resources that increase students' self-confidence and strengthen their social relationships among students, teachers and patients. This assumption is supported by the results obtained in the LP subscale, since mean values for the perception of learning during the pandemic were higher than those obtained before the pandemic.