Dental students’ and lecturers’ perception of the degree of difficulty of caries detection associated learning topics in Brazil

Purpose: It aimed to explore the degree of difficulty of caries-detection-associated-topics perceived by dental students and lecturers as pedagogical step in the development of learning objects for e-learning. Methods: A convenience sample comprising ninety-eight subjects from different academic levels (undergraduate/graduate students and pediatric dentistry lecturers) participated. Two spreadsheets (isolated/relative) were created considering key topics in the caries detection process. The isolated evaluation intended to explore each topic in an isolated way, while the relative intended to classify, comparatively, the participants’ perceived difficulty per topic. Afterwards, data were analyzed. All values on spreadsheets were combined obtaining the subject’s final perception. Associations between the subjects’ degree of the perceived difficulty and academic level were estimated. ANOVA was used to determine differences regarding the perception among evaluated topics in distinct groups. Results: Caries histopathology and detection of proximal carious lesions were the topics perceived as the most difficult in the process of caries detection by both students and lecturers. Differentiation between an extrinsic pigmentation and a brown-spot (caries lesion) as well as differential diagnosis between caries and enamel developmental defects or non-carious lesions were considered as more difficult by undergraduates in comparison to graduates/lecturers (regression-coefficient=14.54; Standard Error=3.34; P<0.001 and 8.40, 3.31, and 0.01 respectively). Conclusion: Topics as histopathology and detection of proximal caries lesions were identified as the most difficult despite the academic level. However, some topics are differently perceived according to the group. These results are useful for developing pedagogical material, based on the students real learning needs/expectations.


INTRODUCTION
Dental caries is still one of the most prevalent chronic dis eases in the world and represents a considerable health prob lem for many populations and its governments [1]. In this sense, adequate caries diagnosis is fundamental for planning and implementing health policies looking for the control of the disease and to respond to the necessity of delivering an improved education in Cariology for dental students as future practitioners [2]. Several systems for caries detection, a part of the diagnostic process, have been used in the world providing important information about the disease and also guiding professionals in making treatment decisions [3,4]. Nowadays, one of the most spread and used systems is the ICDAS (Inter national Caries Detection and Assessment System), which was idealized in 2002 as an attempt to standardize and global ize the diagnosis of dental caries [5]. Although this system has shown to be useful and to improve the accuracy of the process [6], developing teaching tools are important and necessary to achieve and disseminate effectively new concepts and para digms, facilitating their understanding and use and possibly, http://jeehp.org J Educ Eval Health Prof 2015, 12: 56 • http://dx.doi.org/10.3352/jeehp.2015. 12.56 reducing its difficulty into the clinical scenario.
Learning processes involving theory and practice in health sciences have been reported difficult especially for the transla tion of theoretical concepts as well as visual appreciation of the taught methods into clinical practice [7,8]. Due to that, the development of educational tools based on the student/ lecturers' perception of the difficulty of associated concepts has been considered necessary. Thus, the aim of this study was to describe the important pedagogical steps that were designed and applied prior to the development of a teaching tool of the Caries lesion development and the detection of lesions using the Information and Communication Technologies (ICT). We intend to show that even knowing that ICT sophisticated tools can be very useful; they may not achieve a successful learn ing by themselves, unless they are preceded and supported by pedagogical planning.

METHODS
This project was developed in collaboration between the School of Medicine and the School of Dentistry from the Uni versity of Sao Paulo. This is the first phase in the development of a Caries lesion development and the detection of lesions learning model using the Virtual Man Project and the ICT.

Participants
A crosssectional study was conducted with a convenience sample of undergraduate and graduate students as well as lec turers at the Department of Orthodontics and Pediatric Den tistry, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil. All volunteers signed an informed consent for partici pation.
Participants comprised different academic levels (under graduate students vs. graduate students/pediatric dentistry lecturers). Last year dental undergraduate students who at tended fulltime or nighttime course at our School in 2013 were invited to participate. They were at their final course stage, had been exposed to all curricular contents regarding Cariol ogy and participated of an eighthour theoretical/practical ac tivity (lecture and laboratory) concerning caries diagnosis and lesions' detection using the ICDAS during their last semester. Regarding graduate students and lecturers, the main differ ence between them was the higher clinical and teaching expe rience of the latter in comparison to graduate students. How ever, both groups were already involved in teaching and train ing activities in the field of Cariology.

Setting and data collection
In order to learn and understand the caries lesion detection process using a visual scoring system such as the ICDAS, it is necessary to have previous knowledge of the physiopathology and development of the caries disease. Thus, considering it as a knowledge unit, our first step was to determine key topics involved in the caries disease physiopathology and the diag nosis process. Two spreadsheets were created aiming to ex plore the participants' perceptions of the difficulty regarding competences and skills expected from an undergraduate stu dent related to the performance of caries detection adequately. These topics has been recently discussed within one of the do mains that represent the broad categories in Cariology, includ ed in the First Consensus Workshop on the development of a European curriculum in Cariology for undergraduate students [9]. The addressed caries lesiondetection topics are presented in Table 1.
The first spreadsheet (an isolated evaluation of topics) in tended to explore each topic in a single way. Participants had to weigh their level of difficulty in learning for each topic on a scale from 1 to 5, where 1 = extremely difficult, 2 = very diffi cult, 3 = difficult, 4 = not difficult and 5 = easy. The second one (a relative evaluation of topics) intended to classify, among the explored topics, the participants' perceived difficulty. They had to score each item from 1 to 11 (total of included topics), considering 1 = most difficult and 11 = easiest to be learned. The spreadsheets were completed by participants in a single session, after explanation of the methodology. Afterwards, the results were tabulated and analyzed to explore differences in the evaluations per groups.
For analysis, groups were merged according to their level of academic background, all undergraduate students (from full time and nighttime courses) as well as the graduate/lectures groups. Firstly, spreadsheets were independently analyzed and afterwards, and to obtain a final score per participant, scores from both evaluations per topic were multiplied as an attempt to combine both isolated and relative assessments.

Statistical analysis
Associations between participants' degree of per ceived difficulty and level of academic background, were estimated by Poisson and Linear Regression. This depended on the nature of the variables. Re peated measures analysis of variance was used to de termine differences regarding the perception among evaluated topics in groups. A level of significance of 5% (P< 0.05) was adopted.

Ethical approval
The present study was evaluated and approved by the Ethical Committee for Research in Human Sub jects, Dental School, University of Sao Paulo, Brazil under the protocol 206.345/ 2013.

RESULTS
Ninetyeight subjects agreed to participate in this study. Thirtysix were undergraduate students from the fulltime course and thirtyone from the night time course. Sample also comprised twentyfour graduate students in Pediatric Dentistry (five MSc and nineteen PhD students) as well as seven senior lecturers in/from the same area.
No significant differences were found in the de gree of perceived difficulty per topics between un dergraduate students from fulltime and nighttime courses. Graduate students and lecturers groups show ed no differences in the isolated evaluation of diffi culties regarding the key topics. However, graduate students scored lower the histopathology of dental caries than senior lecturers both in relative (P = 0.01) and final (combined) score assessments (P = 0.05).
Undergraduate students reported a significantly greater difficulty in comparison to graduate students/ lecturers regarding visual detection of caries lesions in smooth and occlusal surfaces; differentiation of extrinsic pigmentations and brown spot caries le sions as well as in differential diagnosis between car ies lesions and enamel developmental defects or non carious lesions (Table 2). This trend was mostly ob served for all manners of assessing subjects' percep tion of their difficulties (Table 2 and Fig. 1). When the relative and combined assessments were consid ered, the tactile detection of lesions in smooth sur faces was considered easiest by graduate students/ lecturers than for undergraduate students.
For undergraduate students, several topics were perceived as having a higher level of difficulty, as ex posed in Fig. 1. Among these topics, we can highlight the as pects related to examination of proximal caries lesions, differ ential diagnostic between caries lesions and other manifesta tions (pigmentations/defects), correlation of clinical examina tion and histopathology of caries or radiographic signs of car ies lesions (Fig. 1). On the other hand, for graduate students/ lecturers, only part of these topics, as histopathology of caries and the visual and tactile detection of caries lesions in proxi mal surfaces were the topics reported as the most difficult to be learned (Fig. 1).

DISCUSSION
This is the first study that explores the subjects' degree of difficulty of learning topics associated to caries detection based on both students' and lecturers' perception. It aims the plan ning of learning objects development based on students' real needs/expectations in order to stimulate the ideal achievement of knowledge and skills to perform this step clinically.
The main difference, concerning perceived difficulty was observed between groups with different levels of academic background. No differences were identified in the perceptions of undergraduate courses regardless time period (fulltime and nighttime) that is why data regarding these students were merged for analysis. It could be assumed that, a student that has not been recently taught about the explored topics may perceive them as difficult as those who did. In fact, those as pects, perceived as the most difficult, may not reflect its degree of knowledge [10]. On the other hand, we could speculate that recognizing the perceived difficulties could contribute, not only for planning the contents of further teaching/learning in terventions, but also motivate future learners, since their diffi culties could be contemplated in learning tools.
Though one can consider that graduate students and lectur ers groups have different levels of expertise in the caries detec tion process, graduate students in our school have received theoretical and practical training in Cariology as part of their background. In addition, they also act as trainees and tutors of undergraduate students in the laboratory and clinic in differ ent topics including Cariology, corroborating their experience in this field and balancing possible divergences. Our results confirm this assertive, since graduate students and lecturers mostly had similar perceptions about the explored topics in caries detection.
The key topic of knowledge about histopathology of caries lesions was considered for all participants as one of the most difficult to be learned. In addition, it was considered more dif ficult for graduate students than for senior lecturers. The com plexity in the integration of static images and dynamic physi ologic processes [11] can explain these findings regarding the cognitive learning process, even for higherlevel students [10]. The existing correlation between histological depth and clini cal appearance of caries lesions in the different stages is one of the main advantages of the ICDAS [5]. However, it is a chal lenge to visualize these characteristics in a pedagogical envi ronment and extrapolate them into clinical practice [12], mak ing learning and assimilation processes more complex. These aspects can also emphasize the need of finding manners to ex plore that in further learning tools.
Besides histopathology, detection of proximal caries lesions was another common difficulty regardless the level of academ ic background. Detection of proximal caries lesions and its management has been matter of concern in the last decade [1315] due to the inherent difficulty in the visual and tactile access to those surfaces. This complication has led to the de velopment and use of complementary methods assisting the detection of this type of lesions [1517]. Since this is a practi cal/clinical challenge, it is comprehensible that the perception of difficulty reported by participants in this study was similar. Moreover, practical skills directed to caries detection on these types of surfaces could be explored further during the learn ing process.
Differences were found when comparing perceived difficul ties reported by undergraduate students versus graduate stu dents/senior lecturers. The lack of clinical experience (limited contact with caries detection) and less accumulated knowledge could be pointed out as possible reasons why students consid ered some clinical situations as more difficult to be learned than lecturers. Some trivial aspects for lecturers, as differential diag nosis between caries lesions and extrinsic pigmentations or enamel defects/noncarious lesions, as well as correlation be tween clinical appearance of caries lesions and their radiograph Fig. 1. Analysis of the combined final score regarding the participants' perception of the degree of difficulty per topics. UG = Undergraduate students group; G/L = Graduated/Lecturers group. For topics from T1 to T11, please refer to Table 1.  T1  T2 T3  T4 T5 T6  T7 T8  T9 T10 T11 http://jeehp.org ic signs, could not be simple to their students understanding. Based on that, we can argue that academic background could have interfered in the perception of difficulties concerning learn ing these topics. These findings are especially important when developing pedagogical methodologies and should be consid ered when creating teaching resources related to caries detection. Usually, instructional material is prepared based on teach er's point of view. As our findings suggest, differential percep tion could be evidenced when teaching some specific points. Students' perceptions could help teachers in preparing learn ing material for their students, minimizing the inclusion of exclusively lecturers' impressions and considering possible difficulties the students reported in learning processes. We be lieve that educational tools addressed in order to also satisfy student's needs/expectations could contribute to knowledge acquiring, but especially in motivation to develop skills in cer tain area/field.
The results of this study are directed for the development of a learning object as a first phase of a pedagogical planning, as mentioned above. It is clear that the sample used in this screen ing may not reflect the global scenario about the perceived difficulty in this field. In this sense, more studies should be performed in order to explore this characteristic in different contexts.
In conclusion, histology of caries lesions and caries lesions detection on proximal surfaces are the topics perceived as most difficult in the process of caries detection by students and lec turers. Nevertheless, some topics including differential diag nosis between caries lesions and other manifestations, as pig mentations and enamel developmental defects are considered more difficult by undergraduate students than graduate stu dents and lecturers.