INTRODUCTION

Two years have passed since the onset of widespread infection by SARS-Cov-2 (COVID-19) worldwide ¹ . In most countries, the teaching -learning process switched from a face-to-face relationship to a mainly virtual environment ² . While some authors report general acceptance of online-based dental education ² , others report higher rates of dissatisfied students ³ . Given the practical nature of dental education, authors suggest the need for continuous research of students’ perceptions regarding the current transitions in the teaching-learning process during COVID-19 times ⁴ . To achieve a more comprehensive perspective of students’ perception, however, research should be country-specific, especially because of the global differences in the curricula and educational approaches. In 2021, a study across 34 European countries highlighted dental students’ concerns regarding clinical experience and the skills needed to become dentists ³ . In the same year, a study on 779 Brazilian dentistry undergraduates corroborated students’ dissatisfaction with the transition between traditional education and e-learning ⁵ .

The situation of Brazilian dental education in COVID-19 times is particularly relevant because in 2020, the country was ranked second amongst the countries with the highest numbers of confirmed cases ⁶ . Moreover, Brazil has nearly 370,000 dentists ⁷ (estimated as 17% of the dentists in the world) and at least 374 dental schools offering 47,192 admission places ⁸ for students. The effects of COVID-19 on the educational process of Brazilian undergraduate dentistry students could eventually lead to potential harm of great magnitude given the number of professionals entering the market every year.

In specific fields of dentistry, computer-based classes are essential. Such is the case of Oral Radiology -a field that requires constant updates and training with state-of-the-art technology. Hence, students of Oral Radiology may accept transitions to e-learning more easily. A systematic literature review ⁹ found out that e-learning strategies used in the teaching-learning process of Oral Radiology seem to be as effective as other traditional approaches, such as lecture-based learning. Strategies used to bring online dentistry lessons closer to reality include case-based learning, problem-based learning, and research-based learning ^{2, 10} . For image interpretation (an essential component of Oral Radiology), the available online tools could enable proper teaching and even enhance students’ interaction with image analysis. On the other hand, practical training in radiographic techniques for image acquisition could be negatively impacted after the switch to the online environment ¹¹ . In these cases, demonstrative instructions followed by laboratory practice with a restricted number of students (per group), and the use of facilities dedicated to oral radiology, including phantom heads, would be beneficial when teaching returns to being part online and part face-to-face ¹² . Striving for the best conditions for students’ educational development, however, depends on the available pedagogical solutions. Understanding the perspective of undergraduate dentistry students regarding the ever-changing educational scenarios experienced during the COVID-19 pandemics is fundamental to establishing more effective strategies for the teaching-learning interface in Oral Radiology. The aim of this study was to assess the perspective of students regarding the teaching-learning process of Oral Radiology before and during the pandemic.

MATERIAL AND METHODS

Variables and measures

A self-administered questionnaire was tailored for the present survey. Following the scientifie literature, the questionnaire was designed as closely as possible to the recommendations established for survey research ¹⁴ . The questionnaire consisted of 21 questions divided into three groups: A) General information about the students’ demographic data (5 questions); B) Speeifie questions related to the students’ teaching-learning experiences in the pre-pandemic period (8 questions); and C) Speeifie questions related to the students’ teaching-learning experiences in the post-pandemic period (8 questions). Question structure was dichotomous (the question about whether they had had contact with e-learning tools before the pandemic) or multiple-choice (students should select a single answer). Questions in sections B and C were mirrored for the period pre- and trans-pandemic. This approach enabled the questions to be answered by the same students - so they could report on experiences regarding the Oral Radiology teaching-learning process at two different times (before/pre and during/trans pandemic) -creating a dependent association between answers (dependent variables between sections B and C) ( Table 1 ). Because institutional activities were returning to face-to-face during the pandemic period, the questionnaire was provided on-campus and separately to students of the second, fourth, and sixth semesters of the undergraduate course. The main researcher supervised the application of the questionnaire in class. All the students were adults (age >18 years old) and expressed their consent to participate in the study within a signed informed consent applied before the questionnaire.

Table 1 Self-administered questionnaire provided to undergraduate students in the 2nd, 4th, and 6th semesters of the dentistry course, regarding their perspective of the Oral Radiology teaching-learning process before and after the COVID-19 pandemic. 

RESULTS

General information about the students’ demographic data (Questionnaire section A) showed that the questionnaire was answered by 31 (27.92%) male and 80 (72.08%) female students. Forty students (14 males and 26 females) were in the 2nd semester, while 42 (11 males and 31 females) and 29 (6 males and 23 females) were in the 4th and 6th semesters, respectively. Most of the students were 18 to 20 years old (75.67%), followed by students aged 21 to 24 years (21.62%), or over 25 years (2.71%). Most students did not know their internet speed at home (41.44%). Of the students that did know, most (25.22%) reported a speed between 110 and 150 Mb/s. Regarding the devices used to access e-learning content, notebooks (58.55%) and smartphones (27.02%) were the most prevalent. Desktops were only reported by students in older age categories ( Table 2 ).

Table 2 Descriptive assessment of the general information about the students’ demographie data (questionnaire section A) 

When asked about the quality of Oral Radiology teaching, most students of both the 4^th and 6^th semesters rated it as modérate or good before and during the pandemic. When students were asked about their performance in the Oral Radiology module, they tended to rate it as modérate or good. Particularly for students in the 6^th semester, there was a predominance of “good” ratings (>41%) both before and during the pandemic. Students in the 4^th semester considered the structure of the Oral Radiology module to be good before the pandemic, but moderate during the pandemic. Most students in the 6^th semester rated the module structure as modérate at both times, and students that rated the module as good and very good (>24%) maintained their opinion. Nearly 80% of the students in the 4^th and ó^th semesters had not had any contact with e-learning tools before the pandemic, becoming more familiar with them during the pandemic ( Table 3 ).

Table 3 Students’ responses related to their experiences with the Oral Radiology teaching-learning process before and during COVID-19 pandemic (Part 1) 

When asked about their opinión of e-learning for Oral Radiology, most students in the 4^th and ó^thsemesters changed their opinion from modérate importance (before the pandemic) to important (during the pandemic), with a threefold increase in the importance of the module detected in both groups. The amount of time that students spent online for non-academic reasons remained the same before and during the pandemic. Most students (60-70%) reported a non-academic online time of 1-6 hours/day. In contrast, the time spent online for academic reasons was initially longer than for non-academic reasons, and increased during the pandemic. Among 4^th semester students, those reporting online time from 7 to 10 hours doubled. Among students in the 6^th semester, the number of students spending 7-10 hours online for academic reasons increased almost 5 times. Students’ opinions regarding the assessment system of the module remained unchanged before and during the pandemic ( Table 4 ).

Table 4 Students’ responses related to their experienees with the Oral Radiology teaohing-learning proeess before and during COVID-19 pandemic (Part 2) 

Stuart-Maxwell tests revealed statistically significant differences between students’ opinions before and during the pandemic when they were asked about the structure of the Oral Radiology module (p = 0.008, statistically significant for the students in the 4^th semester only); their previous experience with e-learning (p < 0.001 for both groups of students); their thoughts related to the importance of online learning for Oral Radiology (p < 0.001 and p = 0.03 for students in the 4^th and 6^th semesters, respectively); and the time they spent online for academic purposes (p = 0.015 and p = 0.002 for students in the 4* and 6* semesters, respectively) ( Table 5 ).

Table 5 Comparison of students’ responses related to their experiences with the Oral Radiology teach-ing-learning process before and during the COVID-19 pandemic 

DISCUSSION

Research on students' perception of learning experiences serves as a quality control measure to understand the effects of the teaching process in practice. COVID-19 changed the way lectures were given, creating the need for immersion in the online environment. The concern of educational institutions regarding the quality of learning-teaching experiences increased worldwide, especially because the measures adopted as teaching Solutions to pandemics were understood as temporary ¹⁵ . Hence, it is the objective of scientific studies to investigate and possibly predict whether the online Solutions will continué to be used in the long term, in a post-pandemic future. The present study assessed the perception of undergraduate students regarding the experience with the Oral Radiology teaching-learning process before and during the pandemic.

The preliminary outcomes of this study show that most students use notebooks during the online lectures, while others use tablets or smartphones. These (recent) technologies are compatible with the age of the sample (over 75% of the students were 18 to 20 years oíd). Older students reported the use of desktop personal computers. Recent studies mention all these technologies as being useful during online activities ¹⁶ . More importantly, the student must be able to interact with the lecturer and the instructor using audio and video tools. From desktop personal computers to tablets, the equipment reported by the students enables access to the available technology to particípate in online activities. As % of the students had internet speed at home of 110-150 Mb/s, and almost 41% had access to internet even though they did not know their internet speed, it can be estimated that home facilities for online learning were available. Thus, it is necessary to enquire into students' perceptions of the teaching component. Most of the ratings of the Oral Radiology teaching quality were modérate to good. The main difference was observed between students of the 4^th and 6* semesters. In the former, ratings were predominantly good before the pandemic and became modérate during it. In the latter, over 40% of the students rated the quality as good both before and during the pandemic. These differences may be explained by the previous academic experiences of sénior students (6* semester) compared to students in earlier stages of the dentistry course. The sénior students had already experienced practical activities on-campus when the pandemic began. In contrast, the 4^lh semester students were just beginning their clinical practice when they had to move to an online environment. This change may have interfered with the plans they had when they initially enrolled in the dentistry course. However, the educational structure worldwide is currently progressively moving back to “normal” and (following this rationale) students’ perception of Oral Radiology teaching may become more positive over time. Some authors ¹⁵ report that students’ perception of the effectiveness of face-to-face classes can influence their desire to return (or not) to on-campus activities. Consequently, if pre-pandemic ratings of students of the 4^lh semester were predominantly “good”, a decrease to “modérate” is to be expected because the students certainly wish to return to on-campus activities. Secondarily, these outcomes corrobórate the quality of traditional (face-to-face) teaching of Oral Radiology at the institution considered for this study.

Despite the students’ interest in face-to-face activities interpreted between the lines of our outcomes, they seem to understand the importance of online teaching of Oral Radiology during the dentistry course. Their perception of the importance of online teaching increased up to three times during the pandemic (p<0.05). The rationale behind this phenomenon may be explained in two ways: I) students’ own perception of the content of the module (which is relevant to supporting their studies during the dentistry course); and II) students’ desire to continué their studies without a gap in time during the pandemic (hence, online tools are important to enable continuous academic training). It must be noted that online teaching of Oral Radiology is not only important because of the pandemic period. In 2012, some authors ¹⁷ demonstrated the significant role of blended teaching strategies as effective tools compared to traditional face-to-face (only) strategies. Blended teaching may figure as a strong approach in the post-pandemic period, especially because it can combine the advantages of online and face-to-face activities (e.g., online theory and face-to-face practice). The literature ¹⁸ advocates the possibility of fully implementing radiological content via e-learning methods and corroborates, once more, the importance of online teaching as part of an integrated training process in dentistry. More recently, a systematic literature review ¹⁹ indicated that most studies on the use of e-learning in undergraduate dental radiology curricula may lead to an enhancement of the learning process. However, case-specific strategies must be designed considering the facilities available at the higher education institutions.

The reduced clinical experience emerging from the transition from the face-to-face to online stmctures is of major concern to Oral Radiology. Some authors ²⁰ have suggested a broad variety of digital resources for teaching, such as Zoom, Blackboard, and Google applications. Others ²¹ have suggested the implementation of online joumal clubs and case discussions to trigger student engagement. The current technology available to students and instmctors provides a scenario which is very different from the past ²² , in which professionals were not fully familiar with digital resources, and the access to online Solutions in radiology was scarcer. The present study shows that students’ perception of the Oral Radiology teaching-learning process may change before and during the COVID-19 pandemic. Lessons leamed during this period should be considered prior to strategic planning and preparation for the upcoming post-pandemic educational system - in which on-campus activities are returning.

Future research should be designed to assess student perception after the full return to face-to-face activities, and to understand potential changes in curricula as a result of the COVID-19 pandemic. Additionally, prospective research planning should take into account students’ individual needs regarding their professional skills developed (or underdeveloped) during the dentistry course, which might lead to an increase in specialized postgraduate training ²³ . Finally, sampling individuáis from other semesters and additional higher education institutions (prívate and public) could improve the overview of students’ perceptions and lead to a more comprehensive strategy for managing the Oral Radiology teaching-learning process in challenging situations such as pandemics.

In conclusión, students’ perceptions of the Oral Radiology teaching-learning process during the

CO VID-19 pandemic changed from the pre-pandemic to trans-pandemic periods. In general, students of the 2^nd, 4^th and 6^th semesters had a predominantly positive perception of the Oral Radiology teaching-learning process. The COVID-19 pandemic led to stronger student interaction with e-learning tools and increased students’ perception of the importance of online education in times of social distancing.